Posted by Sarah King on January 24, 2004
Mike Jackson - TinAfter a long gilding session yesterday, I came to the conclusion that getting the right concentration of tin is absolutely vital to getting a great gild. I don't think that it matters how long the tin stays on the glass. You can pour it on and pour it off right away or let it sit - so long as you have exactly one ml of concentrated tinning solution in one fluid ounce of distilled water to begin with.
Silver, I think, will toleraate a wide range in tin concentration. If you are using stannous chloride crystals for gold, you must have one gram in one liter of water. The problem with crystals is that they absorb water in a high humidity situation and lose it when the air is dry. Therefore the weight - and size - of the crystals depends on the weather. Using a premixed concentrated tinning solution solves this problem because the crystals are already as saturated as they can be - so staturated that the solution does not "time-out" the way a diluted solution will.
RoderickHi Sarah,
I noticed the same thing the last time I tried Angel Gilding. After I used up the small batch of tin, I mixed up the next batch, but this time I just estimated the mixture. I didn't think the tin was that critical, but the next piece did not take the gold as readily.
I agree!
Mike Jackson
Danny BaronianI am on to the world of mirroring now.I received a nice kit from Sarah.Things went pretty good for the first time but I can't seem to get those nasty dark blothes from coming.Any suggestions.
Thanks for the help with the scratches and yes I got a load of glass the other day that were all pre scratched,no extra charge.
Roderick
The few times I've had problems was the result improper cleaning. Another cause could be from improperly mixed or contaminated chemicals.
Clean the glass with ammonia and whiting, rinse with water and wipe dry. Fingerprints or any kind of contaminate on the surface will show up in the end.
Are you using new glass? At one time I used recycled glass from double pain windows, which would occasionally cause problems.
Danny
Mike Jackson
D. Bernhardt - BINGO!Roderick,
I think the general cause of the dark areas is contamination. Cleaning is the cure...but you still have to watch for minute amounts of tin residue left from not rinsing well prior to silvering. Also, by just picking up the glass, you can introduce tin or other compounds through osmosis of the liquids on your hands. I hardly ever get a "perfect" gild or silvering job, especially if you are talking about full coverage mirrors, but when you consider the fact your "bright" lines will be very thin, most imperfections will not show up.
Mike Jackson
Mike Kingyuppers....absolutely must rinse glass clean after tinning. Not doing so gives the dark spots and every now and then a rainbow colour to boot.
Yes, cleanliness is next to, well, you know what. You shouldn't worry about knocking off the tin you just applied with too-harsh washing since it adheres chemically to the surface of the glass and requires a chemical stripper and scrubbing to remove. It's there to provide a one-molecule-thick metal surface for the mirroring metal to attach to.
Denver Chapter of the Letterheads