#qi-hardware IRC log for Tuesday, 2012-05-15

DocScrutinizer(t500) well it's just good enough for me00:08
DocScrutinizerbetter old solid stuff than the newest hottest crap00:09
wolfspraulman that's some dose of tech pessimism here00:11
wolfspraulluckily I think most new tech is actually *far* better than the old one, so I'm not worried :-)00:11
DocScrutinizeryou won't get a quality like T500 for 600 bucks new00:13
DocScrutinizerand actually it's terribly hard to find any decent anti-glare non-glossy display in a laptop nowadays00:14
wolfspraulcomputer prices are dropping and will continue to do so, driven by semiconductor economics as you know00:14
wolfspraulI would agree there is scary little innovation in notebooks, but we all know this for 10 years, no need complaining.00:15
wolfspraullet's do better00:15
wolfspraulhey btw, since we have the pessimists meeting here - will nokia go out of business?00:15
DocScrutinizerwho's complaining?00:15
DocScrutinizerI just stated I prefer used high quality 2 year old stuff to new stuff that's inferior quality for 4 times the price00:16
wpwrak(taking diy here) ok :)00:17
wolfspraulwpwrak: but watch out we have the pessimists coming after us :-)00:17
wolfspraulfor that - a sip of nice yunnan coffee...00:17
wolfspraulDocScrutinizer: I think I bought my last notebook, took it apart after buy and reassembled in new case, which was fun00:18
wolfspraulbut then I switched to a screen with back-mounted thin-itx board and battery and yes, it works just fine00:18
DocScrutinizerwpwrak: wolfgang confusing sane pragmatism with pessimism00:18
wolfspraulwpwrak: do you have any explanation why whitequark described his pcb-making in such dark words (months of fiddling, unstable, messy, eventually gave up), whereas what I saw at your place looked quite charming actually?00:19
wolfspraulwhat would help me if I would pick a realistic goal first - maybe atben clone?00:20
wolfspraulor you think that's too difficult00:21
wolfspraulDocScrutinizer: what's your take on the future of nokia?00:23
wpwrakwhitequark: i usually get my boards right one the first try :) they're small, though. i try keep things simple ;-) it only takes a lot of attempts if i try to rush things. haste makes waste, quite literally in this case ;-)00:23
wolfspraulI somehow think in the downfall there maybe a chance of a spinoff that could continue with a Linux phone00:23
wpwrak(get right) in the sense of the PCB being what i had in the design. then i discover the flaws in the design .. ;-)00:23
wolfspraulbut I'd say only 10% chance of that happening, more likely it will all be grinded down to nothing00:23
DocScrutinizer(spinoff) hard to see this perspective. I think they already fired all inhouse competence wrt linux/FOSS00:24
DocScrutinizerI expect Nokia becoming a M$-dependency00:26
wpwrakwhitequark: (scaling) in fact, it scales negatively. if you make a lot of boards, the error rate goes up :)00:26
wolfspraulof course, for scaling you send to a fab00:26
wolfsprauland for cost-down00:26
wolfspraulalthough I also think there are a lot of interesting pcbs with unique features a standardized fab cannot easily do, but that needs to be seen case by case00:28
DocScrutinizerlike what?00:28
wolfspraulI remember a long discussion with Andrey the Elphel founder about how he planned to make some special cuts into pcbs to be able to perfectly aline an image sensor with the lens00:28
wpwrak(nokia) why the future tense ? ;-)00:29
wolfsprauland how he was unable to find any pcb maker willing to work with him on that, for months, until he eventually gave up00:29
DocScrutinizerwpwrak: :-P00:29
wolfspraulwpwrak: please help! :-) which initial goal? atben clone?00:29
wolfspraulsomething else that is more interesting now?00:30
DocScrutinizeryeah, sounds good00:30
DocScrutinizernot too much too fine pitched stuff I assume00:30
wpwrakwolfspraul: (atben clone) it's a little demanding on the ME side. that uSD shape ... depends a bit on how confident you are with a dremel00:31
wolfspraulI don't even have a dremel. need to get a number of tools.00:31
DocScrutinizerduh, so I mistaken sth00:31
wolfspraulmy drilling machine broke yesterday because I abused it in cutting a line :-)00:31
wolfspraulwell, in good chinese quality it didn't totally break, but at high speeds it sputters (stops for a few seconds). middle speeds still work :-)00:32
wpwrakwolfspraul: i would pick something simpler. than atben/atusb. why not design your own circuit ? we have plenty of parts. i'd make something with an MCU, two LEDs, and a button. add USB if you want fancy.00:32
wolfspraulnah I can only motivate myself for something I actually need00:33
wolfspraulhow about labsw?00:33
wolfspraulyou dismissed anything with the xc6slx9 fpga as too difficult initially00:33
wpwrakwolfspraul: RF has one nasty property: if you want it to work well, you need make sure grounding is good. now, good grounding makes the soldering harder, too, because all those large ground areas near your chips act as excellent heat traps00:33
wolfspraulan fpga/atrf board would be nice00:34
wolfspraulhow about labsw?00:34
wolfspraulthat could come in handy00:34
wpwraklabsw is good but also a bit large. more like a 2nd stage project :)00:34
wpwrakfor the first try, the goal should be to make something where you can learn quickly. extra complexity only slows you down.00:35
wolfspraulatben clone00:35
wpwrakonce you're comfortable, you can move to more interesting things00:35
DocScrutinizermore interesting like doublesided ;-)00:36
wpwrakatben = hairy ME + RF. that's not an easy project. also, the board is densely populated and your vias must be quite precise00:36
DocScrutinizerwhich is like one magnitude more demanding than singlesided00:36
wpwrakoh, double-sided is good. particularly if the circuit is simple. so if you screw up, you can still fix the problems with patch wire. see if the rest works.00:37
wolfspraulthe bottom side of atben is just gnd?00:38
DocScrutinizerhonestly, start with a single or 1.5-sided PCB (one trace side plus GND backplane, so you can't mess up the via fitting)00:38
wpwraksingle-sided SMT is kinda boring. too easy ;-)00:38
wolfspraulI do see some traces there though...00:38
wpwrakwolfspraul: it's as much ground as possible :) but yes, i needed a few traces, too.00:38
wolfspraulwow there is almost nothing on the board, right?00:39
wolfspraulthe power only comes from ben?00:39
wolfspraulno converter, nothing? just from ben into the atrf chip?00:39
DocScrutinizerI think there's a mc as well?00:40
wolfspraulbut a local crystal, I remember you tried without but the ben's clock was usable/stable enough?00:40
wpwrakpower comes from the ben. and yes, very few components. very densely packed. lots of ground all over the place. a lot of vias to drill.00:40
wolfspraulwas not00:40
DocScrutinizeraah that's atusb I guess00:40
wpwrakDocScrutinizer: atben and atusb have a crystal. remember the phase jitter issue ?00:40
wpwrak(MCU) yes, that's atusb. atben is "dumb"00:41
DocScrutinizerI recall a shematics with two chips00:41
DocScrutinizerwhich I think was atusb00:41
wolfspraulatrf, 8 caps (0201), 1 resistor, 1 crystal, and then one other IC - what is that one?00:42
wolfspraulI should look at the schematics, open hardware here right? :-)00:42
DocScrutinizerwpwrak: btw what fixed the jitter issue finally?00:43
wpwrakwolfspraul: the components are 0402. i didn't venture into 0201-land yet. most people find 0402 challenging enough ;-)00:43
DocScrutinizerLOL, indeed00:43
whitequarkyeah, 0603 is already hard00:43
wolfspraulah ok, yes00:43
DocScrutinizerI'm just too old for that shit00:43
wpwrak0201 may actually not that bad. i mean, already 0402 is more by smell than by sight ...00:44
whitequarkLOL smell00:44
DocScrutinizerI heard 0201 is oxidizing away from mere plain air, too terrible mass/surface ratio ;-P00:45
wpwrakfor experts: 0201, with a trace crossing under the component, and have a via in one of the pads. if you can pull that off with DIY, you rock ;-)00:45
whitequarkDocScrutinizer: actually, I have some problems placing SMT components because my hands are shaking. not much, but enough to shift a 0603 horizontally by one position00:45
whitequarkand I'm 19 and I never drank alcohol, nor do I commonly drink coffee00:45
DocScrutinizerand I'm not focusing anymore on things closer than 40cm00:46
whitequarkso I guess that's implicit limitations of human beings00:46
DocScrutinizera nogo for unarmed eye00:46
DocScrutinizerSMT soldering00:46
wolfspraulwpwrak: I still think atben clone is a good first target00:46
wolfspraulI need something I can use myself00:46
wolfspraulthat or labsw00:46
whitequarkuh, I'm somewhat lucky here because I don't focus on things further than 40cm :)00:47
wolfspraulanything fpga you outlawed, for now. ok. accepted.00:47
wolfspraulwith atben it's just a few parts and I focus on the pcb and see how I can get it done and documented, should be neat.00:47
whitequarkwolfspraul: actually, just try making an atben. it's not like you are commiting to a longterm relationship with it or something like that00:47
wpwrakwhitequark: maybe you're not placing your arm/hand well. or maybe yuo have a small defect in your motoric system. try to rest hand and arm as much as possible. use small angled tweezers. if you notice your hand is shaking, do something else for a while. then 0603 should be no problem.00:47
whitequarkwolfspraul: if it will work, you're two orders of magnitude better at making pcbs than me00:48
whitequarkwolfspraul: if it won't, try something else00:48
wolfspraulthere is no way it will not work00:48
whitequarkwpwrak: I don't really have problems placing 0603's, it's perfectly manageable but requires some concentration, accuracy and preciseness00:48
whitequarkwpwrak: whereas for 0805's or even 1206's it's mostly a no-brainer00:49
wolfspraulwpwrak: what tools do I need? I start with a 0.8mm fr4, dual 1oz copper00:49
wpwrakwhitequark: (0603) ah okay. that it does :)00:49
wolfsprauldo you etch nowadays, or drill?00:49
wolfspraulI mean the copper00:49
wolfspraulfor etching, the process is still what I saw with laser printer and toner transfer?00:50
wpwrak1) i cnc-drill all the via holes00:50
wpwrak2) i cnc-mill any larger holes and the board outline00:50
whitequarkwpwrak: ahh, so that's how you managed to diy atbens. cnc explains everything.00:50
wpwrak3) i clean the board (steel wool and alcohol)00:50
wpwrak4) i toner transfer the layout. this is a bit tricky. if you can find that HP paper, that would be best. else, you need to search around. may taken 5-10 attempts before you find a paper that's good.00:51
wolfspraulHP will pay you to claim that they are still related to anything innovative :-)00:52
wpwrakwhitequark: yeah. atben is a bit tight for manual work. particularly the uSD card shape. of course, it can be done, but ...00:52
wolfspraulyou have this Roland some-15 machine, right?00:52
wpwrakwolfspraul: yeah, and even with such an old paper ;-)00:52
wpwrakmdx-15, yes00:52
DocScrutinizerthe engineer's 3D-printer00:53
wolfspraulany recommendations what is cheap and good nowadays, and easy to program/control?00:53
wpwraknot sure if it makes sense to get such a critter, though. i mean the mdx-15. it's a nice package, much like an office printer, but it also has its drawbacks00:54
whitequarkoh mdx-15. I WANT IT00:54
DocScrutinizeryou'll not get a decent CNC for <1000 bucks00:54
wpwrakdrawbacks being the weird language, the weak spindle, and the small work area00:54
whitequarkbut $3.5k isn't really manageable for me00:54
whitequarkDocScrutinizer: any advice on a good CNC in $1k-$1.5k range?00:55
wpwrakplus, inconvenient mounting (you can't clamp/screw things down. the only option is double-sided tape)00:55
DocScrutinizernot at all00:55
DocScrutinizerask roh - he seems more up to date with such stuff00:55
wpwraki don't know how whose low-cost chinese machines compare, though. maybe they have their own set of issues00:56
wolfspraulI will probably just buy something cheap here in beijing00:56
wolfspraulthat's the great thing about all the chinese "crap", it's wonderful for experimenting and learning, and then knowing what is really worth spending money for00:56
wpwrakhehe ;-)00:56
wolfspraulsince they will challenge every screw - "not needed"00:56
DocScrutinizerjust to find you got a reproducable precicion of >1mm ;-D00:56
wolfspraulthat's certainly up to me to find out :-)00:57
wolfspraulboth words "reproducible" and "precision" are not translatable into Chinese...00:57
wolfspraulno need00:57
wolfspraulthey make their billions without them00:57
whitequarkso true00:57
wolfspraulyes once you get the hang it's so empowering really00:58
DocScrutinizeryeah, for PCB on CNC they simply produce 50 boards and select the 2 that incidentally were good00:58
wolfspraulyou say pcb is hard00:58
wolfspraulha ha00:58
wpwrakyeah. the mdx-15 is pretty accurate in X/Y. the table moves quite a lot in the Z direction, though. maybe 0.5 mm if you push hard. now, normally there shouldn't be much vertical pressure, but you can still sometimes run into problems.00:58
wolfspraulI can do a brain surgery tomorrow!00:58
wolfspraulchinese docs can do it too, so can I00:58
wolfsprauljust give me some tools, and I will start00:58
wolfspraulfirst couple patients will probably die, but after some hundred it will get better00:58
wolfspraula friend here has one of those hyped makerbots00:59
wolfspraullet me see what that is00:59
wpwrakhappy ? :)00:59
wolfspraulexcept for unpacking and showing people how cool they are they will have no use for it00:59
wpwrakmakerbots and the like are additive. so you need to apply the material you want in the end. alas, they don't print FR4, copper, and such01:00
wolfspraulah ok, that probably won't help then01:00
wpwrakso for pcbs, you want a mill01:00
wolfspraulI just want a simple drill/mill like you have01:00
wolfspraulideally fully controllable from standard linux tools etc01:00
wpwrakyou'll need a more or less dedicated PC for the parallel port01:01
wolfsprauldremel? you mean a hand dremel? you need that for what?01:01
wpwrakall the cheap ones leave the control work to the PC. and the PC is bit-banging the motor signals. as low-level as it gets :)01:01
wpwrak(dremel) that would be the tool if you don't have CNC. or for the occasional retouching.01:02
DocScrutinizertoldya, CNC mill == engineer's makerbot / 3-D printer01:02
wolfspraulI fail to see the application for the additive 3d printers I've seen so far01:03
wolfspraulthey are insanely slow, large tolerances, just a joke really01:03
wolfspraulmaybe I could make doorstops or so01:03
wolfspraulor candle holders01:03
wolfspraulthat would fit aesthetically01:03
wpwrak3d printers are less messy than CNC mills. and some can also print overhangs. that's something the basic CNC mills can't make01:04
DocScrutinizerproper 3D printers start at nn kBucks01:04
DocScrutinizerand weigh tons01:04
wolfspraulyes sure, but we try to be very practical here01:04
DocScrutinizerwpwrak: yup01:04
wolfspraulwpwrak: it seems you are happy with your mdx-15 and will continue to use it... so that's a good guidance01:05
wolfsprauland you built a neat noise-cancelation box around it :-)01:05
wolfspraulwhat exactly is that HP paper?01:05
wpwrakperhaps an in-house 3d printer can be good for very rough prototypes. so that you can hold the thing in your hands, turn it around, feel it.01:05
DocScrutinizergoldelico has printed GTA02 cases now, in translucent white 01:05
wpwrakthe mdx-15 is all i have :) if i had a lot of money, i'd probably try to find a 4 axis machine. but we're quickly talking USD 10k+01:06
wpwraki may need a bigger apartment as well ;-)01:06
wolfspraulstill need more data01:07
wolfspraulwhat HP paper you recommend?01:07
wolfspraulhow did that transfer work again?01:07
wpwrakC6039A: HP Premium Photo Paper, glossy01:07
wolfspraulfirst print on the laser, then use your stepper-motor modified whatever-it-was to transfer/burn the toner onto the copper?01:08
wpwrakor the same kind of paper but in a different size. the product code changes with size and number of sheets in the package.01:08
wolfspraulhow about just using an iron to transfer it?01:08
wpwrakthe laminator, yes01:08
wolfspraulyou need heat & pressure?01:08
DocScrutinizeryup, just like inside laserprinter01:09
wpwrakyou can use a clothes iron instead. need a bit of figuring out the technique, though. ironically, i found that women seem to have a lot less difficulties with it than men ;-) (a few friends have built circuits using this process)01:10
wpwrakheat and pressure, yes01:10
wolfspraulok, sounds like iron first01:11
wolfspraulwhat chemicals do you need for the etching?01:11
DocScrutinizerumm, now it gets funny01:11
wpwrakyeah. also modifying the laminator can be a bit messy. i made a very simple circuit that works but poorly01:11
wolfspraulanything to watch out for in the laser printer?01:11
wolfspraulsure I will try to skip that01:11
wpwraki use muriatic acid and peroxide01:11
DocScrutinizeryeah, you might mess it up 01:12
wolfspraulI will go out and buy cheap chinese tools, whatever I can find, and then reverse from there. rather than following a perfect spec.01:12
wolfspraulit was a 2-step process, right?01:12
wolfspraulyou have the etching bath, put it in there for xx seconds, then out and into a second cleaning bath?01:12
DocScrutinizeralso I think tones can differ vastly01:13
wolfspraulmaybe but no point to over-plan and assume the worst01:13
DocScrutinizermake sure you're printing as 'fat' as possible01:13
wpwrak(laser printer) the straighter the paper path, the better. some have a backdoor you can open and then the paper doesn't get turned around01:13
wolfspraullike I said, when the experiments are cheap and fast, they are fun (and valuable) no matter what the outcome01:13
wolfspraulstraight - excellent, makes sense01:13
wpwrakbut in general, it seems that any printer will do. you may have to vary the transfer paper, though01:14
wolfspraulcan  you prepare the copper in some way for better transfer?01:14
wolfspraulI would think there are many ways to transfer it over01:14
DocScrutinizerI think wpwrak already mentioned copper conditioning01:14
DocScrutinizercleaning and polishing01:15
wpwrakyou must clean the copper before the transfer. so you scrub it with the steel wool until it's shiny. then you wash/rub off the steel wool with alcohol.01:15
wolfspraulsandpaper also ok?01:15
DocScrutinizerprobably not01:15
wpwrakthen quickly, before it oxidizes again, do the transfer. if it fails, remove the toner with paint thinner or acetone, then repeat the cleaning process01:16
wpwrakmaybe if you can find very very fine sandpaper. but steel wool should be easier. any supermarket has that ;-)01:16
wolfspraulsandpaper vs steel wool?01:16
wolfspraulvery fine, hmm01:17
wolfspraulcorning 500 is no problem here01:17
wolfspraulthey have sandpaper everywhere, from about 100 to 500 I think, have never tried to look for extremes though01:17
DocScrutinizermore like 140001:17
wolfsprauland the steel wool is less intrusive? I would have never thought01:17
DocScrutinizerwell, steel wool is less hard than sand paper01:18
wolfspraulI would think that the steel wool creates deep scratches, whereas say a corning 500 sandpaper feels quite smooth01:18
wolfspraulok, thanks01:18
wolfspraulI will try01:18
DocScrutinizerand copper is harder than most other materials you usually apply steel wool to01:18
wpwrakyou want the fine steel wool. with almost hair-thin steel. not the coarse with "noodles"01:18
wolfsprauldepends on applied pressure too, of course01:18
wolfspraulok [hair thin]01:18
wolfspraulthe etching...01:19
wolfspraulneed more data01:19
wolfspraul2 step?01:19
wpwrakyou can get scratches, yes. you can also experiment a bit with what works best.01:19
wolfspraulyou buy the chemicals or make yourself? which chemicals do you buy?01:19
wolfspraulI recently discovered a "home improvement" market nearby01:19
wolfspraulactually VERY NEARBY01:19
wolfspraula bit scary01:20
DocScrutinizersomething you go to prison when buying in USA ;-D01:20
wolfspraulthey have little shops who are piling up chemicals in their little barracks until under the roof01:20
wolfspraulkids playing there, on the barrels etc.01:20
wolfsprauland I am *sure* those people know *nothing* about chemistry01:20
wolfspraulnothing, zero01:20
wpwraketching: mix the etchant, toss the pcb inside, move it around until it's finished, remove, rinse, check visually. if you find insufficiently etched bits, toss it back in. otherwise, wash carefully, then proceed with tinning.01:21
DocScrutinizerthat's China how we love and know it01:21
wolfspraulI will keep my shopping there very focused01:21
wolfspraulin, want this, that and that, pay, out01:21
wpwrakhow nearby ? downstairs neighbour ? ;-)01:21
wolfspraulwith all my wikipedia research about chemicals, I know 100 times more about those things than them who are storing 100 times more right where they sleep with their whole family...01:21
wolfspraulscratch that, 10,000 times more than me01:22
wpwrakalways keep the muriatic acid next to the caustic soda and nothing can go wrong ;-)01:22
DocScrutinizerif you can get ammoniumperclorate, I think it's a good etching01:22
wpwrakmaybe also keep a few canisters of 50% peroxide around, just in case :)01:22
wolfspraulok one by one01:22
wolfspraulso it's only 1 bath, the rinse with normal water?01:22
DocScrutinizerwtf is muriatic acid?01:22
wpwrakyes. it's only 1 ml or so that you need to get rid of01:23
wolfspraultap water here probably has a few hundred unknown chemicals in it anyway01:23
wpwrakDocScrutinizer: HCl01:23
wolfspraulwait, I need this in the right order01:23
wolfspraul1. what do you buy01:23
wolfspraul2. how to you mix/prepare01:23
wpwrakwolfspraul: there are several chemical processes what people use for etching pcbs01:23
wolfspraul3. the bath you described and remember from my visit01:23
wolfspraul4. rinse with tap water01:23
wolfspraul5. how to dispose of the rest01:23
wolfspraulsure I can imagine, but let's just focus on yours01:23
wolfsprauland watch out joking with me, I may not get it01:24
wpwrakthere if Fe(III)Cl (or some such), there is ammonium chloride, there is natrium chloride, and there's HCl+Peroxide. plus a few even more exotic ones.01:24
wolfspraulthen I end up with some bomb, since the people I buy from certainly know even less than me01:24
wolfspraulyes but let's focus on your process01:24
wpwrakah, let's talk about the fertilizer then .. ;-)01:24
wolfspraulcan you walk me through?01:25
wolfsprauljust what you do01:25
wolfspraulwhat do you buy01:25
wolfspraulhow do you prepare/mix01:25
wpwrakFeCl = traditional, needs heating, considered pretty "safe" to handle.01:26
wolfspraulthe application I think I'm clear (as described above), then disposal01:26
DocScrutinizerslow and messy01:26
DocScrutinizermuch dirt01:26
wpwrakammonium chloride and natrium chloride (actually, it's not NaCl ... must be something slightly different) = cleaner than FeCl, still considered "safe", work at room temperature01:27
DocScrutinizernatrium chlorite maybe?01:28
wpwrakFeCl drawbacks: it's a ugly brew, rost-brown to nearly black. stains everything it touches. loses transparency after a bit of use. will not evaporate.01:28
wolfspraulwhat is your known best and latest practice?01:28
DocScrutinizerriuns your cloths and skin01:29
wolfspraulI will focus on that01:29
wpwrakammonium chloride and such drawbacks = harder to obtain, slow01:29
whitequarkthere's also ammonium persulphate01:29
whitequarkit's pretty awesome: easy to obtain, clean01:29
DocScrutinizernot perchlorate but persulphate01:30
whitequarkthrough it ruins clothes even faster than FeCl(III)01:30
DocScrutinizerI guess I mixed it up somehow01:30
wpwraknow, HCl + H2O2 = clear solution, stays transparent, works at room temperature, you can choose how fast you want it to be, you can let it evaporate and then only have to dispose the solids01:30
wolfspraulthat's your current process?01:30
wpwrakHCl + H2O2: ingredients extremely cheap and easy to find (hardware store and pharmacy)01:31
wpwrakyes, HCl+H2O2 is my current process01:31
wolfspraulyou buy hcl and h202 separately?01:31
DocScrutinizerkeep away any organic solvent from this though!!!!01:31
DocScrutinizeresp acetone01:31
wolfspraulhcl = hydrogen chloride01:31
wpwrakdrawbacks: need to control the chemistry a bit. releases Cl gas.01:31
wpwrakhcl = muriatic acid ("salzsaeure")01:32
wolfspraulah ok, hydrochloric acid, i.e. solution of hydrogen chloride in water01:32
DocScrutinizerand keep clear of the gas!01:32
wpwrakh2o2 = peroxide. at high concentrations, peroxide is used as rocket fuel.01:32
wpwrakat low concentrations, as wound desinfectant01:33
wolfspraulthis one? http://en.wikipedia.org/wiki/Hydrochloric_acid01:33
wpwrakfortunately, you'll only need the 5% variant01:33
DocScrutinizereasily found at barbers01:33
wpwrakyou may want to keep a bottle of ~30% around to recycle your acid. but that's already advanced use.01:33
wolfspraulwait wait01:33
wolfspraulI'm still with the hcl acid01:34
wolfspraulwhat concentration of that?01:34
wpwrakany pharmacy has 5% peroxide. liters of it. probably hundreds ;-)01:34
wpwrakthe "standard" concentration. i think it's 35%. could be 30%, though.01:34
wpwrakthe one they have at hardware stores. it's used for plumbing work. not sure what exactly the plumbers do with it, though.01:35
DocScrutinizercleaning copper ;-D01:35
wolfspraulperoxide is a liquid too?01:36
wolfsprauland I need a 5% concentration01:36
wolfspraula bottle of 30% concentration for "recycling your acid"?01:36
wolfsprauldon't understand01:36
DocScrutinizerbetter forget that01:36
wolfspraulthen you mix the 35% hcl and 5% h2o2 ?01:36
wolfspraulin which way?01:37
DocScrutinizer30% H2O2 is actually dangerous01:37
wpwraki think it was 1/3 hcl, 2/3 h2o201:37
wolfspraulmy #1 concern with all this would be that what I think I buy is not what I actually buy01:37
wpwrakbut you may want to experiment a bit. you can also add a bit of either while etching.01:37
wolfspraulthe sellers here operate with 0 knowledge, if anyone can imagine this01:37
DocScrutinizerwolfspraul: indeed01:37
wolfspraulI think you cannot, unless you lived in china for a while and get the feeling on how this works01:37
wolfspraulso I actually would only trust the concentration if I measured it myself, in some way01:38
wolfsprauland if the measurement equipment was imported :-)01:38
wolfspraulbut anyway01:38
wolfspraullet's keep on our over-knowledge path...01:38
DocScrutinizeranyway you'll easily check for general properties of your chemical. HCl is easily detecable by smell, H2O2 will act like sodawater on any wodden surface01:38
wpwrakthe 30% H2O2 would be for increasing the H2O2 concentration if the solution gets stale. or if you've let it sit for a while. and yes, that's something you don't touch without gloves :)01:38
wolfspraul1/3 hcl, 2/3 h2o2 ?01:39
wolfspraulhow much do you make typically?01:39
wpwrakwolfspraul: i doubt the pharmacy will have peroxide much stronger than 5%. maybe 10%, which would be used for hair bleaching. anything stronger and the customer feedback will be quick and unfriendly :)01:40
wolfspraulthose are both liquids - any danger of them reacting with air, something else, evaporating?01:40
wolfspraulI go to the 'home improvement' market around the corner01:40
DocScrutinizera basin large enough to hold your PCB, and 5..10mm high01:40
wolfspraulI wouldn't be surprised if they are selling used equipment from all sorts of nuclear facilities around beijing, without knowing what it is01:40
wpwrakHCl can evaporate out of the bottle (unless the bottle is good enough). so better keep the bottle outdoors01:40
wolfspraulthe problem is not what I can get, but whether I know for sure what I get01:40
wolfspraulbut that's my problem01:40
DocScrutinizerwolfspraul: yes, toldya DO NOT GET THEM in contact with acetone01:40
wolfspraulI think this is actually a small miracle. the semiconductor industry uses large amounts of really dangerous chemicals01:41
wolfspraullike arsine01:41
wolfspraulgallons and gallons of it01:41
wpwrakthe 5% peroxide should be as harmless as it gets. i mean, i wouldn't drink it, but i don't think it makes a mess with anything else.01:41
wolfspraulbut I think until today, there never has been 1 fatality01:41
wolfspraulbut then, china is still behind in that industry, and if there were a fatality it would surely be covered up01:42
wolfspraul(in china)01:42
wpwrakthey probably just seal off the valley and wait until the screaming stops. no bad news ;-)01:42
wolfsprauldo you know how many and what large amounts of *really* dangerous chemicals are used in semiconductor making? I had no idea...01:43
DocScrutinizerwolfspraul: pretty please read http://de.wikipedia.org/wiki/Acetonperoxid01:43
wpwrakwell, you need some pretty aggressive etchants ..01:43
wolfspraulalright, so...01:43
wolfspraulthat 1/3 hcl + 2/3 h2o2 is our etching solution01:43
wpwrakoh, and if you have the higher grade peroxide, you can etch your board in something like 5-10 seconds ;-)01:43
wolfspraulboth liquids, store hcl outside01:44
wolfspraulhow much do you make typically?01:44
wpwrakof course, at some point in time, the solution starts to boil, etc. ;-)01:44
wpwrakas little as i need01:44
wolfspraula few hundred ml?01:44
DocScrutinizerno way01:44
wolfsprauljust a shallow bath to put the pcb into?01:44
wpwraka few ml :)01:44
wpwrakyes, shallow bath01:44
wolfspraulyeah ok, but then 10-50 ml are probably needed, no?01:45
wolfspraulI mean how do you want to cover even an atben in "a few ml"?01:45
wpwrakdepends on the size of the board, its thickness, the curvature of the bottom of the container01:45
wolfspraulah the container01:45
wolfspraulwhich material?01:45
wolfspraulany household plastic? metal?01:45
DocScrutinizerdepends on size of PCB and how good it matches the comtainer01:45
wpwraki have small beakers. just a few cm in diameter01:45
wolfspraulglass, hmm01:46
wpwraktry metal and watch the acid go to work elsewhere ;-)01:46
DocScrutinizerI think any plastic will do01:46
wpwrakno idea about plastic. i'm a bit risk-adverse when it comes to that ;-)01:46
wpwrakceramics will do too01:46
wolfspraulrice bowl?01:46
wpwrakif it has a flat bottom ... :)01:47
DocScrutinizermore like a soup dish01:47
DocScrutinizerI'd try a nice plastic box01:47
wpwrakmore like a serving bowl. a non-round one01:47
DocScrutinizeryou'll notice if it doesn't stand your test01:47
wpwrakand you want reasonably high sides01:47
wolfspraulsure I try with some drops01:47
wolfspraulwhat are the immediate dangers from mixing and using this solution?01:48
wolfspraulno contact with skin probably, ok01:48
DocScrutinizersee above01:48
wpwrakplus, you want a secondary containment. for spills and such. and in case anything goes wrong.01:48
DocScrutinizerapart from skin irritations and injury on eyes01:48
DocScrutinizerwolfspraul: pretty please read http://de.wikipedia.org/wiki/Acetonperoxid01:48
wpwrakevaporation, yes. chloride gas01:48
wolfspraulyes sure01:48
wolfspraulDocScrutinizer: I do read this stuff01:48
wolfspraulbecause I'm curious01:48
wpwrakunpleasant to inhale, so you're not likely to do that long enough for it to be really dangerous01:49
wolfspraulbut I described the real issue to you :-)01:49
wolfspraulnot only the cigarette-smoke like air I breath every day01:49
wolfsprauland the tap water I use for cooking that contains an unknown number of unknowingly dangerous things01:49
wolfsprauland the fish with antibiotics01:49
wolfsprauland the pigs that are slaughtered when having high fever and also pumped full with medication01:49
wpwrakwhat's more of a concern is Cl gas escaping after you're done. so again, store this outdoors and away from metals.01:50
wolfsprauland the sellers of chemicals who have no clue what they are doing01:50
wolfsprauland filling liquids from one bottle into another at will01:50
DocScrutinizerjust don't dare to mix your etching mix with anything else, esp not the thinner you're using to remove the toner01:50
wolfspraulwriting on the label whatever they want, or maybe not01:50
wolfsprauland reselling01:50
wolfsprauland and and01:50
wolfspraulI can read in wikipedia all I want01:50
wolfspraulstill need to be careful not to touch open wires on the street, or else...01:50
wpwrakif you can seal the container, you can reuse the acid. but you may need higher-grade peroxide to reactivate it after storage.01:50
wolfspraulcl gas, hmm01:51
wolfspraulyou mean out of the hcl acid bottle?01:51
wpwrakif you can't seal the container, i'd just let it evaporate. you'll get some bluish-green crystals that fit nicely in the trash. even though they probably shouldn't go there :)01:51
wpwrakboth from the HCl bottle and from the etching solution01:51
wpwrakboth release Cl gas01:52
wolfspraulthat's my least concern, I help the trash on the landfill balance out better :-)01:52
DocScrutinizeronce you want to get rid, I'd mix the shit with chalk or sth, maybe even flour, then just dispose it01:52
wolfspraulok but the eching solution is only around for some X minutes, no?01:52
wolfspraulwhereas the bottle of hcl acid may stand there for days, weeks, months01:52
wpwrakDocScrutinizer: if you mix it, you may make it more stable and then you have a liquid to get rid of. much messier.01:52
wolfspraulthey have bottles with plasticky covers on top, that snap around the glass01:53
wolfsprauldoesn't look very tight, but not bad either01:53
wpwrakdepends. you can use the etching solution just once or you can use it for years01:53
DocScrutinizerwolfspraul: nope, you usually keep the etching liquid, it's ok for several boards01:53
wolfspraulah I see01:53
wolfspraulbut then you would want to fill it back into a bottle?01:53
wolfspraulor keep in the etching container?01:53
wpwrakthe actual etchant is generated in the process. HCl+H2O2+the copper of the PCB react first to form cupric acid. and then it's the cupric acid that takes over the etching.01:54
DocScrutinizerif it'sa a nice tupperware box01:54
wpwraksome people cultivate their cupric acid for ages ;-)01:54
wpwraki tend to just let all the stuff evaporate, then toss the crystals. it's cents anyway ;-)01:54
wolfspraulsounds cleaner to me too01:55
wpwrakevaporation will take a while, though. depends on ambient temperature and humidity.01:55
wolfspraula while = ?01:55
DocScrutinizerwell, otoh it's probably not worth the hassle to keep such small amount of etching fluid, esp when it's based on H2O2 which is instable01:55
wolfspraulyou take the board out with some tweezer, then under tap water?01:55
DocScrutinizerwear goggles01:55
wolfspraulwith the tap water you probably wash a small amount of the etching solution off as well01:56
wolfspraulno problem with that?01:56
wolfspraulit wont' destroy the pipes?01:56
wpwrakDocScrutinizer: yes, the H2O2 escapes/decays. that's why you need higher grade peroxide to restore the acid if you store it.01:56
wolfspraulor say - damage01:56
DocScrutinizerunless you recycle your greywater in a pond in the garden...01:56
DocScrutinizerwolfspraul: nope01:56
DocScrutinizerway too dilluted01:57
wpwrakwear gloves. latex or plastic01:57
wolfspraulbut you cannot just dispose of the entire etching solution in this way?01:57
DocScrutinizeryou can01:57
DocScrutinizerif you don't mind01:57
wolfspraulI would mind damaging the pipes01:57
DocScrutinizerdillute 10:101:57
DocScrutinizerno problem, really01:57
wolfspraulbut then I live in a household where pretty much anything can and will break at any time01:57
wpwrakyou can use tweezers or just a wooden stick (the one you use for grilling small chunks of meat ... don't remember the english word. "spiess" in german) to handle the pcb01:57
wolfspraulso it's hard to see causes :-)01:58
wolfspraulwooden stick = chopsticks?01:58
DocScrutinizerdillute, flush with 10L water01:58
wpwraktoo big :)01:58
DocScrutinizerbut that's absolutely not PC01:58
wolfspraulah the problem with tweezers would be if they are metallic?01:58
wpwraki wouldn't want to take the risk of releasing all that acid. you never know if it may not end up somewhere in a higher concentration that you expect.01:58
wolfspraulbut maybe for quickly taking a pcb out it doesn't matter, just wears down the tweezer over time, so what01:59
wpwrakbut the drop or two that you rinse off the board surely won't do anything.01:59
wpwrakno metals ;-)01:59
wolfspraulbut it won't affect it so quickly, no?01:59
wpwrakalso don't wear metal gloves ;-)01:59
DocScrutinizeryou see people clean their toilets with HCl all over the globe02:00
wpwrakwell, depends ... sure, it'll take a while for it to eat your tweezers (unless you go the the etch-the-board-in-seconds approach)02:00
wolfspraulseems I can dilute 50ml of that solution in 10L water, and down the drain02:00
DocScrutinizereven with concentrated HCl you usually can't etch iron02:01
DocScrutinizeror steel02:01
wolfspraulalright I think it sounds pretty clear now02:01
wolfspraullemme think02:01
wpwrakwhat you have isn't HCl anymore. it's cupric acid.02:01
wpwrakand i don't know what that does to iron. or whatever else is there in your pipes.02:01
wolfspraulI wish I have the actual 35% hcl at the beginning02:01
wolfspraulthe less uncertainty the better, so I will probably dispose of that etching solution02:02
wolfspraulor just into the garden02:02
wpwrakso, the shopping list: 35% HCl from hardware store, 5% peroxide from pharmacy (it's used as a desinfectant, just like alcohol)02:02
wolfspraulwhy does it matter where the 5% peroxide comes from?02:03
wpwraknext, latex/plastic gloves. also get some goggles or glasses, in case something spills02:03
DocScrutinizerif you can get 10%, I'd prefer that02:03
wolfspraulthe normal gloves they have for household work shoudl be fine?02:03
wpwrak5-10% should both be okay.02:03
DocScrutinizermind you, 65..70% of the HCl are water as well02:03
wpwrak(gloves) if they're thin enough that you can actually manipulate things02:03
wolfsprauland I keep the hcl and h2o2 away from acetone02:04
wolfspraulah they also have these factory gloves, they are very fine02:04
wpwrakand any other solvents, paint thinner and such02:04
wpwrakDocScrutinizer: have you had some of that stuff go off by accident ? ;-)02:04
wolfspraulI have a bottle of acetone here, which I would think is also slowly evaporating (don't trust the seal on the bottle entirely)02:04
DocScrutinizernot THAT stuff02:04
wolfspraulif it is acetone, well, it smells like :-)02:05
wpwrakfine gloves are good. as long as they're watertight.02:05
wolfspraulany danger of smelling the hcl or h2o2?02:05
DocScrutinizerammonium-joidine though...02:05
wolfspraultrust me, even by know I already know 100 times more about hcl and h2o2 than any of the people I will talk to to buy from :-)02:05
wolfspraulby now02:06
wolfspraulwhat comes after etching02:07
wolfspraulrinse with water02:07
DocScrutinizerwolfspraul: H2O2 is "harmless" regarding gas, HCl you'll manage to stay away02:07
wolfspraultoner is still on, I guess02:07
wolfspraulDocScrutinizer: but smelling on a hcl bottle is a no-no?02:07
DocScrutinizeryou don't do that, believe me02:07
wpwrakyou'll understand very quickly why it's a bad idea ;-)02:08
wolfspraulhow does the story continue?02:09
wolfspraulrinse with water02:09
wpwrakif you want to play chemical emergency, get some caustic soda, dissolve it in water (exothermic, so beware), open the window, then mix that solution with a bit of hcl. run ;-)02:09
wolfspraulI try to stay focused and have some knowledge safety around me02:09
wolfspraulmy main difficult is starting with known chemicals02:10
wpwraki experimented with the when trying to neutralize my FeCl. what a mess ...02:10
wolfspraulbecause they can easily mix and match whatever in their mess02:10
wolfspraulfor example when I say I want "35% hcl", I am sure they will start some action with multiple bottles02:10
wolfspraul"let's take this bottle"02:10
wolfspraul"fill it over into this one, it's the right size for you"02:11
wpwrak35% HCl is pretty much the standard concentration.02:11
wolfspraul"then fill the liquid from this one into that one"02:11
DocScrutinizeraah yes, when contact to skin: rinse with plenty of water, best with some soap (no joke!)02:11
wolfspraul"and now hastily write over the label in some unreadable mumble jumble"02:11
wolfspraulplug on top, cash, done and out02:11
wolfspraulI'm sure I could return unused chemicals to them, and they would just fill it right back into the bigger bottles02:12
wolfsprauland so on02:12
wolfspraul(I mean I sell the unused part back to them :-))02:12
wolfspraullearning by doing02:12
DocScrutinizerdon't order 35% HCl, just ask what they got!02:12
DocScrutinizerask for HCl, they will offer 30..35%02:13
wolfspraulhopefully, anyway that is my problem02:13
wolfspraulnot the amount of knowledge I have02:13
DocScrutinizerbtw all this is extremely error tolerant02:14
wolfspraulI could get something different, a little different, or a lot different02:14
wolfspraulyes I figured, of course02:14
wolfspraulit's a simple process, sounds like02:14
DocScrutinizerif you get 10% HCl, you just will need 5 times longer to etch02:14
DocScrutinizerand I guess there's rarely ever HCl with significantly higher than 40% concentation02:15
wolfspraulI'm not that stupid, I would be able to tell if some procedure depends on very fine tolerances, exact relations, temperature, pressure, etc. etc. and I probably wouldn't want to do it then.02:15
DocScrutinizerif the bottle starts smoking when you open it, be careful! ;-D02:15
wolfspraulwpwrak: what comes after etching?02:15
wolfspraulthe toner is still on after the water rinse?02:16
wolfspraulyou eatch both sides together, I would think02:16
DocScrutinizeralso yep02:16
wolfspraulyou need to turn the pcb around in the etching solution, or not needed?02:16
DocScrutinizernot exactly needed, though you want to watch both sides02:16
DocScrutinizerso you'll turn it anyway02:17
wolfspraulwhy did wpwrak say a few times to get the h2o2 at the pharmacy?02:17
wpwrakand you normally have to turn it from time to time02:18
DocScrutinizeryou however should find a small glass object to put on the floor of the container, so the PCB downside is in liquid, not on floor02:18
wpwrakbecause the acid will flow differently over the board. you have to move the board around in the acid.02:18
wolfspraulyou mean a stand?02:18
DocScrutinizersth like that, yeah02:18
wolfspraulyeah sure, I remember from seeing and I think that should be easy after some attempts02:18
wolfsprauland it sounds like you can use the same etching solution for a few hours?02:19
wpwrak(pharmacy) because they're everywhere and because they won't accidently sell you 80% peroxide ;-)02:19
wolfspraulor will it all evaporate by then?02:19
wpwraka few hours shuold be good. next day maybe not02:19
DocScrutinizerH2O2 might gone inactive though02:19
DocScrutinizeryou add some more02:20
wpwrakyou'll notice when the solution gets weak02:20
wolfspraulcan I just fill in more h2o2 then?02:20
wpwrakDocScrutinizer: drawback of a stand: it increases the amount of acid you need02:20
DocScrutinizersure, it should be 1..3mm max02:20
wpwrakto some degree, yes. if you add too much 5% h2o2, the water content of your acid gets too high and it doesn't work very well anymore02:21
DocScrutinizera smal glas splinter02:21
wpwraki'd just move the pcb over the floor of the container. the flow is usually stronger on the bottom than on the top anyway02:22
wolfspraulbut if you have a higher percentage h2o2 it might work02:22
DocScrutinizerthat#s why I suggested to use 10% if available02:22
wolfspraulafter rinsing - what's next02:22
wpwrakyes. but careful: if you add, say, 30% peroxide to the mix, and you drop it right on top of the pcb, you may get some very fast etching on that spot before the h2o2 gets properly mixed02:23
DocScrutinizeryou use.... Acetone ;-P to remove the toner02:23
wpwrakyeha, 10% is still safe and controlable02:23
wpwrakacetone or paint thinner/remover02:23
wolfspraulyou mean the etching will undercut the toner?02:24
DocScrutinizerthat's where my pun about going to jail for buying chemicalc kicks in02:24
DocScrutinizeryes, this can happen02:24
wolfspraulok rinse with lots of water, then directly proceed to acetone?02:25
DocScrutinizermain reason why you want equal etching over the whole area02:25
wolfsprauluse the steel wool again?02:25
wolfspraulhow does it continue?02:25
wpwrakacetone is used for drug production. so it may be difficult to obtain at some places. e.g., in argentina, i have to bring an id document to buy it. some shops may even require a written declaration of the use.02:25
wolfspraulshould I praise the *freedom* of china?02:26
wolfspraulI could buy a hectolitre of acetone right in my neighborhood02:26
wolfspraulthat won't get me in jail02:26
wolfspraulbut 1 tweet about democracy would02:26
wolfspraulamazing how diverse our world is, no? :-)02:26
wolfsprauloh, and if I would make and sell drugs - death penalty02:27
wolfspraulof course02:27
wolfspraul1 week from 'catching' to execution02:27
DocScrutinizermixing accetone with etching fluid will get you either in prison as well, or on cemetary02:27
wolfspraulwith a mobile bus, organ harvesting included, of course02:27
wolfspraulyes I understand02:27
wolfspraulbut I just rinse with water, that sounds like enough to keep the 2 chemicals apart02:27
wolfspraulthen acetone, right?02:27
wolfspraulthen what?02:27
wolfspraulmore steel wool?02:27
wpwrakhere it would be a slap on the wrist. unless you drug business was not successful enough to produce sufficient bribe money. or, of course, if it was too successful, the competition would remove you.02:28
wpwrakno steel wool02:28
wpwraktoner removal is all solvent + paper towel02:28
DocScrutinizeryes, enough to keep them apart02:28
wolfspraulpaper towel, ok02:28
wpwrakyou need lots of paper towels. also for the alcohol you used first to remove the steel wool02:29
wolfsprauloh that was before etching?02:29
wolfspraulyou said steel wool, then clean with alcohol?02:29
wolfspraulclean with alcohol better than with acetone?02:29
DocScrutinizererr, for removing steel wool, I dunno if alcohol is maybe better02:30
wpwrakalcohol is for the steel wool02:31
wpwrakacetone is for the toner02:31
wolfsprauljust a high-percentage one I would think - 70%? 95% ?02:31
DocScrutinizerafter all alcohol usually has some water, acetone hasn't02:31
wpwrak95+% alcohol. you can get it basically pure. ideally in spray cans.02:31
wolfspraulalcohol before etching, then acetone after etching, then again alcohol with paper towels after toner is off02:32
DocScrutinizersounds good02:32
wolfsprauldo you seal the open copper traces etc in any way?02:32
wpwrakyeha, i usually swipe off the acetone with alcohol. not sure if it's needed.02:32
DocScrutinizeryou'll see when copper is clean02:32
wolfspraulto leave only pads open?02:33
wolfspraulhave you done any silkscreening?02:33
wpwrakwell, or tather the paint thinner. which is assuredly a vile brew. and quite oily.02:33
DocScrutinizeryou could varnish whole board with so called loetlack, dunno the english name. basically colophonium in alcohol02:33
wpwrak(i use paint thinner instead of acetone. no bureaucracy :)02:34
DocScrutinizeryou don't probably want to do this for SMT02:34
wolfspraulwait, what is that for?02:34
wolfspraulnow we have a clean board. toner removed with acetone/paint thinner, board and copper cleaned with alcohol and paper towels.02:34
wpwraki seal the copper traces by "painting" solder on it. see the backlog from a few days ago ;-)02:34
wolfspraulnow what?02:34
wolfspraulto avoid copper oxidization?02:35
wolfspraulthat's still conductive though02:35
wpwrakand it also improves solderability02:35
wolfspraulsearching backlog, one sec02:35
wpwraksolder is conductive, yes ;-)02:35
DocScrutinizeryou could also put the whole PCB in a galvanic bath not, and coat traces with silver or even gold02:35
DocScrutinizers/ not / now /02:36
wolfspraulah yes02:36
wolfspraul"I tin the board first" "tin = apply flux, then paint tiny amounts of solder"02:36
wpwrakthere are a number of ways to do this tinning. just "painting" the solder is easy and you only use things you already have02:37
wolfspraulwater-soluble flux you said02:37
wolfspraulwhat is that exactly?02:37
DocScrutinizeryeah, you should get good flux02:37
wolfspraulthe 'painting' you said you just do with your soldering iron?02:38
DocScrutinizeractivated resin type02:38
wpwrakit's a chemical that, when heated, etches oxides away, and that also helps to reduce the surface tension of the solder02:38
wpwrakRA is messy. water soluble is friendlier. i hate no clean. these are the three main categories.02:39
DocScrutinizerI got a bottle here: ALMIT, flux 20ml T419, www.dubreh.nl02:39
DocScrutinizerhah, currently down for maintenance02:40
DocScrutinizeranother nice one: EDSYN GmbH, FL8802:41
DocScrutinizerhttp://de.farnell.com/edsyn/fl88/flussmitteldispenser/dp/876732   02:41
wpwrakyes, this felt pen type is good02:43
wolfspraulpuh, lots of variants02:43
wpwrakdon't get just a bottle of flux02:43
wolfspraulbut I think I get it02:43
wolfspraulwhich pen type?02:43
wolfspraulyou recommend water soluble, and then after tinning you rinse with water?02:44
wpwraka flux dispenser that looks like a felt pen02:44
wolfspraulyou mean just a pen, like in which url?02:44
wpwrakafter tinning, i toss it into the ultrasound bath, where cavitation and water will remove the flux02:44
wolfspraulah, yes02:44
wolfspraulso you cover 100% of the copper in this way, with solder02:45
wpwrakpen like in the url. you can get flux in a number of containers. e.g., 5 l canister would be considerably less convenient :-)02:45
wolfspraulwhich url? there were several02:45
wpwrakboth looked similar02:46
wolfspraulseems clear02:46
wolfspraulpen :-)02:46
wolfspraulso the solder will be your oxidization protection02:46
wpwrakaye. and it'll make sure you already have a bit of solder under the pads when you place, say, a QFN.02:47
wolfspraulany further sealing of the traces?02:47
wolfspraulI mean where you don't want a solder pad...02:47
wpwrakso it's a good thing to do. even if using parts that are easier to solder02:47
wolfsprauland it protects the copper, which is necessary I would think?02:47
wpwrakyou cover all the copper. also the traces.02:47
wolfspraulbut they are still conductive everywhere now02:47
wolfsprauldo you seal this off further?02:48
wpwrakof the copper oxidizes, the oxide is very difficult to solder02:48
wpwraknormally no further sealing02:48
wpwrakif you want to isolate, you can apply acrylic, silicone, PUR, etc., coating at the end02:49
wolfspraulbut you would need to keep the pads free?02:50
wolfspraulor you mean after soldering all parts on?02:50
wpwrakoh yes, isolation would be very last. after soldering, testing, rework, ....02:55
wpwrakbasically when you're ready to forget the board ;-)02:55
wpwrakit's something you rarely need. if you want to protect the board from touch, you may want to make a real case that also prevent mechanical stress of the components.02:56
wpwrakand inside the case, you don't need isolation02:56
wpwrakwell, for low voltages. things change at you approach mains voltage02:57
wolfspraulok we see. one day I want to try with some hardening epoxy02:58
wolfspraulthat should be easy and give mechanical stability as well02:58
DocScrutinizerhmm, considered comlicated02:58
wolfspraullike the blobs you have on cob mounted chips02:58
wpwrakit also makes repair impossible ...02:58
DocScrutinizersome guys claim the shrinking of epoxy will break your circuit02:59
wolfspraulI think there's a lot of epoxies that are relatively easy to mix and use, could be wrong though. won't try this now.02:59
wolfspraulsure could be, that needs trying02:59
wpwrakonce you have that CNC mill, you can make your own cases :)02:59
wolfspraulbut there are serious vendors for these things and I'm sure we wouldn't be the first ones02:59
DocScrutinizerthere are commercialy available varnishes to seal PCB, in spray can02:59
wolfspraulany link?03:00
DocScrutinizerkontakt chemie03:00
whitequark(kontakt) +1 on that03:00
whitequark(HCl) AFAIK if you'd somehow get >35% solution of HCl the HCl itself would instantly begin to evaporate from it until it'd be 35%03:01
whitequark(epoxy) true, this depends on exact type of epoxy03:01
wpwrakwhitequark: i think the limit is around 40%. but yes, you can't get much higher than ~35% unless you're prepared to have a lot more fun :)03:02
wpwraksee also http://en.wikipedia.org/wiki/Muriatic_acid03:03
wpwraknotice how the boiling point goes down as the concentration increases03:03
whitequarkwpwrak: just calculated. it's 45% at 0°C and 42% at 20°C03:03
DocScrutinizertoldya, be careful when the bottle starts smoking when opened ;-D03:04
wpwrakand around here, days with 40 C aren't all that common in summer ...03:04
wolfspraulok I think we got it all03:04
wolfspraulnow the only thing missing is to try and go through03:04
DocScrutinizeryou forgot your vias ;-)03:04
wpwrakwill you go straight for CNC or try with a dremel first ?03:04
wpwrakvia = tiny hole, a matching wire, a bit of solder / solder paste, and numerous curses :)03:05
DocScrutinizeror a rivet03:05
wpwrakmessy and large03:05
DocScrutinizerhollow rivets are rather cool, if you can find matching ones03:06
DocScrutinizerbit you'll need such sophisticated stuff only for RF03:07
DocScrutinizerlike FM-transmitters03:07
wolfspraulgood question [dremel]03:08
wpwrakhmm. i take my chances with a small hole and wire. you can make the vias pretty flat03:08
wolfspraulI will try bottom up, most likely03:08
wolfsprauland buy cheap tools I find on the market03:08
wolfspraulthat's one part of the value for me, with all (seeming) disrespect for the chinese cutting corners everywhere, I want to give myself some time to understand their hacks, no matter how brutal they are :-)03:09
wpwrakhehe :)03:09
wolfspraulif I want to buy something where everybody just shakes heads, I won't be the arrogant "know better" type03:09
wpwrakmanual tools are also good for small corrections.03:09
wolfspraulI have learnt to let the beauty of brutal hacks sink into my mind, even if it takes a little :-)03:09
wolfspraulhow small are the via holes?03:10
wolfspraulif I would use a dremel, you use the dremel for the vias, or a drilling machine?03:10
wolfspraulwhat's the difference actually?03:10
wpwraki use 28 AWG wire for them03:10
wpwrakand the drill is ... looking ..03:10
DocScrutinizer(vias) silver wire is nice for that, it's "soft" so you can easily press it flat on both sides, so it both sticks to the hole and has nice contact and level to the pads03:11
wolfspraulpure silver?03:11
wolfspraulhow does that connect to the copper?03:12
wpwrakyou solder it down03:12
wolfspraulyou mean just heat up the silver? or apply regular solder at the junction?03:12
wolfspraulah you are tinning anyway03:13
wolfspraulthat probably takes care of it03:13
wpwraki do this: 1) apply solder paste on both sides. 2) stick the wire through the hole. it fits precisely, so it's held by friction. 3) solder one side, then the other.03:13
DocScrutinizeryou choose a wire diameter that somewhat sticks to the hole by itself, the cut so both sides have 0.5mm overlength, then flatten it with a pair of pliers or a small hammer and bolt03:13
DocScrutinizerthe solder, of course03:13
wpwrak4) cut off the wire ends.03:14
DocScrutinizerwith normal tin solder03:14
wolfspraulyou use the dremel for drilling the via holes?03:14
wolfspraul(I mean without cnc)03:14
DocScrutinizerthen* DANG!03:16
DocScrutinizerdremel with stand03:16
DocScrutinizeryou don't wanna do this without stand03:17
wpwrakif you have a steady hand and a flexible axis, you don't really need a stand. and the stand may be wobbly if made i china ;-)03:17
wolfspraulI see you internalize the culture here03:18
wolfspraulthe other day I met this foreigner who is working with electronics and complained how you can get anything done if even all test equipment fails03:19
DocScrutinizerdrilling without stand is really really a PITA, esp when you got no pinpoint to center your drill to03:19
wolfspraulif every voltmeter or temperature sensor or *anything* is inaccurate03:19
wolfspraulso he starts to import those things now, to establish at least a testing baseline03:19
wpwrakDocScrutinizer: if drilling manually, you drill after etching. that way, the center holes in the vias guide the drill03:20
DocScrutinizerapropos pinpoints, you *might* consider getting thise in your etching already03:20
DocScrutinizerexactly :-D03:20
wpwrakmaking pcbs, in less than 100 easy steps :)03:21
DocScrutinizerI'm too old for that shit ;-D03:22
wolfspraulI think actually the steps are very simple, it just comes down to guiding someone correctly03:22
wolfspraulit doesn't matter that for every step there are 5 or 10 alternatives03:23
wpwrakyeah, that adds a bit of color ;-)03:23
wolfspraulin fact if you include outsourced fabbing you are actually buying into many different, hundreds, of automated processes at those factories03:23
DocScrutinizerone of the major problems with doublesided is to match both sides exactly03:23
wolfsprauland at least what I do is in no way meant to replace or 'compete' with a factory03:23
wolfspraulbut I do think a very simple process of quickly making pcbs to hookup some chips can be valuable03:24
DocScrutinizeryou might want to drill two adjusting holes even prior to toner transfer03:24
wolfspraulit's also so much better to outsource something after you understand it better03:24
DocScrutinizerbtw when you inspect the transferred toner and find some suspicious sparse covering, you can use an Edding fabric pen to improve the varnish layer03:27
wolfspraulthe edding ink will withstand the etching as well?03:28
DocScrutinizerI used to draw whole boards like that03:28
wolfspraulhow about waterproof pens like for writing on cds?03:28
DocScrutinizerthat's basically this I think03:29
DocScrutinizerof course there are dedicated pens for that as well03:30
wolfspraulwpwrak: ok thanks A LOT!03:36
wolfspraulI think I have the whole thing clear now, give me some time and I will duly report on how it goes :-)03:36
wolfspraulI still think I try with an atben clone, it seems the simplest thing I can use myself03:36
wpwraki'd try some mcu. something really easy to play with.03:40
wpwrakatben is demanding to make. and you have no direct feedback of what's going on.03:40
wpwrakwolfspraul: do you have a scope ?03:42
wolfspraulnot yet :-)03:42
DocScrutinizeroops sorry, tha last link didn't use the edding for etchstop 03:42
wpwrakgood answer ;-)03:42
wpwrak(double-sided) for boards that need high precision, like atben and atusb, i etch one side at a time and cover the other with adhesive tape. that way, i can position the toner transfer paper very precisely.03:46
wpwraki.e., i put the paper on the table, turn the board to the right right, attach the adhesive tape to the back, then put the board such that the outlines on the paper meet the edges of the board, and finally push down the adhesive tape that extends outside the board down on the paper, to fix the board in place. add more tape if necessary, to cover the entire back. then, after etching, i remove the tape, scrub the board to remove all the 03:49
wpwraktape's glue, and repeat the procedure with the other side.03:49
wolfspraula litle hard to follow but I think I get it03:51
wolfspraulthe good news is that all these experiments are quick03:52
wolfspraulno matter how wrong one is, I just fail to see how one can be too unimaginative to not have it worked out after a few days at most03:52
wolfspraulbut of course the various steps add up03:52
wolfspraulshould be ok03:52
wpwrakyeah, relatively speaking. it sucks if you kill a board with a mistake at the very end, though.03:52
wolfspraulwpwrak: if pressed, what would be the turnaround you have now for going from proven and good design files to a pcb ready for soldering?03:53
wolfspraulit sounds like the whole process should not take more than a few hours, even 1 hour maybe if everything is setup and ready?03:53
wpwrakthere are a few things that may need some experimenting. such as the transfer paper. some are very bad. some are almost right but still not good enough.03:53
wpwrakalso, you change the characteristics of the paper when you clean it.03:54
DocScrutinizer>>Das "Geheimnis" ist, dass ich die Platine vorher mit Ajax gereinigt bzw. geradezu "geschliffen" habe und dann das Layout aufgetragen habe. Zum testen übriegens die eine Seite mit Edding 8300 und die andere mit 3000.<< http://www.mysnip.de/forum-archiv/thema/15777/1129065/Platinen+aetzen+_Edding-Methode_+-+Was+mache+ich+verkehrt.html03:54
wpwraktime depends on the required precision and such. let's say 30 minutes for CNC, including setup, then 5 min for cleaning, toner transfer can vary - depends on when i'm happy with a print, maybe 10-30 minutes, then the actual transfer, 5 min. since i usually do two boards in parallel, that would be 10 min.03:56
wpwrakthen 15-20 min for etching, with setup (fetching the acid from the terrace, mixing with peroxide, carrying the box over from the workshop)03:58
wpwrakafter toner transfer also visual control and touch-ups. if the transfer is too ugly, i redo it. after etching also visual control. then toner removal, tinning, maybe some repair, then soldering the components.03:59
wpwraktoner removal is maybe 5 min. tinning too. soldering depends on the complexity of the board :)04:00
wpwrakqfns tend to add a bit more work. oh, did i mention that atben has a qfn ? :)04:00
wolfspraulwhich one, the crystal?04:01
wpwrak(atusb has two. that board is borderline DIY-able, because of all the ground areas)04:01
wpwrakthe RF chip04:01
wolfspraulwpwrak: which dremel tips would I need?04:01
wolfspraulah can't see so well. the chip on my atben (tuxbrain made) looks like it has leads, but maybe not04:02
wpwrakthe crystal also needs some special attention. i use solder paste for it,to make sure these pads really connect04:02
wolfspraulsolder paste?04:02
wpwrakno leads :) only tiny tin corners04:02
wpwrakthe stuff used for reflow04:02
wpwrakyou can also get it in syringes04:02
wpwrak1) solder paste on pad. 2) place crystal. 3) heat with hot air until the solder melts.04:03
wpwrakthe crystal is hard to solder with an iron because you have very little lateral attack surface. the pads are flat and you have the metal case right above. so with an iron, you're likely to solder to the case, which in 50% of all cases not what you want. (the other 50% are ground pins)04:04
DocScrutinizerFYI: [copy from #openmoko-cdevel]04:08
DocScrutinizer[2012-05-15 04:54:52] <pabs3> hmm I got a weird email from sean04:08
DocScrutinizer[2012-05-15 05:02:53] <pabs3> there isn't really much private in it, so here is a pastebin: http://paste.debian.net/plainh/29c671a504:08
DocScrutinizerroh: ^^^04:09
wolfsprauloh I got it04:11
wolfspraulhot air from top?04:11
wolfspraulor you heat up the entire board from the bottom?04:11
wolfspraulDocScrutinizer: Sean is quite chinese nowadays, no? :-)04:12
wolfspraulwords are always on a different, removed, level from actions04:12
wolfspraulit's like a bird singing, for example. just enjoy the flow, think about actions separately. needs some mental relaxation to get used to in meetings... :-)04:13
wolfspraulI am quite OK at it nowadays, I think. I can have a 'conversation' with someone, think about and decide about actions in a totally separate mental thread, and just purely enjoy the good food on  the table as well.04:13
wolfspraulit's like a symphony, words and actions and smiles and good life04:14
wolfspraulnot bad actually04:14
wolfspraulno reason to get worked up - WHILE THE FOOD TASTES SO GOOD!04:14
DocScrutinizerhmm, food04:15
wolfspraulI unsubscribed from the om lists recently, I felt there was not much constructive thought left04:17
wolfspraulonly the same old slogans, almost like from a tape recorder04:17
wolfsprauleven the silence on the Qi channels is more refreshing :-)04:18
wolfspraulwpwrak: what dremel bits do you think are commonly needed?04:27
wolfsprauljust get a wide variety first? anything special to look out for? what are the ones you need the most?04:27
DocScrutinizervia drills04:29
Last message repeated 1 time(s).04:29
DocScrutinizervia drills04:29
wpwrakfirst, you want drill bits. a variety of sizes, from maybe 3 mm down to as small as you can get04:29
wpwrakif you pick a specific wire diameter (for the vias), get lots of drill bits of that size. at least 10. you'll use them up quickly :)04:30
wolfspraulhardened? anything special to watch out for?04:30
DocScrutinizerthen you might find a cutter disk useful04:31
wpwrakthat was my next item ;-)04:31
wolfspraulif you use a dremel to cut the board outline - which bits?04:31
DocScrutinizerthough I always found it's incredibly hard to get straight cuts with them04:31
wpwrakthese discs some in a little cylindrical box. 20 or so.04:31
wolfspraulbbiab - lunch...04:31
wpwrakyou also need the axis bit. with a screw at its end to fix the disc.04:31
wpwrakand then i'd add some bits for grinding and such.04:32
wpwrakdremels are usually available as kit with lots of drill bits, discs, etc. may be best to get one of these. then you have much of the basics covered. plus it creates a sense of empowerment, even if you'll only use 20% of all that stuff ;-)04:33
wpwraki would also get a flexible axis. that way, you don't have to move the heavy and bulky tool but only the much lighter axis04:34
wpwrakincreases the chance of getting straight cuts really straight ;-)04:34
DocScrutinizerre steel wool: I now recall I always used "Wiener Kalk" or some other abrasive cleanser powder04:35
DocScrutinizerlike AJAX, VIM (sic!) :-D04:37
DocScrutinizerooh nope, it was ATA04:37
DocScrutinizernot AJAX04:37
wpwrakwolfspraul: regarding heating the crystal: just from the top. it should be better with also heating from the bottom, but i don't have a good solution for that04:43
DocScrutinizerwarm e-oven plate04:54
wolfspraulgot it all, thanks05:07
DocScrutinizersigh, infobot is under permanent attack since some months now05:20
whitequarkDocScrutinizer: what's with infobot?05:41
DocScrutinizer51offline every few days05:42
DocScrutinizer51some idiots running DOA attacks against it05:43
LunaVoraxHello everyone!10:37
rohDocScrutinizer: bullshit12:09
DocScrutinizerthought so12:09
rohDocScrutinizer: sean is the one not answering important questions. one thing is for sure. when stuff moves to the us, i will not lift another finger anymore.12:09
rohDocScrutinizer: also: all the data on openmoko.org servers is currently under german or bavarian data protection law. means: if the stuff moves to the us, i will wipe all MY personal data (mailboxes, homedirs etc.)12:10
DocScrutinizercould we talk to Harald, as he seems more down to earth with his idea about how the world works12:10
rohDocScrutinizer: so. be aware.12:10
DocScrutinizerroh: sure thing12:11
DocScrutinizerplease wipe my mail dir as well12:11
DocScrutinizerif such a move is pending12:11
DocScrutinizerI'm already working on migrating my main mail addr to some dedicated domain, just pondering how to implement proper spam protection12:14
rohDocScrutinizer: to be fair, i am not in the mood anymore to discuss with such a crowd anymore. no problem if somebody talks to me, or sends me a mail, but the bs going on is nothing i will continue anymore. gismo is basically out already (annoyed and not in the mood for unpaid bullshit)12:14
DocScrutinizerI can feel with you12:14
DocScrutinizerthis rah guy killed my last nerve used for maintaining anything OM related12:15
DocScrutinizerhe had proper help by... Sean?12:15
rohwell.. if you ask for my opinion who was most influencial in killin om over time? sean himself12:15
rohjust answering mails when it is important in less than a week would have been enough.12:16
DocScrutinizerwhat are you currently running for antispam on mail.OM ?12:19
DocScrutinizeror rather, what would you suggest if I were to set up my own mailserver?12:19
rohoeh.. if there is still some part of that working its spamassassin12:19
rohi dont have one on my own servers. i just filter the worst of it out by proper mail setup (whats not a real mailbox cant send me mail without being whitelisted) and the rest is filtered by my thunderbird after imap12:20
rohbasically its a real simple exim + dovecot and saslauthd12:23
wolfspra1lroh: how is raumfahrtagentur going, and the new space?13:21
wolfspra1lI'm really looking forward to visiting one day, maybe only after I move back to Germany though :-)13:22
wolfspra1lone by one I am acquiring some more usable hardware skills :-)13:22
wolfspra1lyou and gismo still working there, and having a good enough stream of paid projects?13:22
Jay7open hw in russia :)13:44
lindi-you just need pirated copy of matlab :(13:48
wolfspraulI though fairwaves was doing pretty good work, didn't know about matlab13:51
wolfspraulmaybe that's a compromise they are willing to make for the time being, but I am pretty sure from the people they would love to go all-open on the tools as well13:51
Action: pabs3 wonders if octave is compatible enough13:51
wolfspraulsure just start using that and if needed improve it :-)13:51
wolfspraula lot probably also has to do with inertia, I know this very well from logic board EDA tools13:52
wolfspraulyoung people < 20yr grow up with tool X or Z and after so many years in the industry, telling them to use something else feels like an amputation of sorts13:53
wolfspraulthen they come up with all sorts of protective 'reasons' why their tool is so much better and the only one that meets "professional" standards, etc. etc.13:53
wolfspraulin reality there may not be much to it, but the degree of efficiency one can achieve with any complex tool over a number of years still precludes a change, for them13:54
wolfspraulI tend to just ignore it nowadays and start with the free tools, ignorance is bliss :-)13:54
wpwrakand free tools mean that they're not likely to die under your hands. vi, LaTeX, and make forever ! :)14:18
wolfspraulah hi :-) I came up with one more question about the pcbs... what is the minimum trace width you feel comfortable with now?14:21
wpwrakhmm, lemme check ..14:21
wpwrak8 mil. leaves a bit of margin for error.14:24
wpwrakso that's ~0.2 mm14:25
wpwraki use a clearance of 8 mil as well but i try to have a slightly wider spacing. e.g., 16 mil clearance for traces where space isn't extremely critical14:28
wpwrakat chips, the spacing may get tighter. e.g., QFN have a pitch pf 0.5 mm / 19.7 mil, sometimes also 0.45 mm / 17.7 mil. but then i fan out to a more relaxed spacing.14:31
kristianpaulwpwrak: yeah 1V2 and 3V3 mix is not very nice tought..15:32
rohwolfspraul: we are still here :)16:03
rohwolfspraul: its hard sometimes, but somehow we managed it so far. mostly it stuff.16:04
roh(which pays the bills)16:04
qi-botThe build was successful: http://fidelio.qi-hardware.com/~xiangfu/build-nanonote/openwrt-xburst.minimal-20120514-1157 17:40
--- Wed May 16 201200:00

Generated by irclog2html.py 2.9.2 by Marius Gedminas - find it at mg.pov.lt!