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Alternative Circuit Boards

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5/16/2000 5:05 AM

Alternative Circuit Boards

Hi!
Has anyone else ever tried this idea of making circuit boards?
I basicly just design and draw and burn a board and solder the components directly to the copper without making holes. It's a lot faster and easier then designing a normal circuit board with holes. Ive made hundreds of projects this way.
Here is a link to a page I made which will decribe it better.
http://europa.spaceports.com/~fishbake/acb.html.

John Fisher

5/16/2000 1:23 PM

John:

It looks like you've invented the precursor to surface mount technology in use today. For small projects, bench test equipment, or prototyping it seems ideal. However I wouldn't rely on it for mounting large or heavy components where the board would be subjected to mechanical shock, twisting, etc. The thin foil traces are not strong, and can be easily torn or pryed from the board. That's the main reason for thru-the-board holes to securely mount components. For instance, I wouldn't expect it to hold up in a tube combo amp, but it holds up well in solid state stompbox circuits.

Thanks for posting the pictures. They are clear and make it easy to see your method.

Doc

5/16/2000 1:53 PM

One very helpful use for this approach is with on-board electronics in guitars. I once had a pre-amp I made in this manner, using double-sided copper clad board for the control cavity cover plate. The circuit was etched on the inside of the cover plate and solder dirctly to it. The outside copper layer served as shielding. Mounting the pre-amp on the cover plate kept it well away from the pots on the inside.

If there is a downside to this, it is that things can get a might cramped if you don't lay it out in a planful way. With holes, you can clip away any leads that obscure your ability to solder in components. With a one-side approach, you need to be able to solder leads in the midst of components.

5/16/2000 10:31 PM

Hey John,

This was described in an old British ham radio manual, as 'dead bug construction'. So called because the ICs looked like squashed bugs once you splayed all the leads out to get them touching the copper. It works a treat and I use it wherever the voltage or current is too high for stripboard.

To make things even quicker, you can just draw on your board design with felt-tip pen and then zip along the lines using a Dremel and a small burr to take the copper off. Saves monkeying around with etching chemicals

5/17/2000 2:26 PM
R.G.	Alternative Prototyping Techniques You might want to look at the article on effects prototyping techniques at GEO for a roundup of prototyping techniques. I have used the technique you show. Works well as long as there isn't too much mechanical stress on the parts. For small resistors, caps, transistors, etc., it works fine.

5/18/2000 6:05 PM

Re: Alternative Circuit Boards

Q{Has anyone else ever tried this idea of making circuit boards?}

Ever looked inside a Mesa Boogie?
I have used this technique in making custom channel switching preamps with cf buffered effects loops which I installed in various Fenders, mostly Bassman Amps. Most of these were done in the 80's although I recently had a customer force me to convert his Bassman head into one of these custom jobs. I tried to talk him out of it - honest!
RE

5/19/2000 5:54 AM

John:

Looks like a great way to build prototypes! For some of the parts you *could* drill holes to secure them better, but mount them on the copper side as you suggest...

Do you use a regular Sharpie to draw out your patterns? (They have a special etch resist pen but it costs much more than a Sharpie and it sure looks the same to me!)

--Thanks!

Steve Ahola

P.S. I would be nervous about power tube sockets since those suckers will generate a lot of heat... Enough to melt solder? Maybe not but I'm not sure that I would like to take that chance. (Most people will mount the tube sockets directly on the chassis anyway so that should not be an issue.)

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