#qi-hardware IRC log for Saturday, 2014-02-08

DocScrutinizer05whitequark: ideally traces have strictly vertical edges, that's why orthodox tooling uses endmill. In RL though, no trace ever has a vertical edge, particularly not when etching. So if your Z axis is precise enough to ensure gap width, I don't see a problem with using engraving bits00:12
wpwraki'd use an endmill to cut pcbs, though00:18
Action: DocScrutinizer05 prolly too, since controlling Z-axis is not exactly simple00:24
DocScrutinizer05THIS would be something where you *need* feedback00:24
DocScrutinizer05when you for example use ds-sticky to fix your PCB, and you pressed it a 0.1mm tighter at one end of PCB than on the other, then your traces' gaps also are off at least 0.1mm 00:26
wpwrakthat's indeed the sort of fun i had when trying to mill traces. for cutting the pcb, i simply add a bit of overshoot. but with traces, you can only go so far ...00:31
DocScrutinizer05with endmill you should keep in mind that they are tiny and you can only go really slow through material to grind with them. Professional CNC mills use up to iirc 100k RPM00:35
DocScrutinizer05I mean the cutting speed is RPM * 2r * Pi. r(adius) of your endmill is what? 0.1mm?00:37
DocScrutinizer05sounds like a cutting speed like 0.1m/s00:38
DocScrutinizer05for a 10,000 RPM mill. Not really much00:39
DocScrutinizer05when you use a really good cut/travel ratio of 1/10 then you can't move 0.2mm endmill faster than 1cm/s, on a 10000RPM mill00:40
DocScrutinizer05I don't think you can achieve 1/10, I pulled that outa my a....00:41
DocScrutinizer05so more likely you're down to sth like 1mm/s00:41
DocScrutinizer05will still work, but milling your PCB might take a while ;-)00:42
Action: DocScrutinizer05 needs to look up the correct english terms for surface speed of a grinding tool like a saw blade or a endmill, and for the amount the cut advances00:44
DocScrutinizer05heck, I prolly don't even know the german terms for that00:44
DocScrutinizer05just in case I been too fuzzy: when you cut a steel rod with a saw blade, then the saw blade operates at a certain speed in m/s against the rod. And - given a certain pressure you press the blade against the rod and a certain efficiency aka sharpness of the blade - the cut will go deeper in a certain clearly defined ratio for every meter the blade moves across the rod00:47
DocScrutinizer05the ratio is the 1/10 I used in above guesstimate. The pressure is what makes your endmill break since it builds up when you move the endmill through the object to cut00:49
DocScrutinizer05the sharpness aka efficiency is probably getting too low for the fab, so they decided to sell off those used bits00:50
DocScrutinizer05now in industry time is money and they want fast operation of their machines, thus they use 100,000 RPM CNC and pretty sharp mill bits. For you, using the worn bits, it's "no money but lots of time", so you need to adjust your X/Y speed of your CNC down to really slow. The slower the smaller the tool diameter since that directly reduces grinding speed the tool goes ofer the surface to grind00:53
DocScrutinizer05or across* ?00:53
DocScrutinizer05wpwrak: makes sense?00:54
wpwrakyeah, the duller your cutting edges, the slower you have to go00:58
DocScrutinizer05btw pressure is in force/area where area is the width of your tool * depth you cut into the PCB, so 0.2mm (dia of endmill) * maybe 0.15mm (depth of trench in PCB to cut)00:59
wpwrakwith a factory-new 12 mil (0.3 mm) at 6000 rpm, i didn't dare to go faster than 0.5 mm/s. you can probably go faster but each wrong guess costs some USD 15 ...01:00
DocScrutinizer05that's why I thought a real feedback of force on tool bit would be really useful01:01
DocScrutinizer05you intentionally break one bit to caibrate the sensor, and that's the last bit you ever broken on that CNC machine01:02
DocScrutinizer05well, at least for that particular type of bit01:03
wpwrakfamous last words ;-)01:03
DocScrutinizer05no matter what you cut and how deep you cut and how sharp the bit and how fast the spindle, you always can limit the XY-advance to a safe amount01:04
DocScrutinizer05just your "break distance" of your CNC has to be shorter than the elastic deformation the bit allows01:05
wpwrakhmm, actually you can't because there are other types of mishaps that can break your mill. but yes, keeping the speed reasonably low prevents having to replace mills all too often01:05
DocScrutinizer05to me it feels more like "insanely unbearably low", but yes ;-)01:06
wpwrakexcessive speed can also cause vibrations that make the cut uneven01:07
DocScrutinizer05well, after a week even moderately complex PCB should be finalized01:07
wpwrakoh, one common mistake is to get Z wrong. or to forget about some obstacle, clamp or such. then the mill rushes into whatever at full speed because it things it has no contact with the workpiece.01:08
DocScrutinizer05probably a very good tactics is to use a 1mm or even 3mm endmill for everything that doesn't need to get any finer than that01:08
DocScrutinizer05sure, that's human error01:09
wpwrakand then sometimes parts of a piece come off and strike the mill. or, worse, stay attached to it.01:09
DocScrutinizer05that's bad01:09
wpwrakyes, always pick the largest mill that can do the job :)01:09
DocScrutinizer05and you should try to find tool path that avoids creating such loose blobs01:10
wpwraksometimes the toolpath is fine but the adhesive is too weak01:10
DocScrutinizer05I guess advance speed goes up diameter^4 or sth like that01:10
DocScrutinizer05higher circumference speed, higher force allowable01:11
wpwrakluckily, my mill detects such things fairly quickly. so it must have some sort of sensor.01:11
wpwrakone limiting factor is the mill's torque and the amount of vibration the talk can tolerate01:12
DocScrutinizer05200W should create enough torque01:13
wpwrake.g., i wouldn't try my 1/8 in (3.2 mm) mill on a PCB01:13
wpwrakyeah, whitequark's machine is pretty powerful01:13
wpwrakmine has only 10 W (in the spindle motor)01:14
DocScrutinizer05that's a bit low01:15
Action: DocScrutinizer05 wonders how much has his Proxxon "dremel"01:15
wpwrakwell, it's intended for light work. also, a weak spindle motor means a lower chance for self-disassembly ;-)01:16
wpwraki.e., the sooner or the later we'll hear whitequark curse about the mill cutting into the table ;-)01:17
DocScrutinizer05"look, I can shoot away the floor as well!" ?01:17
DocScrutinizer05that's why you *always* use a 10mm decent victim material 01:18
wpwrakwhat we need is an industrial robot (the kind that has an arm with many degrees of freedom) with a high-powered laser cutter ;-)01:19
DocScrutinizer05since ~2years I'm googling for really powerful cutter lasers every now and then01:20
DocScrutinizer05haven't found anything better than "cuts plastic sticky foil" so far01:21
DocScrutinizer05really good IR laser (LED) >100W is hard to find, even new from manuf01:22
DocScrutinizer05at some shipyards the not only cut 50mm steel sheets by laser, they even weld whole ships by laser robots01:24
DocScrutinizer05those are awesome tools, really :-)01:24
DocScrutinizer05a few 100kW01:25
DocScrutinizer05basically those shipyards became giant makerbots during the last few decades01:30
DocScrutinizer05I guess they wouldn't find the right focus and PWM adjustment to make a PCB though ;-)01:31
wpwrakmaybe you should make friends there. i'm sure they discard old equipment every once in a while ...01:32
DocScrutinizer05the precision is probably in the mm range at best01:32
DocScrutinizer05hardly ever they discard those lasers01:32
DocScrutinizer05just like Queen Mary doesn't discard the engine01:33
DocScrutinizer05I guess the laser weighs dozens of tons01:34
wpwrakif they upgrade to a new generation of machines, why would they keep the old ones around forever ?01:34
wpwrakah, that kind :)01:34
wpwrakmeanwhile, you may like this: http://www.laser-gadgets.com/pulse_laser_gun.php01:34
wpwraknot what you crave but at least can do some depth01:35
DocScrutinizer05(melts tungsten!)  W*T*F?!01:35
DocScrutinizer05incredibly nice, I planned to build exactly that for years01:47
DocScrutinizer05I wonder what he's using. CO2 gas tube?01:47
DocScrutinizer05can't think of anything else01:48
DocScrutinizer05I really wonder about beam divergence01:49
DocScrutinizer05and I really wonder how he creates that allegedly 1MW01:52
DocScrutinizer0580-100 Joules @ 350-400 Volt    --- ???? how???01:53
DocScrutinizer051J = 1VAs01:54
wpwrakmake is 1 us, so you only need 1 W continuous per MW  pulsed ;-)01:55
DocScrutinizer05-> 0.25As01:55
DocScrutinizer05I don't see the slomo showing a 1uS pulse though01:55
DocScrutinizer05maybe 1ms01:56
DocScrutinizer050.25As/400V = ok, 625uF01:57
DocScrutinizer05assuming he thinks the flash could burn down to 0V in buffer capacitors01:58
wpwraki think the critters work at some kV01:58
DocScrutinizer05100Ws / 0.0001s = 1MW01:59
DocScrutinizer05so, ignoring all the false assumptions and all the ignored efficiency loss, he actually might create a bruto 1MW pulse laser02:00
DocScrutinizer05netto maybe 100W02:00
DocScrutinizer05,aybe even 1kW02:01
rohco2 doesnt melt metal02:03
DocScrutinizer05he's stating >>Caution: HIGH VOLTAGE ! Energy storage stores 80-100 Joules @ 350-400 Volt !<<02:03
DocScrutinizer05which is in line with usual electron flash02:04
rohone usually uses not 10.6µm (co2) but 1µm (1064nm)02:04
rohNd:YAG is what one wants for metal02:04
DocScrutinizer05that starwars phaser laser pulse gun doesn't claim it's particularly suited for melting metal02:05
DocScrutinizer05and I really have severe doubts about his claim >>(melts tungsten!)<<02:06
DocScrutinizer05I dunno what's used in shipyards to cut those 50 or 100mm steel sheets like cake02:08
DocScrutinizer05http://www.industrial-lasers.com/articles/2002/04/lasers-in-us-shipbuilding.html  talks about CO2 lasers nevertheless02:10
rohDocScrutinizer05: plasmacutters02:13
DocScrutinizer05I know plasmacutters exist02:13
DocScrutinizer05I even used them, fun stuff02:13
DocScrutinizer05fixed them02:14
DocScrutinizer05(rectifier broken)02:14
rohjup. either that or use a waterjet02:14
DocScrutinizer05I don't. shipyards use laser cutting nowadays02:14
rohanything else for cutting metall is usually for thin sheets (less than 5-3cm)02:14
DocScrutinizer05and they do for cutting really think steel sheets, and also for welding02:15
rohthe article above talks about welding mostly02:15
rohlasers have some disadvantages at price end.02:15
rohand one doesn usually need the precision02:16
DocScrutinizer05seems increased precision is outweighing that02:16
DocScrutinizer05aiui nowadays 100m+ ocean liners are completely built on CNC laser cutting and welding02:17
DocScrutinizer05portal XYZ actuators that move a bot arm with some more degrees of freedom to anywhere of the cross secion of that ocean liner02:18
DocScrutinizer05and for sure laser cutting of steel sheets of several meters length and height, and up to 100mm thickness02:19
DocScrutinizer05to cut out appertures for doors and windows, and so on02:20
DocScrutinizer05then weld the cut sheets into place, also with laser02:20
DocScrutinizer05I have no detailled info, just a TV report about contemprary laser usage02:21
whitequarkDocScrutinizer05: (unbearably slow) yes, this is exactly my concern, safe surface speed for this 0.2mm endmill means a very trivial pcb routes for like 1.2 hours06:37
whitequarkwhich is absurd06:37
DocScrutinizer05well, go for 100,000 RPM then ;-)06:38
DocScrutinizer05or don't cut trenches with 0.2mm when you could cut them 1mm wide as well06:39
whitequarkwell... a spindle for 60000 rpm would set me back about $70006:39
whitequarkwater cooled one even06:39
whitequarkhowever it is also frequency controlled and as such needs some weird kind of inverter or something, I dunno06:40
DocScrutinizer05I think it's a common best design practice to not use 0.2mm clearance between traces except where absolutely needed06:41
whitequarkDocScrutinizer05: tqfp pads06:41
DocScrutinizer05hlw long are the cuts you need for those?06:41
whitequarkone pad is about... 4mm long cut? multiply by 32 or 64 or w/e06:42
DocScrutinizer05I can't see a CNC mill take 1.2h for a TQFP footprint06:42
whitequarkit's a whole board06:43
whitequarkthe CAM I'm currently using is unable to mill the board with several different tools06:43
DocScrutinizer05that's the problem then06:43
whitequarkbtw for the 0805 resistors the gap is .3mm06:44
whitequarkbasically I think you need "roughing" step and "finishing" step like you would for any other cnc workpiece06:44
whitequarkfor pcbs06:44
whitequarkbut I know of no CAM that does that...06:44
Action: DocScrutinizer05 wonders if you actually could *print* PCBs06:48
DocScrutinizer05like - use silver varnish, then burn in at 350°C06:48
DocScrutinizer05it seems some CIR remote PCBs already get built that way - at least partially06:50
DocScrutinizer05they however use carbon varnish it seems06:51
DocScrutinizer05also print their resistors06:51
DocScrutinizer05and even jumpers across traces06:51
DocScrutinizer05maybe those jumpers are just low-R resistors06:52
Action: whitequark did a fun check for the accuracy of his cnc machine07:08
whitequarkI took a chunk of PCB and milled the laminate away, leaving just the bare copper07:08
whitequarkseems to have worked out very well07:09
whitequark... grh, wpwrak can rejoice: I've just milled into my table a little bit :/07:19
whitequarkDocScrutinizer05: wpwrak: is it important to use deionized water for etching/developing solution, or is regular boiled water OK?07:21
DocScrutinizer05I'd think reasonably clean tap water is ok07:22
DocScrutinizer05for H2O2 you don't want to add impurities of any kind usually07:22
whitequarknay, H2O2 isn't my cup of tea07:22
DocScrutinizer05but then, who would mix H2O2 with H2O?07:22
DocScrutinizer05ooh right, prolly illegal in Russia07:25
whitequarkH2O2? yes, hard to obtain07:26
DocScrutinizer05use Plutonium instead ;-P07:26
whitequarkbtw have you ever used "liquid tin" ?07:26
whitequarkI've bought a bottle to try it out 07:27
DocScrutinizer05liquid silver here07:27
whitequarkit's a chemical tinning solution07:27
DocScrutinizer05ooh that one07:27
whitequarkyou put the pcb inside for 20 minutes and tin precipitates from the solution07:27
whitequarkon the copper07:27
DocScrutinizer05yeah I think I tried that once a 40 years ago07:27
DocScrutinizer05result was some metallic dirt on PCB that sticked to the fingers when touching it, instead of to the copper07:28
whitequarkwell chances that in those 40 years they managed to build it better07:28
whitequarkor maybe not, no idea really07:28
DocScrutinizer05I guess carefully drying the PCB and tin without touching surface, then spraying PCB with flux, then "curing" the whole thing with a blue welding flame....07:31
DocScrutinizer05but then, you probably could reach better results with solder paste07:32
whitequarkwell, the shop had a demo board tinned with this solution, it looked pretty rad07:32
whitequarkdefinitely not "sticked to fingers better than to copper"07:33
whitequarklol I seriously doubt that07:33
whitequarkthose guys (gals actually) have very high-quality supplies and I shop there for years07:33
DocScrutinizer05prolly some current can do wonders anyway07:34
DocScrutinizer05ooh, you say they prepared that  themselves?07:34
DocScrutinizer05well, then...07:35
whitequarkanother funny thing: I've bought several aerosols by cramolin there. I've not found a single place on the web to buy them, at least in single bottles07:35
whitequarkCramolin, have you heard it? it's a .de company07:36
DocScrutinizer05not unknown that companies cheat though, like acme solder co winding stannol solder wire on their acme hub for doing the demo video07:36
whitequarkmake very nice (and absurdly expensive) aerosols. flux-off is particularly nice but they have several dozens of them for all imaginable purposes07:36
DocScrutinizer05never heard of cramolin07:37
DocScrutinizer05here we call that "Kontakt Chemie"07:37
DocScrutinizer05dunno if it's a different localized name for same gue07:37
whitequarkooooh yes. exact same package design, guess it's a different name07:38
whitequarkalso explains why I wasn't able to find it anywhere07:38
DocScrutinizer05aah Kontact is CRC actually07:39
DocScrutinizer05from CRC to CRamolin is not a far way to go, eh?07:41
DocScrutinizer05http://www.kontaktchemie.com/KOC/KOCproducts.csp?CSPToken=bLhmMNhCqCm_qDqZf_5$iTV_Ef3UzIEfD1KIlpaicbI-  is quite nice07:45
DocScrutinizer05(CRC) e.g. click "IDS" on http://www.kontaktchemie.com/KOC/KOCproductdetail.csp?product=MULTI%20FOAM%207707:49
DocScrutinizer05ingredients: ... potassium hydroxide; caustic potash ... Phosphoric acid ...07:51
DocScrutinizer05dang, that make a LOT of sense ¡07:52
whitequarkhighly active, duh!07:52
whitequarkoh, you mean an acid and a base at the same tim07:53
whitequarkwait, where did you find those ingredients? I can't find any in the pdf at "TDS"07:54
whitequarkno such link07:57
DocScrutinizer05that page throws error from that linkl07:58
DocScrutinizer05damn JS07:58
DocScrutinizer05from main page click on "multifoam 77"07:59
DocScrutinizer05MULTISCHAUM 77 12x400 ML de,fr  >>> IDS07:59
DocScrutinizer05IDS is a link07:59
whitequark... okay, there is no multifoam 77 link on the main page08:00
whitequarkno "multifoam" or "77" at all08:00
whitequarkoh, if I switch to DE then there is08:00
DocScrutinizer05it's there in english as well08:01
whitequarkI need to switch "language on label" to DE, not site language08:01
DocScrutinizer05but links never work as expected08:01
whitequarkanyway, I think I understand the reason08:02
whitequarksee, it's "ingredients", not "components". they wrote what they mixed in the solution, not what results08:02
whitequarkso perhaps some of the components only are soluble in acidic environments, but after they're mixed together, they form something else which doesn't care about pH08:02
whitequarkand at that point you can add your base08:03
DocScrutinizer05umm, what? 08:03
DocScrutinizer05they wrote? where?08:03
whitequark"List of ingredients"08:03
whitequarknot "components"08:03
DocScrutinizer05yeah, sure08:04
DocScrutinizer05anyway Kontaflon 85 is my personal recommendation for lubricant for special cases. Really amazing stuff08:05
DocScrutinizer05sprayed the board of my pinball machine with it, and after that the balls were twice as fast, and no more wear on the paintings and varnish08:06
whitequarkyou have a pinball machine?08:07
DocScrutinizer05I had08:07
DocScrutinizer05quite some time ago08:07
DocScrutinizer05I lost everything, several times08:07
whitequarkI recall... li-ion fire08:08
DocScrutinizer05:nod:  but there the pinball machine already been gone08:08
DocScrutinizer05yesterday I seen a TV report about those old machines, and I pondered getting one again08:09
DocScrutinizer05console games never got the hook in me, but pinball... I started playing when I been 6 years old, or even earlier08:10
DocScrutinizer05I used a beer crate to stand on when playing08:11
DocScrutinizer05and after some 30min some of the personal of that bowling noticed me and chased me out08:12
DocScrutinizer05a game been 10 Pfennig back when08:12
DocScrutinizer05ooh, btw s/LiIon/NiMH/  though that's a suspicion only08:17
DocScrutinizer05NiMH seem more dangerous to me than LiIon08:18
whitequarkoh okay08:18
Action: whitequark has just peeled the film from a polycarbonate sheet08:18
whitequarkit is beautiful.08:18
DocScrutinizer05since they have no good emd-of-charge detection properties, I seen them heat up insanely high several times, in chargers08:19
DocScrutinizer05the hotter those NiMH get, the lower the tempreature08:19
DocScrutinizer05so when the charger misses the delta-V, it goes al the way till disaster08:20
DocScrutinizer05the hotter those NiMH get, the lower the voltage08:20
whitequark(misses dV) unless it has a heat sensor, and it better have one!08:20
DocScrutinizer05fastchargers are supposed to stop when they detect decay of voltage caused by battery heatup08:21
DocScrutinizer05yeah, pretty few have, and for sure the vacuum cleaner that prolly started that fire had any such fancy stuff08:22
DocScrutinizer05it actually just had a series resistor and a 5mm barrel connector for external power supply08:22
whitequarkdo you have any appliances not posing a fire hazard? :D08:22
DocScrutinizer05yeah, my smoke detectors ;-P08:23
whitequarkokay, I'm off to get labeling paper, deionized water, more airtight containers and stuff08:23
whitequarkfortunately it's all within 5 subway stops so not going to take too much time08:24
DocScrutinizer05wich surprisingly reminds me to get a CO2-fire-extinguisher08:24
DocScrutinizer05the power extinguishers are a disaster in themselves08:24
DocScrutinizer05you extinguish the flames, then you tear down the building since the powder ruined everything08:25
whitequarkcould skip extinguishing the flames then08:26
DocScrutinizer05thus: CO2 extinguisher08:26
DocScrutinizer05(halon extinguishers are forbidden - a shame)08:26
whitequarkare they? my father installed a bunch on a power plant here in moscow08:27
whitequarkwell, maybe .de regulations are stricter08:28
DocScrutinizer05I just found some, for exorbitant pricetag, exclusively approved for use in air- and spacecraft08:41
DocScrutinizer05awesome short forum chat (sorry, german) - the last comment is golden http://www.audifieber.de/audiforum/threads/8850-Feuerlöscher-Halon-na-und08:47
whitequarkDocScrutinizer51: by the way, I've looked again at cans in the shop and they're called "kontact chemie" here too11:59
whitequarkI guess they rebranded themselves from "cramolin" even in .ru11:59
DocScrutinizer05air 67 is a monster ;-)12:00
DocScrutinizer05feels like 8 bar12:00
whitequarkI've bought some deionized water12:01
whitequarknot as much because I don't trust tap water, but rather to ensure 100% reproducibility12:01
DocScrutinizer05(air) costs more than gold though. Realy only good when you absolutely can't use other cheaper options12:04
whitequark$3/L... if I need a bit more of it, it's probably wise to invest in a deionizer12:04
whitequark(air) *everything* they make costs more than gold :D12:04
whitequarkbtw, it's not actually air, it's propane+butane mix12:04
whitequarkdunno why they call it "air"12:04
DocScrutinizer05yep, i know12:04
DocScrutinizer05err, it has no "flamable2 warnings12:05
whitequarkmine has12:06
whitequark"flammable material: 100.0% wt."12:06
DocScrutinizer05hmm, this http://www.kontaktchemie.com/KOC/KOCproductdetail.csp?product=DUST%20OFF%20HF not12:10
DocScrutinizer05nfc what it is12:10
DocScrutinizer05whitequark: which one exactly do you have?12:14
DocScrutinizer05honestly, that website SUCKS! >> CSP-Request-Objekt-Inspektor<< rotfl!12:17
whitequarkDocScrutinizer05: I think it's "DUSTER", not sure which number12:18
whitequarkI'll tell you once I get home12:18
DocScrutinizer05this one says "not flamable when used according to instructions" - which is a pretty poor joke12:19
DocScrutinizer05in english: >>Non-flammable* formulation. * criteria according aerosol directive.<<12:21
DocScrutinizer05while DUST OFF 360 SUPER says >>A non-flammable formulation in all conditions. <<12:23
DocScrutinizer05>>Designed for critical applications, where 100% safety is an absolute must.<< lol12:23
DocScrutinizer05DUST OFF HF (HIGH FLOW) (mine): >>. A non-flammable pressurised gas, designed for applications where absolute safety is a must, it can even be used on energised equipment, when there is a risk for discharges.<<12:24
whitequarkI'd be really wary of "non-flammable*"12:28
DocScrutinizer05this site is so abysmally bad. incredible. Select "English" on top right. Tick "Duster Spray" in left side menu. With "Language on product label ": German you see 6 products. with English you see only 312:29
DocScrutinizer05OOOH, on PRODUCT label. OMG12:32
DocScrutinizer05"sorry, this spray is not available in english language" lol12:32
DocScrutinizer05mhm, now i got it, finally12:36
DocScrutinizer05tetrafluoroethane 75-10%012:36
DocScrutinizer05Dimethylether 5-10%12:37
DocScrutinizer05nfc why they need 5-10% dimethylether in that stuff12:37
DocScrutinizer05mine is tetrafluoroethane   with 5..10%  1,1-Difluoroethane12:39
Action: DocScrutinizer05 notices much Fluor around him lately12:41
DocScrutinizer05whitequark: I don't think the Kontakt chemie stuff ever had Butane/Propane in their duster sprays12:50
whitequarkI've dissolved 250g of (NH4)2S2O8 and the water is much much colder13:04
whitequarkspecifically 9°C with room at 24°C13:05
whitequark8° even13:05
DocScrutinizer05normal, no?13:07
whitequarkI remember this effect from my classes, just wasn't expecting to observe it13:07
Action: DocScrutinizer05 forgot to get milk for the weekend, with all the Kontakt chemie stuff :-S13:07
whitequarkit's just 3pm or 2pm there13:08
DocScrutinizer05yep, but my shopee closing at 14:00 the latest13:08
whitequarkthat is inconvenient13:08
DocScrutinizer05now I have to walk 1000m to get milk of inferior quality :-(13:08
whitequarkisopropanol *stinks*13:09
whitequarkI would even say reeks13:09
DocScrutinizer05I once worked for a cleaning service where we cleaned a whole school's carpets (YES!), and the water vacuum needed iso spraying every 5 min to destroy the foam building up13:10
DocScrutinizer05then continue vacuuming and dpread the fumes into the air13:11
DocScrutinizer05spread even13:11
DocScrutinizer05was real fun :-S13:11
whitequarkI wonder if it's intentionally flavored to make sure no one drinks it13:12
DocScrutinizer05no, i'm sure it really smells terrible13:12
DocScrutinizer05genuine stinker13:13
DocScrutinizer05hmm, maybe not: >>Isopropyl alcohol is denatured for certain uses, in which case the NFPA 704 rating is changed to 2,3,1.<<13:18
whitequarkwiki says it has a peculiar odor13:27
whitequark"more pungent than ethanol"13:28
whitequarkpungent indeed13:28
DocScrutinizer05LOL  >>The chewing of cordite, as a form of chewing gum was far from unknown in the late 19th and early 20th centuries. The sweet taste made it attractive, and it gave the user feelings similar to those produced by alcohol. (Due to its explosive qualities, however, several fatalities were reported, from chewing too strenuously.(Ref: http://trove.nla.gov.au/ndp/del/article/3281990 among other sources.))<<13:32
DocScrutinizer05I wonder wtf goes on with that stuff. I thought nitroglycerine was toxic in all but the smallest dosages13:41
whitequarkhrm, I wonder13:45
larscexploding chewing gum?13:58
whitequarkhrm, I might want to get glasses out of proper glass and not polycarbonate14:04
whitequarkwith all this UV and stuff14:04
viricI hate non-glass glasses14:06
viricI only once had non-glass glasses, and in a week, they were scratched.14:06
whitequarkthese are quite scratch-resistant, I couldn't scratch them once in about three years14:07
whitequarkmaybe foru14:07
viricMaybe I'm careless enough about glasses, that I need glass ones14:07
viricMy brain learned that I can place them anywhere anyhow, just not hit them14:07
viricand that's fatal for polycarbonate.14:08
whitequarkI'm more worried that they're made from the same material I use for exposing PCBs specifically because it's UV-translarent14:08
whitequark(fatal for polycarbonate) maybe your polycarbonate is shitty or something14:08
viriccan be14:08
whitequarkbecause I never cared to think where I place my glasses and nah, they're smooth14:08
viricI didn't know about the UV14:08
whitequarkI'm actually breaking the frame before scratch or break the lens14:09
viricI see, quite the opposite of my experience14:09
whitequarkokay, now I made a 5% solution of NaOH and it is pretty damn hot14:33
whitequarkI wonder why is enthalpy of dissolution so different14:34
whitequarkin sign even14:34
DocScrutinizer05I have another interesting question for you: what happens to Cu2C2 when something happens. I don't see any gas or sth in there14:44
whitequarklike Cu=C=C=Cu ?14:44
whitequarkor Cu-CaC-Cu14:45
DocScrutinizer05err Cu(II)14:45
whitequarkregardless of it, this should be really unstable if it even exists14:45
whitequarkok, then the former14:45
DocScrutinizer05nah! Cu(I)14:45
whitequarka bit less weird14:46
DocScrutinizer05Cu(II) is even more instable14:46
whitequark"A stable and stoichiometric Cu2C2 phase in nanoparticle form has been synthesized using activated reactive evaporation technique."14:46
whitequarkyeah, copper carbides apparently exist14:46
whitequarkokay, so what do you want to learn?14:46
whitequark>that easily explodes when dry.14:47
DocScrutinizer05hmm, *H2O14:47
whitequark>< whitequark> regardless of it, this should be really unstable if it even exists14:48
DocScrutinizer05sure, but what *happens*?14:48
whitequarkokay, when you mix carbides with H2O you get acetylene and metal hydroxides iirc14:48
whitequarkCu2C2 + H2O -> Cu2O + H2C214:48
whitequarkthen Cu2O + H2O -> ...14:48
whitequarkin reality it happens in one stage of course14:49
whitequarkactually, hm14:49
whitequarkno, it'll just precipitate as Cu2O because it's not soluble in water14:50
whitequarkso acetylene and copper(I) oxide14:50
DocScrutinizer05haha! >>Thermal decomposition of copper acetylide in vacuum is not explosive and leaves copper as a fine powder at the bottom of the flask, while depositing a fluffy very fine carbon powder on the walls.<<14:52
whitequarkyup, I guess it's exploside because it results in very fine pyrophoric particles14:52
whitequarklike, it's a self-propagating volumetric explosion14:53
DocScrutinizer05must be extremely hot14:53
DocScrutinizer05actually to me that sounds like it evaporates carbon14:55
DocScrutinizer05the german wikipedia has much less info14:56
DocScrutinizer05>>it is interesting as a curiosity because it is one of the very few explosives that do not liberate any gaseous products upon detonation.<< been completely missing in german wikipedia. That's why I wondered what happens14:57
DocScrutinizer05when you would pack it without H2O and without any air and place it into a containment, it wouldn't make that containment burst, right?14:59
whitequarkI don't think so15:00
whitequarkbut, there is always some air15:00
whitequarkunless you work hard to remove it all15:00
whitequarkactually, no, I think it still could burst... chances that the result products are much less dense than source15:01
whitequarkI don't know shit about crystallic lattices of former and latter, but intuition says it'll be less densely packed afterwards15:01
DocScrutinizer05hah, so it might "explosively" expand by - say - factor 2 :-)15:02
DocScrutinizer05which might have whole new usecases since the expanding material isn't gaseous15:02
DocScrutinizer05it might be way more effective on solid materials like steel etc than any "usual" explosive15:03
DocScrutinizer05while same time it should have a really low explosion radius15:04
DocScrutinizer05you probably could blast a 1mm hole into usual glass with it15:05
Action: DocScrutinizer05 makes notice to get copper(1)chloride, ammonia, and some good old carbide15:12
wpwrakCNC milling was yesterday. now you'll introduce CNC precision explosive deposition ;-)15:30
whitequarkhuh. I wasn't too greedy with chemicals this time and the results are fascinating17:20
whitequark5% NaOH removes resist *very* fast17:21
whitequark30% etchant also works marvelously17:21
wpwrakso it's back to chemistry then ?17:23
whitequarkfor now, since the cheap endmills haven't arrived yet (and won't get there any time soon), and I'm sure as hell not going to buy a dozen of $15 ones17:24
whitequarkwell, there's the engraver trick, but I couldn't find engraver bits which ship fast as well17:24
whitequarkplus either way it is so very slow17:25
whitequarkI'll eventually compare chemistry with milling17:25
whitequarkanyway. most of my grief was caused by the fact that I used USSR-formula photoresist, and it is well known (as I'm aware now) for being ridiculously shitty17:25
whitequarkI'm now trying with proper imported resist17:26
whitequarkharumpf. I need something like this: http://www.ebay.com/itm/331092658541 but cheaper17:26
wpwraki suspect that chemistry wins in the end. milling has the enormous benefit that you can make traces and cut the pcb in the same process, thus eliminating any offset, but that's about all it has going in its favour17:26
Action: whitequark nods17:27
whitequarka combination of hot plate and stirring is ideal for etching... now only where to get that for a sane price17:27
whitequarkand preferably NOT with 110V input yet again17:28
whitequarkwpwrak: http://www.ebay.com/itm/25143579478117:29
whitequarkdoes this look like a disaster or is it just me ?17:29
whitequarkoh wait, no t° regulation17:30
wpwrakhmm, my catv link is very sick. 58% packet loss to the next hop17:31
wpwraklet's see if resetting the modem helps ...17:33
wpwrakkewl. that did the trick :)17:34
wpwrakwhitequark: maybe find a source for HCl. then you don't need to cook your acid17:36
whitequarkokay, etching is *very* slow. I'm doing it for 18 minutes already17:36
whitequarkthere's a lot of bubbles, so it is likely due to the fact it's not being stirred17:37
whitequark(HCl) eugh. not really wanting to work with it.17:37
wpwraki suppose a bottle of vodka + a 5 liter of HCl from your local industry supplies store may be cheaper than equipping a chemical work-around lab :)17:37
whitequarkso far every chemical I need is a little bit corrosive, but that's it. hcl is outright dangerous.17:38
wpwrakof course, already 1 l would last you for years. if they have it in such small quantities :)17:38
wpwrakyes, HCl is a little corrosive. i noticed when i tried to store it under the kitchen sink ;-)17:38
wpwraknow it has a nice safe place outside17:39
wpwrak(bubbles) you have to stir/move the pcb ... if you just let is sit there it's likely to take a day or so ... and etch at places you never thought the acid could enter17:40
whitequarkyeah, that pisses me off17:42
whitequarkhence search for magnetic stirrer17:42
wpwrakthat's why a fast acid is convenient. you can make HCl+H2O2 about as fast as you can handle.17:42
whitequarkactually a nonheated one would likely do the job, that's much cheaper17:42
wpwrakmost of the non-HCl-based processes are slow at ambient temperature17:43
Action: whitequark wonders what is the motive of wpwrak advising him to use more dangerous chemicals ;)17:43
wpwrakHCl isn't *that* bad17:43
whitequarkwell, 35% hcl is17:44
whitequarkI'm not working with it again unless I absolutely need that17:45
wpwraki.e., i'm not telling you to use a 1000 liter basin of FOOF heated to 1 C below boiling temperature ;-)17:45
larscand with sharks swimming in there ;)17:45
larscradioactive sharks17:45
wpwrakwith lasers17:45
whitequarkI don't think *anything* can swim in FOOF17:46
whitequarkliterally anything17:46
whitequarkI'm not even sure what are you going to use for storage at 1°C below boiling temp17:46
wpwraki guess it all depends on the time scale :)17:46
wpwrakdirected gravitational fields ?17:46
wpwrak(HCl) i guess it depends on ventilation. if you have good ventilation and can store it outdoors, you should be fine.17:47
whitequarkI live in an apartment without a balcony17:48
wpwraki.e., i don't see any unusual amount of corrosion in the area where i do my etching. and i keep the etchant (which contains HCl at a low concentration, certainly < 10%, probably < 5%) around for reuse17:49
wpwrakthe pure HCl, on the other hand, gets stored outside, so the vapours can escape17:49
wpwrakah, no balcony complicates all this17:50
wpwrakmaybe find some chemist you can ask about ways to store chemicals indoors18:00
whitequarkI can already tell you the answer: "don't"18:03
whitequarkeither that or they're a really bad chemist :]18:03
wpwraknaw, it's HCl. it's used everywhere.18:06
whitequarkwell, not in places people live18:06
wpwrakwell, you wouldn't want to live in a microwave oven either, yet you may have one in your kitchen ...18:08
whitequarkunlike HCl, microwave oven can be turned off :)18:09
wpwrakyou can always neutralize that acid :)18:09
whitequarkabridged-advice-wpwrak? :D18:10
wpwrakoh, plan B to bribing a chemicals supply store would be to google for household chemicals that contain HCl. some may have it in relatively pure form. http://hpd.nlm.nih.gov/cgi-bin/household/search?tbl=TblChemicals&queryx=7647-01-018:12
wpwrakespecially toilet cleaners seem to be pretty potent in this regard18:13
whitequarkthat fails my "repeatability" requirement, who knows what else is in that can18:16
wpwrakit's usually written on it. but yes, you'd have a process that largely depends on a specific set of products. of course, since they all try to accomplish the same, the formulas may be very similar.18:17
wpwrakmy main concern would be additives that react with peroxide. so another question for the chemist you should befriend18:18
wpwrakanother problem would be the thickener. that's probably the main additive. but since you'll dilute the critter with peroxide anyway, is should become a bit more liquid, too18:22
whitequarkno, I'm definitely not using a process so hard to reproduce exactly18:23
whitequarksince reproducibility here is my #1 goal18:23
wpwraknot that hard. buy toilet cleaner X, add the usual peroxide. chances are you'll be able to get cleaner X for a very long time. besides, you need only small quantities. so a bottle will last a good while, even if it's less efficient than pure HCl18:24
whitequarkit's not as much about using same process for X years, as for understanding it thorougly and sharing it18:25
wpwraki think you'll want to look for customer comments on toilet cleaners, comments where people say they had some nasty stains and already tried a number of cleaners that didn't work18:25
wpwrakwell, you could share it in russia :)18:26
wpwraklet's see if anyone has done that before ...18:26
whitequarkmost pipe cleaners here use NaOH anyway18:26
whitequarkand it has very nasty dark color due to it being ridiculously dirty18:26
wpwrakyup :) http://www.instructables.com/id/Etching-a-circuit-with-toilet-bowl-cleaner/18:26
whitequarkalso, the comments on your instructable say it doesn't work very well18:28
wpwrakyou want something that removes rust and lime18:28
wpwrakwell, the one he used is only 20%. and maybe he used weak peroxide, too18:28
whitequark"only" 20% acid18:29
whitequarkit's more than half its max concentration18:29
wpwrakand he didn't stir18:29
wpwrakand he uses metal pliers to remove the board. yeah ;-)18:29
whitequarkso we're at stirring again. and I found a heating stirrer locally for $13018:29
whitequarkso will prolly just buy that18:29
whitequarkand it would work with *any* etchant I'd want to throw at it18:29
whitequarkbecause they all damned need stirring18:30
whitequarkand most, heating18:30
wpwraksure. but the low-grade peroxide he used also dilutes it further. so he has a very watery solution there.18:30
wpwrakyou can stir with a wooden stick :)18:30
whitequarkbut I like when it happens on its own :p18:31
whitequarkand can afford it so *shrug*18:31
wpwrakthis one may be useful, too: http://www.piclist.com/techref/pcb/etch/CuCl2Calc.htm18:34
wpwrakyou still have to be present to check when it's done. so you may as well stir a little while waiting ...18:37
wpwrakalso, if you have a decent mixture, the process is fast. someone who has to sit and wait for an hour is clearly doing something terribly wrong.18:38
wpwrake.g., with a sufficiently aggressive mixture, i've had it etch a board clean in < 1 minute. note that, at such a rate, a) this is no longer an exact process, and b) heat becomes an issue18:40
wpwraknormally i prefer more leisurely speeds in the 10-15 minutes range18:42
wpwrakhere's another potential fun formula: http://www.stephenhobley.com/blog/2011/03/02/still-messing-with-forces-i-dont-understand-the-formula/18:45
whitequark(it's still etching... I started at 21:1818:47
whitequarkwpwrak: ooo vinegar18:53
whitequarkthat I'd be willing to work with18:53
wpwrakseems to be pretty slow, though18:53
whitequarkthe NaCl trick is very neat also18:54
whitequarkalthough it's weird a bit, considering CuCl2 is quite well soluble... 77g/100ml18:55
whitequarkwpwrak: http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html18:58
whitequarkthis one has a much better explanation18:59
whitequarkit's really neither HCl nor H2O2 that is etching the copper, it's Cu2+ oxidizing Cu1+18:59
whitequarkthen H2O2 restores Cu1+ to Cu2+18:59
whitequarker, oxidizes19:00
wpwrakas i understand it, there are two phases: 1) HCl+H2O2 do the etching, 2) Cu takes over19:00
whitequarkthat may be the case19:00
whitequarkso, the first result ever of "whitequark's process""22:24
whitequarkDocScrutinizer05 will be delighted to learn that the liquid tin coating not only doesn't stick to fingers, but also survives light scratching by tweezers22:25
whitequarkthe overall pcb quality is far below what I eventually want to have, though... there's poor adhesion of dry photoresist to the copper for some reason, flawed etching process and the printer apparently doesn't quite have enough resolution 22:26
whitequarkneither of the adjacent tqfp pads you can see should be joined22:27
DocScrutinizer05seen that, thought you had some obstacle in your exposure system22:28
whitequarkthe photomask has a thinner line where they've been joined, I guess it's 0.1mm instead of 0.2mm or somesuch22:28
whitequarkand exposure wasn't ideally perpendicular to the board22:28
whitequarkit's really a photomask defect, not so much as exposure or developing one22:29
whitequarklikely inkscape shat all over my photonegative when I used it to move the picture to the top of the page... its pdf import seems to be botched. it also ate a "finest" dimension rectangle I had22:30
whitequarkI think my negatives printed directly from .ps didn't have this kind of defect22:30
whitequarkDocScrutinizer05: my photoprocess is negative... obstacle would result in *missing* pads22:31
whitequarknot joined22:31
whitequarkanyhow. as I'm trying them the first time, I'm really delighted with performance of the mask and liquid tin22:35
whitequarkmask is quite easy to work with and has nice thickness, I'd say 1/2 to 2/3 of factory made mask22:35
whitequarkthey claim that the same mask is used in real fabs, I can believe that22:36
DocScrutinizer05it looks preety awesome22:45
DocScrutinizer05pretty even22:45
whitequarkit's completely even. the only difference with fab-made mask I can spot is lower thickness22:45
DocScrutinizer05how do you create solderstop mask?22:45
whitequarkit's dry film solder mask, so almost same process as resist22:46
DocScrutinizer05i was almost "don't cheat me, that's not a selfmade PCB!"22:46
whitequarkDocScrutinizer05: here's my "lab journal" with all details: https://gist.github.com/whitequark/6afc50083d55de0fce3222:46
whitequarkyes exactly, that is my goal :D22:47
DocScrutinizer05then I seen the joined pads22:47
whitequarkthe traces overall are mangled. but that is because of 3 hours of etching22:48
whitequarkit should get much better once I get the stirrer with hotplate22:48
DocScrutinizer05etching should probably be between 5min and 1h22:48
whitequarkthe etchant here should work at 40°C with constant stirring. t° of etchant was 23°C22:48
whitequarkfor some weird reason; the room t° was 27°C at the same time! it seems like etching consumes heat rather quickly22:49
DocScrutinizer05etching? hardly22:49
whitequarkwhat is your explanation for the temperature of etchant then?22:49
whitequarkit had three hours to get into equilibrium with my rather hot air (a/c heating on)22:50
DocScrutinizer05the starting temperature ;-)22:50
DocScrutinizer05maybe 18°22:50
whitequarkit was 26°C in the beginning and 23°C at the end22:50
whitequarknope, not so quickly22:50
DocScrutinizer05hardly imaginable that etching cools down22:51
whitequarkI believe etching itself causes this enthalpy change22:51
DocScrutinizer05though who knows22:51
whitequarkanyways. rule of thumb is: 10°C changes rate of reaction by 2-4x22:51
whitequarkso 20°C lower than recommended t° means it's 10x slower22:51
whitequarkat 40°C it would be 18min without stirring, and about 5 (a guess) with stirring22:52
DocScrutinizer05stirring is quite important to get equal etching results22:53
whitequarkI'm just too damn lazy to do it myself though22:53
DocScrutinizer05Lego ;-)22:53
whitequarkit would actually be cheaper to buy that $130 mechanical stirrer22:53
whitequarkconsidering how much markup is there on lego in .ru, and it wasn't cheap to begin with22:54
whitequarkit's not unheard for it to cost 10x...22:54
DocScrutinizer05you don't want a stirrer, you want that blood rockers22:54
whitequarksorry, what?22:54
whitequarkooo I see22:54
DocScrutinizer05ever seen blood donation? they rock the bags with blood22:55
whitequarkI do not, but I just googled it22:55
whitequarkI'm sure this thing http://www.youtube.com/watch?v=NeDgBuNoOAg#t=87 will work just fine22:56
DocScrutinizer05the magnet stick will ruin your PCB22:56
whitequarkoh, you mean mechanically scratch it22:56
whitequarkwhat if I make a "table" out of e.g. acrylic for pcb (or stir bar) to lie on?22:58
DocScrutinizer05I see......22:58
DocScrutinizer05before my inner eye....22:58
DocScrutinizer05a set of two plastic tubs22:59
DocScrutinizer05in one you milled a huge number of 1mm holes with your CNC22:59
DocScrutinizer05to the bottom22:59
DocScrutinizer05this sits on top of the other tub23:00
DocScrutinizer05in which your PCB sits23:00
whitequarkyeah, same idea, I think I'll just keep it all in one container and use a sheet of acrylic (with holes as you suggest) to separate23:01
whitequarkon tiny legs23:01
DocScrutinizer05and there's a tube from lower to upper tub that has foam in it, climbing up frpm the lower to the upper tub23:01
whitequarkI place the pcb under the table, I place the stirrer on top of the table, voila23:01
whitequark(if I place pcb on top, it's going to either close up all the holes, or, if I flip it, the etchant will be distributed only thorugh the holes => very uneven)23:02
DocScrutinizer05I don't think this will "mix" or move in any way the liquid under the table23:02
whitequarkit's easy to check. I just need to put a drop of dye under the table23:03
whitequarkor, actually I have another idea23:03
DocScrutinizer05yeah, and then you got that mega expensive mega useless magnet stirrer23:03
whitequarka set of "legs" for PCB 23:04
whitequarkso you drop pcb into etchant "face" down and the legs keep it above the stirrer23:04
DocScrutinizer05hmm, that *might* work23:04
whitequarkthe legs would be just a set of acrylic blocks with a slot milled in, where the pcb goes23:04
whitequarkshould snap on just with friction23:05
DocScrutinizer05I'd still prefer aquarium equipment23:05
DocScrutinizer05bubbles and tubes23:05
whitequarkoh, you want to have two tubs and a pump23:05
DocScrutinizer05yes, bubble pump23:06
whitequarkthere's some merit to bubbles for other etching process, namely CuCl223:06
whitequarkbecause oxygen restores the etchant to its virgin state23:06
DocScrutinizer05foam etching needs fe2cl-dunno shit23:07
DocScrutinizer05because the foam building properties23:07
whitequarkscrew fecl2, it's yucky23:07
whitequarkI want to touch it even less than wpwrak's devil mixture23:07
DocScrutinizer05I'd go innovative and use a drop of detergent in a persulfate etching liquid23:07
whitequarkfecl3 rather23:07
whitequarkto separate bubbles from pcb?23:08
DocScrutinizer05for the foam, when going foam etching23:08
DocScrutinizer05which evidently is best etching method23:08
whitequarkwait, foam etching?23:08
whitequarkhttp://www.hellotrade.com/cif-circuit-imprim-fran-ais/foam-etching-machine.html wth is this23:09
DocScrutinizer05or, even more simple: PCB face down, in a ~20° angle submerged in etching fluid23:09
DocScrutinizer05then at lowest end of PCB do the bubble dance like aquarium23:09
DocScrutinizer05makes for a foam etchin ^-123:10
whitequarkby the way: Polypropylene (PP) ...  it is rugged and unusually resistant to many chemical solvents, bases and acids.23:14
whitequarkI've just bought whatever was in supermarket, that was a lucky shot!23:15
whitequarkseems like my developing/etching containers will live a long time23:15
wpwrakHCl(35%)+H2O2(5%) is not even close to anything i'd consider satanic23:16
whitequarki guess you have not accidentally inhaled a bunch of HCl vapors23:17
wpwrak(your pcb) the solder mask is neat23:17
whitequarkyup, gives it a "professional" feel :p23:17
DocScrutinizer05http://de.wikibooks.org/wiki/Datei:Homebuild_Etching_Machine_2.png http://de.wikibooks.org/wiki/Datei:Homebuild_Etching_Machine_1.png23:17
wpwraki just use a wooden skewer to move the pcb while etching. works great. unit cost something like 10 US-cents ;-)23:24
wpwrakand one lasts for a year or two ...23:25
DocScrutinizer05meh, any slow spinning motorized toy or tool plus a 1m of cord will do23:26
DocScrutinizer05to rock the etching tub23:27
DocScrutinizer05like once per 2..4 seconds. when you can adjust the speed of the rocking movement, all the better23:28
whitequarkand what to heat it with?23:29
DocScrutinizer05well, I'd preheat the bath and use some isolating measures to avoid it cooling down too quickly23:30
wpwrakyou could use the mill. make a fire what burns below 660 C to heat the acid. use the mill's head to nudge the jar from time to time23:31
wpwrakif you do this .. don't forget to make a video and post it on youtube ;-)23:31
DocScrutinizer05or use blue or black tub and place it under a 500W light23:31
wpwrak(heat) or get a bunch of low-ohm through-hole resistors and make an array. they can go pretty hot before they degrade.23:32
DocScrutinizer05right! just mount one side of your tub to your CNC spindle (don't turn spindle), then move Z axis up and down all you like23:32
DocScrutinizer05yeah, resistors is what most DIY dudes use23:33
DocScrutinizer05I'd just place the tub on an electro heating plate, place the heating plate on a board, place the board on the CNC mill and lift it at one endor even place a rod as "axis" under the board and press down one side of board with the CNC mill23:35
DocScrutinizer05doesn't need a single screw or welding or cutting up stuff23:36
DocScrutinizer05probably all you need is to be found in your kitchen already, except the CNC mill23:36
wpwraki once made a "battery simulator" for GTA02: http://people.openmoko.org/werner/battsim.ps23:38
wpwrakthat one had a bunch of resistor arrays. got quite warm.23:38
whitequarkDocScrutinizer05: that one's almost as expensive as the stirrer23:39
DocScrutinizer05well, I bet you can find cheaper ones, it's been the first one I found23:39
whitequarkhttp://www.amazon.com/Aroma-AHP-303-Single-Plate-Black/dp/B0007QCRNU $16 :)23:40
whitequarkeugh, 110V appliances yet again. I damned hate americans and their nonstandard stuff23:40
DocScrutinizer05http://www.amazon.de/Unold-58815-Unold-electro-Warmhalteplatte/dp/B0012XP1OY/ref=pd_sim_sbs_k_2 30bucks23:40
wpwraki''d just fix the chemistry ;-)23:40
DocScrutinizer05a further 10 min and you're down to 15bucks23:40
whitequarkwpwrak: stirrer: $130, working lungs: priceless23:41
DocScrutinizer05ooh, you already are23:41
whitequarkactually, maybe I should just give up and have a 110V strip in my house23:42
wpwrakyou probably inhale more chloride when you open the tap ;-)23:42
whitequarkwpwrak: afaik moscow ozonates water instead of chlorinating. either way, it doesn't even stink of cl2, and people are pretty good at detecting it in tens of ppms23:42
whitequarkhttp://www.amazon.com/dp/B009P93TWI lol what23:43
whitequark"The Original MyWarmPet Heatpad - Microwave Pet Heating Pad "23:43
whitequarkooh, it's a heat accumulator. but the title made for quite horrible mental picture23:44
wpwrak... for when your cat gets tired of being dried in the microwave ... :)23:44
DocScrutinizer05or you go for the overkill solution: http://www.voelkner.de/products/38969/Sprueh-aetzanlage-1.html23:45
whitequarkno kill like overkill, indeed23:46
whitequark*cough* I went on local "amazon" to search for hotplate, I enter "hot" and it autosuggests "hotintimplanet" (all in russian)23:46
whitequarkas the only variant actually23:47
DocScrutinizer05or this one: http://www.voelkner.de/products/40127/Spezial-aetzmaschine-Typ-2030.html23:49
wpwrakjust buy a car wash and have it refitted ;-)23:53
whitequarkjust buy a pcb fab :p23:53
DocScrutinizer05honestly the next simplest thing to "stirr" after rocking the tub is to have some tilted plane below the etching liquid surface and a bubblestone from aquarium under the lowest point of that tilted plane23:57
DocScrutinizer05and you even could use your PCB for the tilted plane, face down23:58
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