Ordered the crapsman powder gun, but self isolation is VERY BORING. So I built one out of a pickle jar using a horror fright electric flyswatter as a high voltage source. Because I couldn't wait. A real hack job, but I did wash out the pickle jar even though it says it's "kosher", then I made it extra super kosher with some precious alcohol and acetone. Believe it or not this works & deposits a uniform layer on the PCB. Now I have to assemble the finest chinesium laser engraver and see what details are possible.
Components
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Pickle Jar, eat the pickles
Clausen pickles are good
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Harbor freight electric flyswatter
FREE with any purchase sometimes
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Laser toner
Sweep up by printer if you have a xerox
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Ballpoint pen
write a novel or discard the guts & use the tube
I tried another board with large fields, I see shrinkage afterwards along the direction of laser travel. Might need to color these in with sharpie in certain cases, or do the borders & use paint/tape etc. I don't see this as a big problem, as long as I'm not fixing little stuff I'm happy.
Burned one at 5% and 2200 mm/s and it's nearly perfect. But it's crooked & warped. Not going to bother wasting time on a pic. The software only accepts jpg, so I have to extract the image from the PDF. Then resize so it's right. The jpg is straight, but the print is way off.
So I'm trying Lightburn which imports PDFfiles, burning one now. The other possibility is the cable is getting hung up? We'll see. I can't get it to light the low power for testing size, but I used a big enough board to guess & it seems like it's going to work. I'd like to etch one of these eventually, since I have lots of acid just sitting here. FeCl
I would not consider attempting this with any other home method. But maybe above this too, some problems in the tight spots. But then I notice the one I printed:
oops. Maybe it would have worked if I made it full size. Fail of the hour...
This is the ramp to check my focus, to the right is on the table, to the left is raised 3/4". Bottom line is 40% laser, 6th from the bottom is 15%. I still see smoke @ 15%, but I'm going to try it on the rest of the board.
So I shot this at table height @ 15% laser.
This is most certainly usable, I'd etch it but it's a mistake design I don't need. There's no voids or any of those missing spots you get with the paper peeling method. Just a nice layer everywhere it was intended to be. No guessing with the iron. Plus I'm washing my hands quite a bit with the leaky pickle jar powder gun. As soon as the real one gets here (movement now) this thing is going back to killing flies.
Laser power @ 85%, probably too high. Could be scaling issues since I had to convert the pdf to a jpg for the software. close traces are touching, I'm thinking from heat transfer to surrounding powder. I very much like the consistent and void free layer of toner this applies though.
The PCB shown in the picture is unusable, with tracks touching each other, cut tracks and circuit prints with short circuits between the pins . I hope this is not representative of the method presented, otherwise there is still work to be done on this project!
A laser cutter will typically blow air down through the cutting head. The intent is to blow away any "cast off" from the cutting process so that it doesn't land and stick on the mirrors and lenses.
(Stuck bits of cast off will absorb the laser light and burn, ruining the optics. The optics have special metallic coatings, so when this happens the optics cannot really be cleaned.)
I've tried to sinter powder using a laser engraver, but ran into this problem. You can disable the air feed, but be careful about blow back into your optics.
I couldn't get this to work. Even with the air disabled the laser was too hot for the powdered plastic: it vaporized instead of melting. No amount of fiddling with the laser power would work, and the scanning motion of the head tended to blow the powder away in any event.
I'd be very interested to see if you can get this to work. There's lots of interesting hobbyist applications for this.
(P.S. - I'd also like to see details about the fly swatter powdercoat system.)
See latest project log, i may have it set too high but it seems to hold promise. My laser is pretty far from the work, so I haven't had the problem with the fan.
I see a lot of things in this project that make me want to see more. A fabricobbled powder coater from a pickle jar and an HF flyswatter? Can't wait to see more!
There's really not much to it. I have a tube going to the bottom of the jar, this is the inlet and serves to liquefy the powder and make a dusty cloud in the jar. I have a valve prior to adjust the airflow, I find tapping the jar is what gets the powder squirting nice. The outlet is just at the top of the jar, an elbow & ballpoint pen tube with wires soldered in an "x" over the metal tip - this charges the powder. The flyswatter is just 2 grids and counts on the fly touching both and he';s fried. I just connect one grid to the gun tip and the other to the work. The amazon box the cutter came in is my booth. Desperate times call for desperate measures.
It's just a quick and very dirty solution till the craftsman one arrives. I made sure I could re-assemble the swatter. I have another one packed away somewhere I used for a potato cannon igniter, if it turns out this thing is better than the craftsman.
The PCB shown in the picture is unusable, with tracks touching each other, cut tracks and circuit prints with short circuits between the pins . I hope this is not representative of the method presented, otherwise there is still work to be done on this project!