encasing cracking

[mindy23]

Hi,
I've been working on some beads this last week that are a base of opaque blue, turquoise moretti or cim celadon encased with clear vetrofond, Lauscha or Reichenbach. 90% of the beads are cracking when they come out the kiln. I'm putting them in straight from the torch and last night I annealed them all in my Lauscha programme that has a really slow ramp down. SOme aren't cracking but there doesn't seem to be any pattern that I can see to iy. Does anybody have any ideas what I'm doing wrong?

[Carolyn M]

I have no luck encasing with Lauscha, and some of my encased CIM colours have cracked before. I've never used Reich to encase as I don't have any 104. If I were you, I'd carefully seperate my clear encasing glass, and do an experimental bead with each one, that way you may see a pattern.

Or you could encase with R4, I use this on 'temperamental' colours like silver glass, and have never had a crack

[mindy23]

I should re phrase that question. Can CIM celadon be encased with any of the 3 clears I mentioned? Can the moretti blue and turq be encased with any of these clears. What annealing schedule should work for these glasses? All other encasings I've done are coming out OK. I've wasted so much time and effort on these I'm really fed up...

[mindy23]

Thanks Caroline, I had posted my second question before seeing your answer.I know for sure that the celadon base has cracked with all 3 clears but unusually the ones I've cooled in the blanket are still OK as they haven't been annealed yet, how weird is this???? I've taken the reichenbach out of the equation now as it seems to crack with any of the colours so it's really just the Vetrofond and Lauscha. The ones last night were manly vetrofond which is weird cause I've never had any problems with that at all even over silver etc. I have been labelling my glass but I've been doing so many experiments I've got a bit muddled about which is which bead.

[gubnavnania]

Someone told me before that some opaque/pastel colors doesn't like to be next to mandrel, it will cracked. And it's better to use transparent color first (thinly layer) next to mandrel then cover with opaque/pastel.

[Peach Blossom Beads]

CIM has different annealing schedules for all of their colors. There are a couple of threads on here about it and a chart. I'm sorry I can't find it right now but take a look - do a search. The celadon doesn't like encasing, I don't think. But even if it did, your temp may be too low for it. If you're using CIM at all, you NEED the chart or you'll continue to have major issues. Sorry you're so fed up!

[Jody Lee]

Celadon from CIM anneals at a much higher temperature than Moretti - 1030 F. That might be part of the problem.

[mindy23]

I had been told that only peacock green, halong bay and cirrus needed different annealing schedules and that all theothers were fine in with moretti. Is that wrong??

[Jude Rose]

There are even some Moretti colors that don't play nice when they are directly against the mandrel. Go ahead and do some tests with your CIM glass. First put the thinnest layer of clear or some other transparent as your foot against the mandrel. Build the CIM color next, then the casing. I have amazing success with this technique even when using alabaster glasses that always crack when cased.

Good luck.

[mindy23]

thanks, i'll try that out. I will have to check my annealing schedules and make sure they are all working OK> Does everybody garage when working and then raise to anneal for 1 hour and then ramp down? I'm annealing at 520, is that too low?

[Peach Blossom Beads]

520???? What? Fahrenheit or Celsius? Please tell me you mean Celsius.

And Jude Rose's advice should work - it's an excellent tip.

[mindy23]

yeah, sorry I should have mentioned I'm in the UK so we are still on the other temp system.

[Carolyn M]

520 Celsius would be the temp I garage and anneal at.

Honestly, if you really want to encase the CIM, I'd follow Jude Rose' advice (actually, I'd probably give up and try a similar colour!)