PCBs from Scratch?

[segaloco]

So I had an idea today while reading about PCBs and I wonder if this would even be viable or if any folks here have tried something similar. I've got it in my head to get some sort of smooth substrate and non-bubbling adhesive and some foil and literally just glue together a conductive layer, then use a utility blade or Xacto knife or whatever to cut the mask out of the traces, then take the whole thing and clear-coat it. Yeah it's nowhere near the quality of a properly made PCB, but this idea is specifically to see how low tech I can manage to still make a PCB. This of course only addresses laying the mask, I haven't thought too hard yet about what dual-sided, thru-holes, or gold fingers would look like in this DIY of an attempt, but those would follow. Anyone done their own guerilla PCB making like this?

[Memblers]

I have not. But I have used an Xacto knife on a PCB, and I think it's difficult to be consistently accurate. For my case, just severing a connection occasionally, I switched using a Dremel instead, despite the extra setup and fiberglass dust hazards.

I guess the usual PCB is already copper foil and epoxy, so maybe a different adhesive could help?

Sounds fun if you want to hand craft something, how far this can go seems self-limiting though. If it's real simple, it's easy enough to use perfboard and wires. If it's real complex, it's going to need some machine precision. If you want the board to be 100% correct on the first attempt, you may want to prototype it anyways.

For through hole, looks like rivets are available. Multiple layers you would have to have everything lined up 100%. I suppose if it's drilled first, that's not so bad. Electrolytic gold plating uses cyanide, or mercury vapors with older methods, hopefully there's a better way for that, haha.

Years ago I used to see the photo etch supplies they had a Radio Shack, I was always tempted, but since I mostly just wanted to make NES boards anyways, it didn't seem usable for me. These days, one could simply use a CNC machine to cut everything, or some kind of 3d printed stuff probably.

[lidnariq]

My understanding is that the options for minimal latency are:
* PCB mill (fiberglass and copper dust hazard)
* Laser ablation (metal fume fever hazard)
* Photoresist, UV exposure, iron chloride, dissolve photoresist.

Photoresist can take a dozen boards spent on learning how to do the whole process. PCB mill has pretty dire pin spacing problems. Laser ablation is the only one that consistently produces nice results, but is also the biggest up-front cost.

[Pokun]

I have used the etching method where you draw traces with a marker pen and use sodiumpersulfate for the etching. It's supposedly the least messy method and it doesn't require an UV-lamp.
I've only made really simple stuff with transistor logic and LEDs and stuff mainly for learning the technique. It turned out much better than I hoped with a really nice solid board, and although it was a lot of work for even a small device, it's pretty fun and satisfying to make your own working digital machines without perfboards or breadboards. Plus you can draw any patterns you want, it's art!

I used a normal permanent marker pen as well as some kapton tape (heat-resistant tape) for masking the copper I wanted to keep. The kapton tape makes nice power and GND rails. Single-sided copper laminate sheets are easiest so you can solder on one side and have components on the other side, but you need to use jumpers for traces that needs to cross each others' paths (no vias). Unless you are using the UV method you need the non-UV copper laminate sheet.
A lot of planning ahead is needed, I drew the PCB on paper first and made sure there were no mistakes (which there were anyway of course). Remember that the solder side will be mirrored compared to the component side.

Sodiumpersulfate is bought in powder form and doesn't activate until you mix it with 30 to 40 °C warm water which is why it's nice to use. But use protective gloves and glasses and be careful. You have to rock it slowly back and forth until the copper is gone, and it takes quite a while. You also need a plier-thing that is resistant to the etching stuff so you can pick up the board when it's finished.
There are very fine PCB drill bits (I ordered cheap Chinese ones which worked like a charm) you can use to drill the holes for the components. I used a normal battery-driven drill and it works fine if you are careful, the bits can supposedly break if you don't hold it perpendicular to the board. You might also be able to use a pin-vice type of hand-drill if you find one that can take such bits.

There are various finishes you can use to protect the solder side once finished. I've seen UV-soldermask that needs a UV-lamp to cure and PCB varnish that doesn't. Some people use nail polish, though it's not very resistant to the elements.

The sodiumpersulfate become bluish when it has etched the copper and can be used several times. Once you are done with it you can't just discard it in the sink or in nature though. You need to keep it in a glass container (a jam jar works) and write a label that says it contains sodiumpersulfate and copper and then leave it at a waste disposal site that handles environmentally hazardous material.

[TmEE]

I used iron chrolide in past for the etching but also permanent marker and needle to scratch in fine details. I even made a 0.5mm TSOP adaptor board that way for my very own 4MB flashcart for MD long ago.

The worst part was drilling the holes, I don't want to do hundreds of holes if I really really must. Nowdays I let JLCPCB make all my boards and they've made thousands for me at this point.