Homebrew PCBs

Greetings.  Thought I'd throw in my 2 cents here.

If you apply a water soluble coating to the copper, you shouldn't need 
to modify your laser printer to be able to print directly on the copper 
(except perhaps to compensate for the thickness of the board).

We sell such at coating at www.laserpcb.com, and I thought I'd "open 
source" the recipe for everyone.

1 cup water
1 cup isopropyl alchohol
4 tablespoons Carbomer 940

We buy our Carbomer 940 here:
http://www.snowdriftfarm.com/emulsifiers.html

Blend REALLY well.  I use a hand-held immersion blender as found at:
http://www.target.com/KitchenAid-Immersion-Blender-Onyx-Black/dp/B00008GSA4

Instructions for applying the coating can be found at:
http://www.laserpcb.com/coating.php

Hope this helps.

Dave