PCB etch alternative?

[rmeyer8]

I was just thinking, considering that it can be costly, dangerous and just plain cumbersome to etch away the copper when making a PCB is it possible to simply iron a layout onto a plain sheet of copper, then take that cut copper layout and overlay it onto the board itself? Otherwise I'll stick with perfboard in the meantime

[R.G.]

Possible? Sure.

Easier, safer and cheaper than doing resist and etch? Wow. I don't think so. What follows is my personal opinion.

First, you need copper sheet to cut out. Presumably you're doing this with scissors or something. Copper foils on PCBs are 0.0014" thick. This is about 1/4 of the thickness of a normal sheet of letter sized paper. I don't know any place to get this stuff in small quantities. But you can get thicker copper sheet at crafts stores. It's quite expensive, compared to PCB stock.

Then it's expensive. You will cut most of the copper away. So your expensive sheet of copper foil becomes lots of little scraps and a few good pieces to glue down to the base stock.

Then it's time consuming. Unless you're doing only the simplest of patterns, you're going to be spending some hours with scissors.

Then it's difficult. Once you have your copper pieces, you have to glue them to the base stock with some kind of glue. Unless you use heat resistant glue, soldering will make the copper come loose again. And you have to get them in the right place, with an accuracy of about +/-0.010" if you put down ICs to get the legs in the right place. Then you get to drill the holes. That'll pull the copper loose unless you have a great glue holding the copper pieces down, too.

I've been making PCBs for over 40 years. It's different, but not difficult. You just need to know what you're going to do, and prepare for it. You're going to be doing chemical processes with stuff that's staining and toxic. This same could be said about laundry bleach. You'll need to do several steps. OK. No worse than setting up a computer, learning to log onto the internet. Probably simpler. You're going to have to be careful. No worse than crossing streets around city traffic.

[rmeyer8]

Yeah, you have some good points. If I were to do it, it would really be only a one time "proof of concept" type deal. I was just wondering if it was plausible.
By the way, thanks for re-popularizing/refining the uni-vibe circuit; my alltime favorite effect

[PRR]

They make pre-cut copper strip. It's called "WIRE". For many jobs, there's no reason it has to stick to the board. Just put your parts in holes (or even glue them upside down dead-bug style) and wire-up.

You can even transfer the "PCB" layout to insulating board to guide your wiring. In stompboxes, the width of the trace/wire is not critical. (It IS in micrometer radio work.) You may find "large areas" of copper on some PCB layouts; often this is just to conserve etchant, sometimes it adds just-in-case local shielding, often needlessly.

There used to be peel-n-stick copper tape, pads, DIP layouts for use on blank board. Also a high-silver solderable paint. I don't think they caught-on; if you find some it may be left-over from 1977 and past its shelf-life. There's a conducting paint for car de-icer traces. There's a tape for window burgler-alarm use, I dunno if it is solderable.

The killer advantage of PCB is that you wire it "once" and then you can make a million more bam-bam-bam without added errors. Like hand-copied books versus the printing press. How would we ever build TVs and PCs without "printed" circuits? In DIY that's kinda off the point.

Learn to make electrons go where they need to go to do the trick you want done. PCB, deadbug, terminal lugs(*), even just soldering part-legs together and hoping the contraption won't shake itself apart or kink and short.

(*) You'd think lug-strips would be "impossible" for any non-simple transistor box. Yet Shure built the M67 mixer and LeveLoc limiter on lug-strips. Very careful planning.

[edvard]

There used to be peel-n-stick copper tape, pads, DIP layouts for use on blank board. Also a high-silver solderable paint. I don't think they caught-on

I got some of this kind of stuff to play around with in '95 or so.
Yech.
The tape doesn't stick and the silver paint pen is messy and too wide to be really useful.
I dumped it out of the barrel and used a fine calligraphy pen, better for repairing traces than laying out a board.
Dead bug construction can make good use of wire wrapping point-to-point techniques, but it's a lot more work.
When I learned how to etch boards, I never looked back.

For the record, I called the local water treatment facility and asked about the toxicity of Ferric Chloride.
He said the Ferric part also comes from iron pipes and the Chloride part was like what they put in water to purify it, so no problems on his end.
I asked about the dissolved copper and he said that for a few boards here and there, I'm not putting much (if any) more copper in the system than what might leach out of the hot water pipes in my neighborhood.
Just FYI.

[Earthscum]

Quick reply before I go to bed... RS carries a conductive trace pen.

http://www.radioshack.com/product/index.jsp?productId=3964901


Also, my local electronics store (NTE distributor) carries 2 different pens... they just got them in the last 2 months. Hopefully the materials and technology caught up with the concept 

[Yazoo]

I have tried using a linocutter, the simple hand-held tool you can buy quite cheaply, on copper sheet pcbs and this works fine for larger layouts. I did once try to do an EA tremolo layout this way and quickly realised there was no way it was going to work for that.

[ahermida]

I own a PCB milling machine.  The machine comes with software that runs on a PC.  The software reads your layout in one of various formats: DXF, Gerber etc.  You need to tell it which tools are available and their size: drills, mills, routers etc.  Basically the machine mills out the copper that you don't want and leaves the traces.  It can also drill holes and cut the board in any shape you wish.  Its very cool for 1 or 2 sided boards.  I've save a lot of money and time making the board(s) as soon as I have the design.  The not so good news: $8000 for a basic machine with software and tools.  If you're just having fun its tough to justify the money...in my case I've been able to save thousands of dollars when creating designs that needed to be ready "yesterday".  The machine can also copy and paste the design and make a small batch of boards.  Is it a production machine? not really but it does save time and money.   

Alf

[rmeyer8]

Earthscum, was this fry's electronics? I know they carry NTE, I worked for them

[darron]

I own a PCB milling machine.  The machine comes with software that runs on a PC.  The software reads your layout in one of various formats: DXF, Gerber etc.  You need to tell it which tools are available and their size: drills, mills, routers etc.  Basically the machine mills out the copper that you don't want and leaves the traces.  It can also drill holes and cut the board in any shape you wish.  Its very cool for 1 or 2 sided boards.  I've save a lot of money and time making the board(s) as soon as I have the design.  The not so good news: $8000 for a basic machine with software and tools.  If you're just having fun its tough to justify the money...in my case I've been able to save thousands of dollars when creating designs that needed to be ready "yesterday".  The machine can also copy and paste the design and make a small batch of boards.  Is it a production machine? not really but it does save time and money.   

Alf

here we go....


i can top that with a $20,000 laser, and that's for a hobby! :S

it easily pays for itself, with self-satisfaction and one metric crapload less effort.