Is it possible to create a double layer PCB by gluing together two single layer PCBs?

Question

I'm really in a hurry with a university project. I need to finish the first prototype of an electronics board by the end of the week. It's a through hole board, no SMD.

Having just single sided copper boards and press-n-peel paper, I first tried to go by the single layer way. I can't get to the point of a decent routing. Even using jumper wires seems unpractical. I ended having more than 20 jumper wires connecting different parts of the board.

Then I tried the double layer routing. Everything fell into place in a matter of minutes. Everything looks clean and manageable. No jumper wires, no hard-to-fabricate vias in the middle of connectors, etc...

Could it be possible to develop the two sides of the two layers board onto different copper boards and the align and glue everything together?

It looks promising to me. The hardest part would be the alignment, but to me it looks quite easier that aligning the press-n-peel sheets. I could make alignment holes and then do the rest of the milling.

Has any of you tried this method?

What are the pros and the cons?

Thanks and sorry for my bad English

Answer 1

In my opinion it is always possible to have a single layer PCB with trough hole componentens, if the size does not matter. Sometimes you need a lot of wirebridges, but you can do that pretty neat, as in the pcb I made some years ago:

If you really want to go for a double sided PCB, what you say seems possible to me. If you drill some pads that are both on the top and bottom PCB before sticking them together, you might even be able to fix the two pcb's just by soldering the wires on the top and bottom pads. Onther option is to drill the mounting holes on both pcbs and use some nuts and bolts to hold them together while you solder. Afterwards you can drill all the holes for the component leads, so to match exactly.

If available you might want to use 0.8 or 1.0mm material instead of the standard 1.6mm so to prevent problems with e.g. DIP IC's that have pretty short legs.

Answer 2

PCB's are made out of fiberglass laminate sheets. Could try this, should work: Buy a small hobbyist's fiberglass repair kit. Very thin sheet of woven glass, for repairing small nicks and cuts in things like boats and motorcycles. Rough up both "top sides" of the PCB's with sandpaper. (The rougher, the better.) Mix up some epoxy, wet one top side, wet other top side, press and clamp together very tightly, making sure there are no air bubbles. It may warm slightly as it cures. In 12 hours it should be rock-solid. Trim off any excess with metal shears (don't grind it.)

I'd do this to bare boards, then do the layout, etching, and drilling after.

Answer 3

This can work. Make sure that you make the bottom board a mirror image of your design. That way you can glue the non-copper sides together, and have traces exposed on the outsides. You don't want traces between layers where you can't get to them.

The only major problem that I see is that the plated through holes (and vias) won't be connected through the board. You can solder a small piece of wire though the vias. And you'll need to solder your through-hole components on both the top and bottom sides. This is fairly easy with most components.

However, some parts cover up the holes. For example: most connectors, and some electrolytic capacitors. In this case, you can't solder the top side once the part is in position. Try to route all of your connections to these parts on the bottom side of the board.

Your English is great! Good luck.