Anyone have any experience with the at-home method of PCB making?
Before I use any of the PCB fab services I want to make some of my own. I’ve done quite a bit of research and am torn between a few different methods.
with etching I’d want the safest method since I live in a small apartment. The other option is strapping an etching tool to my 3d printer and making a slapdash cnc router.
Since I already have the printer I’m leaning towards the second method. It seems to be the most economical, though I do anticipate having to spend hours fiddling with the hardware.
My primary aversion to etching is that I’m overwhelmed by the number of methods. I want to use vinegar and hydrogen peroxide but assume that, since this method takes the longest you’d want the most durable transfer method which seems to be presensitized PCB. This is magnitudes more expensive than regular Copper Clad Laminate. Meanwhile I’ve seen people say they’ve used sharpie and have never had a problem.
Just making educated guesses, anyone’s experience in the matter is invited!
I make all my pcbs at home using bungart base material. Some years ago I bought a bag of uv leds and build a uv exposing unit. Its just an array of 100 leds with a simple timer circuit in a wooden box. The pcb lays on an acryl glas.
I am using Kicad to create the design. Normally I use only one sided pcbs, but my setup is good enough for 2 sided ones. I print my design on transparent paper and expose for about 90s. The time depends on the power of the leds and the base material, I did a test row to get the correct time.
The exposed pcb goes in a bath of natrium hydroxide and then in warm ferro 3 chloridbto etch it. The last step takes about 10 minutes.
My process is able to create 0.2mm traces without any problem.
I published some of my pcbs in the build thread.
The time in the natrium hydroxide is about 2 min. Its easy to see when its finished, because the design will get visible as light purple traces. I wipe very light with a soft brush until I see no more changes.
The ferro 3 oxide needs to be warm, 40 degrees C or more, to etch it very fast and clear.
This is my pcb of the twin t drummer:
Normally I etch pcbs for smd, the small pads and traces are no problem.
If you dig deep enough in this forum, you’ll find very thorough walkthru with all the things that work, and also a lot that don’t work.
But I can’t remember who it was who posted that…
I must thank @Dud for leading me to this thread and for the link to my efforts.
I will expand my explanation here it being more appropriate. I tried the presensitized (Bungard) board, expensive and on fibreglass, in my trials the Developer worked the first time but failed on the second time as though it was exhausted even though I left it for 1/2 an hour. I tried the Caustic Soda developer method this a/. didn’t work at all or b/. stripped off all the etch resist. I am a newcomer to doing this and would be the first to admit that I could very easily have made some mistakes.
I tried the roll of plastic stuff next, watched a few vids and then realised that I’d used the same but slightly thicker stuff years ago to make some Intaglio prints from photographs.
It’s only sensitive to UV light and can be handled safely in daylight away from direct sunlight. Two pieces of sticky tape one above one below will remove the protective layers, both before and after developing. I used SRPB board (the fibreglass stuff quickly ruins HSS drills) if the Developer does not work it can be stripped off with Caustic Soda and used again.
The Developer is Washing Soda £1.00 from Tesco and is very gentle leaves an obvious trace and I can see the white areas change to copper areas as I watch. Once developed I put the board back in the UV exposure box for 3 minutes to harden the plastic even more.
I use Ferric Chloride £12 for one litre for etching and by using Photoshop to reduce the the actual etching area to a few lines this took 1 hour instead of 3, cold and no swirling.
The remaining plastic is stripped of using Caustic Soda £1.99 for 500 grams from the local hardware store.
And the result, this is my first board which I have now drilled and begun to populate as I write this.
There are some splodges on it they don’t go all the way through the copper but I’ve put some solder across them anyway.
I used a small travel Iron to melt the plastic onto the board, a kitchen thermometer is on the way to me from Amazon at £3.45 including shipping. I will be able to set the Iron to 60 to 80 degrees C using this and I hope not melt bits of the plastic.
can you repair traces that came off during development? I’ve done about 5 boards so far, getting a bit better with each one. the most recent one i made only has a few broken traces. anything i can mask it with that wont come off with FeCl?
