Patina Discolouring on Stained Glass Panels

by Sue
(Ireland)

When I wash my finished piece of stained glass, dry it, and apply the black patina and wash again, a month later, there appears a whitish stain, like the lead is leaking, when I rub this away or re-polish it, most of the stain goes away. How can I prevent this from happening?

Milly's reply: Hi Sue, thanks for your question. I've had the very same problem as you. I'm making the assumption that you're using copper foil? If you're using lead, you need to polish it as detailed on my site here:
Stained Glass Craft.
Back to the copper foil. You're right to wash after soldering, it neutralises the flux, but scrub it with household ammonia (for general purpose use) with one of those green pan scrubbers until it froths. Dry thoroughly with a paper towel.
Then get a wax cleaner - the type you can buy at car centres - and buff it until no more black comes off. At this point it should look entirely beautiful, and could be left here if you just want the silver. The waxing will get rid of the oxidation - that's what's causing the white stain to appear on your stained glass panels.
If you want copper or black patina, now's the time to apply it. Make sure you dry it off with a paper towel. If you're using black patina, rinse with warm water at this stage, and dry thoroughly, letting it set for a day.
Then repeat the waxing process, only this time leave the wax to dry before buffing up.
That should be it! Your passport to fantastically marvellous stained glass panels. I hope this does the trick.

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