Glass needs to be annealed, not so much the size of the beads I usually make, but if you are selling to the public, or making bigger beads it becomes a bit of a necessity.
If I made a bead and just left it out on the side it would crack in two as it rapidly cooled. You can cool it slower by a variety of methods, so that small beads do not crack... but this does not anneal the glass, it can still contain internal stresses that may fracture later on.
To anneal beads you need a kiln.
Kilns come in many shapes and sizes, mine is a small table top kiln and because I knew I also wanted to try my hand at glass fusing, I chose a kiln that can be used for both.
|Test firing - reject beads ready to be annealed|
Annealing strengthens the glass and makes it less prone to breaking, once glass has been annealed it can last for many years. You do this by using a kiln to basically "soak" the glass at the correct high temperature for the glass you're working with and then cool the glass VERY slowly in a controlled manner, so that so that the stresses and strains are removed, for this you need a programmable controller so you can set the speed at which the kiln heats and cools (ramp).
|Programmer built in to the bottom of the kiln|
Temperature wise when I'm annealing beads my kiln doesn't usually run hotter than 520oC, however when I'm fusing I typically take it up to temperatures of 805oC.
|Full door with integral bead door|
Due to wanting to fuse I chose a kiln that has a square interior space and more height, and mine has a "full door" as well as a "bead door" which is essentially a smaller slot door within the main door, so I can put beads in as I'm working.
What surprises people is how long this all takes, if I start a programme to anneal my beads, I won't see what I've made until the following day!
Would you be able to wait a day to see what you've made?