No, there are special alloys and techniques for directly bonding metal to glass. In a lot of cases the approach is to keep the bonded area close together to min

No, there are special alloys and techniques for directly bonding metal to glass. In a lot of cases the approach is to keep the bonded area close together to minimize the distortion of the metal from the different expansion rates. Materials like Kovar are designed such that it very closely matches the expansion curve of glass so that it forms a hermetic seal without any kind of sealant between the glass and the metal. https://en.wikipedia.org/wiki/Kovar https://en.wikipedia.org/wiki/Kovar