I think the most used is a standard seal like when welding a blow tube to a larger piece of glass, or adding glass to glass. It is all the same, just different because of the color vescosities
It is all about what minerals where put in the glass. There are many
Any sandblaster will work to etch glass. The most common abrasive is aluminum oxide.
This is done at the beginning of the process, it is pre prep
A glass that sucks goes extinct. Terps sucks much like other colors you will not see.
When a customer offers to trade in a piece of glass, before we agree to anything have them submit photos of the pieces to assure we are even interested in the glass piece. Even if the piece has been used we still may accept it for a trade in.
There are many techniques. Most use colors already made and mix them, some add minerals to the glass to change them.
It is tricky to do if it is a formed shape. The trick is to melt the frit and the surface of the form, not melting the inside of the form. It is fast.
Gold and silver melt at different temperatures, the working temperature of glass will burn off the fume, which is why most fume is incased