Question about Metaling

Q: Have a Silver Stain question. I have a church piece done by Emil Frei, Jr, 1948. It appears to be Lambert's glass (gray/blue, purple). The Silver Stain has come off the original piece and the church wants it re-stained. There is metaling on the back; how do I remove the metaling?

A: It is very unusual for the silver stain to “come off”. The stain literally penetrates the glass and is as permanent as anything out there. I would be very curious to see some photos. Are you sure it’s stain and not enamel? Anyway to remove the metaling your only choice is a weak solution of hydrofluoric acid – use the proper safety precautions as it is dangerous stuff. I would be reluctant to refire the old glass, my suggestion would be to plate it with a layer of thin float glass – the silver stain takes very well on the tin side of float – you can refer to this illustration from my book: