Ok have had quite a few hours torch time this weekend and have made about 20 beads ( doesn't sound alot but i do just make focals!) Out of the 20 all but 2 have cracked >:( :'( :'( I have been racking my brain as to the cause of this I know usually it's a case of them cooling too quickley/unevenly and yes I have had this happen with pressed beads but never with my long focals.
Now the only thing I can think of that I have done differently is I have watered down my bead release a few times recently trying to make it go abit further :-\ could this cause my beads to crack if the release is too watery??????? I am so flaming annoyed and tearful as I have wasted so much glass and shards it's heartbreaking.
Anyone any ideas??
Oh, that's such a shame..you must be gutted!
I'm not sure about bead release, but cuold you have accidentally used a different coe or an incompatible glass? Or a new glass for that matter?
Could you try to heal them?
Don't think it's the glass as I only use Effetre or CIM they are breaking as I take them off the mandrel which is making me think it's the bead release ???
Ooh, I'm not sure then ??? Bit of a puzzler that one. Sorry, I'm no help at all....I'm sure someone cleverer will be along to actually help soon.
Hope you sort it out!
xx
If you are losing so many, could it be your kiln? I check my schedule when i switch mine on, after the time the controller started skipping a step. Upsetting whatever it is!
The only problem I usually get with watered down release is the release crumbling away if you flame dry, never cracked beads. Maybe Mary is right you need to check your kiln.
I batch anneal so they are breaking before i even put them in the kiln :-\
Thanks for all your suggestions maybe it is just the fact they are cooling too quickly but why it's happened to so many this weekend is beyond me ??? ???
How annoying Claire. I batch anneal, too, and I've had the odd session where I've lost a few and not sure why. It could be you've thinned your bead release down a bit too much - I have done that myself and ended up redipping a few mandrels before today. Do you use vermiculite or fibre blanket? Personally I prefer vermiculite, but that is personal preference.
I water down my bead release a lot, but the worst it does is sometime break up whilst making a bead.. if you have a kiln right there, have you thought about annealing as you go? I always have, seems to be fine..
If you think it's because your release is too thin, you could double dip your mandrels?
We had a problem with bead release cracking at Diana East's class last week. She had new mandrels and cleaned them by heating them up in the kiln instead of using wire wool, which is what she believed was the cause of the problems we were having then. But it did lead to a discussion...she thought that there may be a problem with watering down bead release with tap water; Diana uses distilled water. I have had a nightmare today with mine cracking too, and I use tap water. I think that the humid hot weather also plays it's part, as today has been sticky, and the last time my bead release misbehaved the weather was similar. I also have problems if I overheat the bead release, particularly on hollows.
Maybe there's bead release pixies....
It could be the bead release.
I tried a different bead release once and had a lot of beads cracking along the mandrel and I know it was because of the release.
My only vague theory as to why this happens must be something to do with expansion / contraction of the mandrel and how much the layer of bead release insulates the mandrel from the heat and prevents this happening
???
As I said, very much a theory that the answer lies there somewhere, as I am no scientist.
I have also found CIM very heat-fussy anyway. Often found CIM just cracking even in the flame on me. I know everyone else loves the stuff, but I couldn't be doing with its fussy ways and sold my remaining stash off.
Is it possible you are using a new batch of one of your CIM colours that is maybe behaving a little differently to how it does usually? Or any other new colours added to the mix? I found CIM so incompatible, even with itself, that for me, any bead made with CIM was Russian Roulette.
Sorry to hear all the beads broke - that is heartbreaking. Hope you get to the bottom of it.
Emma
Hi
Were you encasing any of your CIM - I've found that some colours do not like to be encased!
BTW - if I add water to my bead release I always use boiled water.
Thanks for all your replies :) well I have dipped 5 more mandrels in the bead release I have got and I will have another go this afternoon. if it happens again I think it's time to invest in some new bead release before I waste even more glass lol
I have been having the same problem with my focals, they are all fine until I take them off the mandrels, I also batch anneal and they are fine when I take them off, but crack later, and they are the best ones that I have done - I'm gutted. How do you 'heal' them please?
Sue
If the bead release is too thin now, just leave the lid off for a whle until you like the new consistency. If your beads crack along the mandrel line at whatever stage, they are cooling too quickly. This type of crack is the result of thermal shock. Are you spending a little too much time working on the decoration of the focal and not keeping the core warm enough. Flashing the bead through the flame should be enough every few seconds to keep the whole warm then continue with the decoration. The beads may also be too large for the batch anneal process as the vermiculite or blanket allows the larger bead to cool too quickly. Larger beads need to be garaged. Even then, if you stop to admire the bead before popping in a kiln, it might still crack as it's cooled too much in the process.
In my case, the beads cracked down the middle only because that was the line of lease resistance I think. It was definitely the bead release that was causing the cracks somehow. (Believe me, I went definitive scientist on the whole thing for two days!)
I have found that often incompatibility can also masquerade as thermal cracking. Much depends on the shape / type of bead. But for me at least, incompatibility on heavily encased round beads will invariably crack along the mandrel (often only on one side of the bead though!). If I heavily encase moretti in bullseye or vice-versa, I will always get my cracks running along the mandrel.
With thinly encased beads or beads where the glass is all mixed up in different ways, the incompatibility shows in more traditional random crazing or J-shaped cracks running around the bead in the case of the thinly encased stuff.
I only say all that, because i think sometimes incompatibility issues are often wrongly dismissed as thermal issues and cracking along the mandrel isn't always definitely thermal.
I think the bead-release issue is thermal related though, in some shape or form, as to how much it insulates the mandrel maybe. All very odd.
It would be interested to test it out by double-dipping with the same release, or using it thicker and seeing if the cracking beads still occur?
Emma
Quote from: ejralph on August 11, 2009, 07:45:25 PM
I only say all that, because i think sometimes incompatibility issues are often wrongly dismissed as thermal issues and cracking along the mandrel isn't always definitely thermal.
I've heard this too - I had a problem with some Bullseye glass - a yellow that was encased with clear and shaped as a lentil. I've made loads that were fine and two made the same way cracked (all the glass was BE BTW) sometimes certain colours don't like to be encased!
Quote from: suzanneC on August 10, 2009, 08:27:56 PM
I have been having the same problem with my focals, they are all fine until I take them off the mandrels, I also batch anneal and they are fine when I take them off, but crack later, and they are the best ones that I have done - I'm gutted. How do you 'heal' them please?
Sue
You can heal them easier if you have them left on the mandrel. It is possible to ramp up a cracked bead in the kiln (on its mandrel). Get it up to 520 C and let it soak at that temperature for about an hour. Take it out of the kiln and introduce it gently to the top of the flame. You can then gradually get enough heat back into it to fuse it back together. You will lose surface decoration like bobbles or raised stringer as you'll have to melt them into the surface but it can be useful especially on larger beads that have taken a long time to make.
This is not an easy technique if you've already taken the bead off the mandrel and obviously doesn't really work out for those who are batch annealing.
In my experience I have had cracked beads when the bead release has been too thick but never too thin. Sounds like your beads are shocking before they hit the vermiculite or maybe there's a problem with the vermiculite. I once had a spate of cracking beads because the vermiculite was actually damp.
Thanks Redhotsal, I did begin to wonder about the vermiculite as they were quite big beads, I think I shall probably not try to batch anneal - especially focals and put them straight in the kiln (nearly typed bin then), it's just been one of those weeks.
Sue