Homebrew PCBs

klmjr22(keithlmartin@...) is reported to have said:
> 
> > Just found that we had 2 Scrub Free cleaners under the sink.  Neither
> > has sulfamic acid listed on the label, Tilex and one called Scrub
> > Free.
> > 
> > Took a 6" x 18" copper clad blank that had some blemishes and tried
> > each of the scrub free cleaners in a 4x6" strip.  Both did show a
> > change in the color of the copper but neither took out the blemishes.
> > Washed off the board and dried it, then tried Tarn-X.  That fully
> > cleaned the board and no blemishes remain.
> > 
> > I think the Tarn-X cost around $5.  The label says to use rubber
> > gloves (the scum cleaners don't) so for my money, I will stick to the
> > Tarn-X.  There should be enough in the bottle to last me for many many
> > boards.  Maybe if I could find a Scum Cleaner that 'does' list
> > sulfamic acid on the label it would work better then those that don't,
> > but Tarn-X is working so I'm happy.  
> > 
> > I do wonder if the other 2 cleaners that Bill mentioned, Zap! and
> > Restore4, might be better but so far, I have not been able to find
> > them.
> > 
> > 
> > Thanks for the tip WB.  It might help those overseas that don't have a
> > source for Tarn-X or the others.
> > 
> > Wayne
> >
> I looked at the Household products database and found tarn-x is 3-5
> sulfamic acid but also contains Thiourea which may help cleaning.I
> found that Lime Away has < 11 percent sulfamic acid acording to the
> MSDS sheet. Tried some on some BAD copper and all the dark brown areas
> turned that nice reddish color you want. The black and green areas
> appeared to clean up with some scrubbing. This stuff is readily
> available. Assuming the sulfamic acid is what you want there is a
> product called Aqua Mix Sulfamic Acid Crystals available at Lowes that
> is a 99.5 percent pure sulfamic acid crystals. Don't know what it
> costs yet. But Lime Away does work and it doesn't have a lot of exta
> stuff in it you may not want.
> Keith

Way to go Keith!

Lime Away would seem to be something to try.  "Aqua Mix Sulfamic Acid
Crystals" would seem, to me, to be a bit of overkill.  I'd have to get
a rubber suit as well as boots & gloves.  :-)

I'll get some lile away tomorrow and give it a ahot.

Thanks again!

Wayne