Help!!!

[Shelley]

I need some help... desperately!

All of my encased beads are cracking! I'm using Vetrofond clear, and have tried almost everything I can think of to fix the problem. I've cooled the kiln reaaaalll slow.... (didn't work), switching to Laucha clear .. (also didn't work).... omitting the silvered ivory I was using underneath...( no luck there)...
I don't know what else to do...! I'm using a computer controlled kiln, and beads are going in directly from the flame. I've lost around 2 dozen small tiger lentils due to this problem... they're all cracking just on the encasing layer.. no deeper. ..they all look fine when I take them out of the kiln, but an hour to a day later they crack....

Any suggestions??????

Shelley
Sydney, Australia.

[sailingzees]

If you are sure you are using a good annealing schedule as far as ramping up, soaking and ramping down the temp and nothing seems to work, I might look at my kiln if I were you. You may have some heating element problem, thermal coupler or even a bad controller. If all else being equal and you have not changed your beading technique or anything and you have already switched glass I would be highly suspect of the kiln.

[Shelley]

The kiln is brand new.... before I got this one, I was using a kiln with infinite switch so there was no ramping down, just switched off and cooled.. and I didn't have any problems with that, so it doesn't seem to make much sense when I can now control how quick/slow it cools. Funny how none of my ordinary beads with multiple layers crack, only the encased ones.....

Shelley

[*Sally*]

Hey Shelley,
What base colour are you using ?
There are several colours that just don't like to be encased. :(

Sally

[Shelley]

I'm making a base bead with black, and then layering a twistie with black & white with a tiny bit of silvered ivory. I've made these before without any trouble....

[*Sally*]

Bugger !!
I was almost sure you were going to say Coral. That glass is slowly becoming the bane of my existence. ](*,)

If your other beads are surviving with no problems it may not have anything to do with the kiln.

Back to basics :
If it's a straight crack down the length of the mandrel, usually a thermal issue.
If it's crazy cracking through the clear then it's more likely a compatibility problem.

You've tried different clears so maybe it's the black that's giving you grief ?
If all else fails you could try again but put a layer of clear down first. That seems to help with some cracking problems.

Hopefully someone else will jump in with more advice for you, nothing worse than broken beads. :(


Sally

[Shelley]

Yeah, its all surface cracking through the clear.... All of the glass is Vetrofond so compatibility shouldn't be an issue. I thought maybe I got a bad batch of clear.. but I didn't think of the black. I just got a new batch of each today so I'll try that next... It always has to happen when you have orders to fill!

[R4GlassStudio]

switch to moretti black.

[pennytoes]

Hi Shelley,

I know this thread is very old but you seemed to have the exact problem I'm faced with right now. It's cheesing me off something fierce! I recently bought a Bluebird Kiln and am very green when it comes to knowing very much about the programing. After I'm done working I garage @ 998 for an hour and then ramp down to 750. After that it cools to room temp.
I was encasing my tiger beads at first and getting the cracks and then I tried just dabbing the clear on first and then adding the transparent light amber on the clear, still cracking!
Hope I explained that well enough. Any suggestions would be very much appreciated.
Kelly

[jaci]

switch to moretti black.

ditto. I thought vetro black was a version of cobalt. cobalt does not like to be encased a lot of times. SIS is probably not helping this strain in the glass. ther than that i donno, great suggestions above.