thermal cracks and annealing

[carolinainmymind]

The past few sets of pressed beads I've made, I have lost more than half to thermal cracks. I clean the beads, then batch anneal. Is the cleaning adding to the stress and making them crack? Will annealing before cleaning really allieviate that amount of thermal stress in a bead? (I think I need to press cooler in the first place.)

[Beatrix92]

I noticed I lost more pressed beads when I cleaned prior to annealing. I have lost far less since I have started annealing them first.
Bea

[carolinainmymind]

Thanks. And it seems like I lose more beads with transparent glass than opaque. I guess the transparent doesn't stand up as well to being pressed hot.

[one hot beader]

When batch annealing I found I needed to re-warm/flame polish the lentil beads very thoroughly, particularly along the mandrel line to stop them cracking in the vermiculite.

On the upside, a cracked bead made two perfect shapes to slump into cabachon pairs.

Now I don't get so many cracked beads, I miss my cabachons!

[28676bhe]

If you are pressing by hand, you might be going too thin. Remember that the mandrel is a heat sink and your bead will automatically get colder at that line. Reheat carefully but thoroughly, especially at the ends.