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

Thank you for your comments.

Well, Harvey, covering the pads would be an issue for a SMT board, yes.   That is what made me think of using nail polish---it already has a very small brush so you can overcoat the artwork while avoiding the pads.   I don't think artwork would ever overlap a pad.

Now I don't know how durable nail polish is compared to Krylon.   I simply thought you might be able to apply it to the top side of a THT board without having to mask the board with masking tape.

I suppose I ought test these coatings to see which coating is more durable for this application.   Maybe apply toner to a bare rectangular board divided into four quadrants by a vertical bisecting line and a horizontal bisecting line.     4 identical quadrants laminated with lettering denser than on the average board.    I could coat quadrant I with cheap clear nail polish, quadrant II with expensive clear nail polish, quadrant III with Krylon, .....what about quadrant IV ?

I'd need to invent some kind of  flagrum for beating the board surface equally  in all four quadrants in order to scratch it.     Just to see which of the coatings is most resistant to scratching that might occur (while populating the board).       I suppose I could use some kind of pegboard with through-hole resistor leads epoxied into the holes and sticking out a few mm.

This 4-quadrant test might also reveal if any of the coatings change
the reflectivity of the board--for example, making it glossy where you
apply the coating and matte where you don't--making it look weird.

Am thinking scratching the board surface is most likely when:
∗ inserting metal screws into the four holes in the board's corners
∗ inserting the leads of TH components when populating the board.
∗ accidentally dropping something onto the board

Am I missing something important?