Kartáč velký PerfecTress™

Wow! Sounds like quite an adventure. I hope you didn't ruin your kiln floor! Make sure your kiln shelf is level. I also roll the betolts on a table to see where they naturally stop rolling than place them in the kiln that way and I always put a kiln post at the end of the shelf just in case they roll. If the betolts cracked, most likely they were heated or cooled too quickly. And yes, all molds need to be kiln washed. I also heat up new molds once before I use them. If you want to hang your betolts, I would suggest including a piece of wire in the bottle neck before you fire them. Either a high temp wire or copper. I have seen them done with a U shape wire inserted into the neck. Personally, I've never done the wire, but if I did I would use a bit of glue to secure the wire make sure the glue dries before firing. You'll need to brush the wire when it comes out of the kiln to clean it up. I wouldn't drill it. The betolts are pretty thick when they are done, and it would take some time and patience to drill through it successfully. Also, whenever I drill a hole into glass, I usually fire it again to smooth the edges of the hole and give it a more finished look.