A: I’m not sure I understand your question so I hope this answer helps you. The purpose of the adhesive on the copper foil is purely to hold it on the glass for the assembly process. It is not designed to hold your stained glass project together and when you run your soldering iron over the foil some of that adhesive comes out because of the heat. Once the foil is coved with the solder the adhesive is no longer relevant. The solder has now in essence created a lead channel and that is what is holding your window together; so, you wont have to replace the foil in a few years. Hope that helps.