Bead release is very easy and cheap to make.
Most people use a mixture of aluminia hydrate and kaolin. I find that calcined aluminia can have less tendancy to form micro radial cracks when pre heated on the wires and prefer it to the hydrate. Pottery supply stores sell both alumina hydrate and kaolin.
If you use Aluminia hydrate then you can pack it into a clay pot and fire it to at least 1100 degrees centigrade to calcine it first. This drives off the water of hydration and changes its physical structure. The weight drops considerably. Allow to cool.
Take 500 grams of calcined aluminia and add 500 grams of powdered kaolin or I use a white high vitrification temperature. above stoneware, aluminous ball clay.
To this add 20 grams of powdered silica diatomite. Though not essential. Pass all materials through a 60 mesh potters sieve. Then add water stirring to a thick consistency. Pass this again through the 60 mesh sieve with the help of a rubber cooking spatula. Place into two jars. one for storage, and one for use. Add a high density bouncy ball. about 25 mm dia to the jar. When required shake the jar well " with energy" and the ball mixes the composition if settling has occured over a period of time.
Dip your wires and allow them to dry and re-dip them a second time to build up a decent coating thickness. Allow to dry and pre warm them before final burn out and use.
Some people add a little graphite to the mix to aid release. But the majority of this burns out in pre heating.
The hardness of the release depends on the vitrifiable components and the temperature that the release will be subjected to during bead making.
I have had no trouble with the release giving way during bead construction.
Occasionally I've blamed my release for cracked beads, but almost every time it has been due to elongated small bubbles in the beads producing sharp glass re-entrant angles and the bead has cracked from this point, or due to allowing the bead to cool unevenly while looking at it before putting it into the annealer.
This formula is used by many professional bead makers. Some add a little fireclay and others their own "sic" secret ingredients. ha ha.
I've used it for ten years and compared it to various commercial products but always can find no real reason to change away from using it.