Several years ago we fabricated ten painted windows for a wine cellar. Recently, there was a malfunction with the coolers and the humidifiers that cause excessive amounts of humidity in the cellar. As a result, the lead reacted with the condensation on the glass producing significant amounts of lead carbonate on the lead and even carried this deposit onto the glass. The windows are set in white oak frames that have been fumed with ammonia and then sealed. According to the wood craftsman, the ammonia should eliminate the possibility of tannic acid being formed when the wood is exposed to moisture. We have experienced and refurbished stained glass windows with lead carbonate "blooms" but nothing to this degree. Outside of re-leading these windows, are there any other solutions?
I would question this statement " ammonia should eliminate the possibility of tannic acid being formed when the wood is exposed to moisture". How long was the wood fumed? The longer the fuming the darker the wood gets. So the question here is did the fuming neutralize all the acid it the wood or not. If not maybe the wood DID outgas. Also, I'm guessing that the "bloom" on the glass is from your putty mix. Do you put plaster in the putty? Here is a link to cleaning the lead. But it involves the use of chemicals and soaking. Thus these methods may damage the glass http://nautarch.tamu.edu/CRL/conservationmanual/File14.htm