3. Sealing glass parts

3.1 Direct sealing

Glasses recommended for electronics generally weld well together simply by fusing the areas to be joined directly.

In this way, two glass elements can be sealed together by simultaneously bringing the soldering points of each element up to melting temperature, then pressing them against each other and holding them in their chosen relative positions. The molten volumes are combined by mutual dissolving, and on cooling, the weld bead regains the rigidity that ensures a solid bond between the two initial elements. The atmosphere in which the operation takes place should preferably be oxidizing, air being very suitable; a neutral argon or nitrogen atmosphere may be appropriate in a few special cases.

A number of precautions...