Homebrew PCBs

On Tue, 09 Jan 2007 17:48:33 +0100, DB Express <dbxprss@...> wrote:

> I am attempting my first toner transfer home board etch.  The transfer  
> went better than I had expected for a first try, but there are two voids  
> in some filled pad areas that I would like to touch up before going to  
> the etch tank.  I know Radio Shack has a resist marker available, but I  
> was curious if there are any other options that would save me the 10  
> mile round trip to the local RS?  I suppose I could strip the board and  
> try another fresh transfer, but the rest of it looks very good, if these  
> two spots could be touched up.  Is touch-up a viable option, or a bad  
> idea?
> Nels


Generally it's a bad idea since it's lotsa work and not much holds up well  
as etch resist. But if the faults are minimal it is an option.

You can try any type of laquer (i expect nail polish would work too). If  
the areas are large enough you could stick pieces of tape over them.

Many permanent markers will not hold up all that well, laquer generally  
gives better results.

You can also use solder flux (resin type, "colophony" solved in solvent).  
Works great as resist as long as it's not thinned too much, and will aid  
in soldering. I always have a glass of it around for soldering. You can  
also coat PCBs with this for protection after etching, but i am lazy so i  
use a spray can of the stuff.

ST