Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Acetone (or any solvent) will leave behind at least a mono layer of oil or other organic material. This may be your problem as it can lead to poor adhesion of paint or other coatings to metal. Try cleaning the board with an abrasive cleanser such as Comet. You can follow this with acetone or alcohol if you wish. When properly clean, water should spread out over the surface rather than bead up. Let us know if this makes a difference.

Also, be sure you are applying enough pressure while ironing.

I don't know of any limit to the number of times you can try using the same board.

Craig