homemade multilayer PCB?

Well, I don't know why we have to insult each other. It makes usenet a rather unpleasant place considering that it's already inundated with meaningless spam and dreadful trolls.

Anyway, I am just a hobbyist. I don't get paid to design circuits. I am not likely to spend $50 to have a board made for something that only I will play with. Especially knowing that the board might not work exactly like I want it to the first time. In other words, with regards to hobbies, I have more time than money.

Making a multilayer pcb seemed like a fairly do-able project. I just expected that others would have perfected a diy method by now. The only reason I would need a third layer is for something that looked better than a mess of jumper wires. I thought that maybe someone might have made a special conformal coating that doubled as a heat sensitive bonding agent or maybe a product that acted like a light layer of some flux like adhesive. Maybe I shouldn't have said laminate. It seems like it would be fairly easy to stack up to four layers by soldering pins to the middle layers before sandwiching them together. The boards wouldn't even necessarily need to touch.

I put more stock in experience than conjecture so I am intersted in hearing about what people have tried. I also realize that many things are easier said than done but the whole point of asking in the first place was to try to reduce the learning curve.

Thanks for all your input.

Wow. When the picture first started loading I thought it was a joke, but sure enough, there's a perf board under there.

My friend, go to a hobby store that specializes in stained glass. You will a selection of adhesive copper foils.

All in all, I think you should stick to 2 layer technologies. Develop skills to find ways to route everything in 2 layers.

Instead of building a monster PCB, find different chips that can help you reduce parts count or allow better routing.

Don't take address/data bus signal names as gospel, mix and match to ease layout.

Get familiar with a PCB package.

I've made many personal projects (back when I cared to do such things), and I always found a way to make planes and connect most signals with only 2 layers. Use resistors (1206 lets you route a trace between pads, through-hole 0 ohm resistors are great too).

Adding layers to a PCB requires pressing, heat and chemical processes to plate the barrel of the via. It's the only way I know how to connect reliably to inner layers that doesn't require a monk. It's just not easy to do.

The fact that you need to drill the via automatically implies that the inner layer copper is flush with the hole. It's always gonna be difficult.

And even if you could magically plate via barrels, you still need to laminate two boards together, with all the registration and adhesive issues that go with it.

Find a way to use on-line PCB shops like Alberta Printed Circuits and you can be prototyping the next day.

It's like programming, do you compile your own code or do you use some sort of software to do it for you?

On a sunny day (Tue, 27 Jan 2009 16:41:42 -0800 (PST)) it happened laylow wrote in :

If you look close you will see that the _power_ is routed by blank wires between the dips soldered on the board. Sorry for out of focus picture, old camera with no focus adjustment.

I have done about 10 or more boards that way for that Z80 project. Diagrams are here, click on the system14 link, then log in for the diagrams:

Z80 was fun, good old times.

I still have that system in the attic, but I think the EPROMS must be dead by now.... And I no longer have a monitor that can do 625 lines at 15625 Hz horizontal frequency. Any museum wants this? Maybe I should put it on ebay :-)

I made a "graphics adapter" rats-nest for a 6502 with a ram bank consisting, IIRC, of 16 2114 RAMS all piggybacked together.

There's several board houses out there that will give you a large enough discount on your first order that you'll get it for free.

Prototyped and iterated some multilayer printed transformer windings once, but only to determine the best structure, copper patterns and thicknesses for the professionally fabbed final product. I found that the copper surfaces needed a modest etching to bond within the kevlar used.

Have also done this using double-sided FR and a seperator for early iterations of 4-layer mixed signal/power assemblies, without actually bonding the layers.

The final product was always sourced from an experienced and UL-listed fab house, however.

I can't honestly say that this kind of work will get you anywhere, as managers seem to mistrust anything that doesn't miraculously appear out of a box, courtesy of a 'perfect' computer file entry, without any muss or fuss. The knowledge accumulated wasn't re-applied anywhere, that I'm aware of.

RL