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]

Originally Posted by R4GlassStudio

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.