Tarnishing???

[Aaron Taylor]

Hi all I had a Tarnishing problem and thought I would post it here for some advise. I have a glass piece that I have been working on in my free time and I pulled it out the other day to find out that it had tarnished pretty bad. It is a chipped piece that was chemically silvered with spray silver. It went on great and looked perfect when I applied the silver. After deposition I let it air dry and backed up with a mixture of asphaltum and fast size (rolcol). Could the rolcol fast size have impurities in it that caused the tarnishing? I all so coated it out with clear shelac after the asphaltum was dry. I was sure that it was very dry after silvering and before back up. The day that I silvered it, it was very humid here (I remember the concrete floor was sweating) Could that have been the cause?

I thought that you guys would have some good advise for me. Thanks for any answers.

-at

[Danny Baronian]

Hi Aaron,

the asphaltum and shellac is not the problem, the roloco probably is. I think someone had a similar problem with 1shop Fast Size, but not positive. I doubt you have any roloco old enough to contain lead, but that's most likely the source of contamination.

Asphaltum, mirror back up paint, clear lacquer or shellac would eliminate the problem.

[Kent Smith]

could also be sulphur in mineral spirits if used as reducer, brush cleaner etc.

too much tin also gives a dark, tanish like appearance.

[Aaron Taylor]

Thanks guys, I did use Turps for the reducer for the asphaltum/size mixture, turps is more pure than mineral spirits right? I also use the right amount of tin as called for and rinsed very well before silvering.

Would Permalic have sulfur in it? I do have some of that as well.

Thanks
-at