From: Stuart Remphrey <stu@...>
I used the marker approach while a high school student in the 70's, with a Dalo(?) etch-resist pen and ferric chloride from Tandy or Dick Smith -- didn't realise I could have saved a bit.more on tye pen!Indeed, there are all sorts of clever ways to make PCBs. I've used both a resist pen, and a Sharpie pen. The resist pen worked better, as it was essentially a paint. The Sharpie ink tended to have pinholes, so worked better with wide traces and/or if you touched up the pinholes.
I've also drawn the circuit with a Dremel tool and cutting burr. It can be done freehand; but it was easier (fewer mistakes) when I clamped the Dremel to a little stand that held it at the right height, and then slid the PCB around on the table under it.
Another common approach is to use light-sensitive PCBs. I've used this method, and while it works, it's tricky to get all the details right. You need a UV light source, have to work out the right exposure time, and the right "development" time in the special development solution.
Then there is the "toner" method: Print your PCB layout on a laserprinter as a mirror-image. Place it against a clean bare copper PCB. Use an iron to heat and melt the toner, so it sticks to the PCB. Now dissolve off the paper by putting it in bleach overnight. That turns the paper to mush that you can gently remove from the PCB, leaving the toner as your "resist". I've used this method, but didn't like the results. It's hard to get the paper off without also removing some of the toner.
Another method is to use copper foil tape. This has worked for me for small boards, as the widest tape I could find was 2". Stick it on a piece of "fish paper" (phenolic-impregnated paper), and then print your circuit on it with a laser printer. The toner and fish paper are waterproof, and the fish paper withstands soldering heat. So it can be used directly as a flexible PCB; or epoxied to a sheet of blank PCB material for a normal rigid PCB.
I'm sure there are many more!
Excellence does not require perfection. -- Henry James
Lee A. Hart http://www.sunrise-ev.com