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Author Topic: broken beads  (Read 1660 times)
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CarolB
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« on: November 18, 2012, 02:16:04 PM »

Hi All

I have only just started making beads but I thought I had made some lovely one's on Saturday.  I go and look at them today and some of them are broken down the middle.  I can't find or remember what I have read about this Sad So the beads were round and some of them I had made patterns with and covered in clear.  When finished I put them in heated balls in a slow cooker.

The mandrels were 3mm

thank you in advance Carol
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Josephine
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« Reply #1 on: November 18, 2012, 02:24:58 PM »

Sounds like a thermal crack. The bead loses heat more quickly where it is in contact with the mandrel. You may need to get them into the vermiculite a bit quicker or it might be an idea to use thinner mandrels until you have a kiln that you can put the beads straight into. The bigger the mandrel the bigger the heat loss it will cause.
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CarolB
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« Reply #2 on: November 18, 2012, 02:32:29 PM »

thank you for your reply I had a kiln bought for me for my birthday 21st October and I haven't turned it on yet Sad i'm a little scared by it... and I thought I would batch anneal has I don't have a lot of time in any one day to make a lot of beads - if that makes sense.

Carol
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Josephine
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« Reply #3 on: November 18, 2012, 02:53:45 PM »

Yes it does make sense but I think if you are batch annealing you would be sensible to use 2.4 or 1.6mm mandrels and make sure you don't let the bead cool too much.
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CarolB
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« Reply #4 on: November 18, 2012, 03:44:32 PM »

I need to use the 3mm to make the beads for the pens and wine stoppers I bought from tuffells for Xmas pressie's Smiley
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Pauline
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happy happy happy


« Reply #5 on: November 18, 2012, 04:30:12 PM »

what kiln have you got, if you need annealing schedule you can find them elsewhere on this forum, but it really isn't scary once you do it especially if it has a bead door.  most of the little kiln only use around 1 each firing so have a go
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Nicknack
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To bead, or not to bead? ..... stupid question!


« Reply #6 on: November 18, 2012, 04:55:40 PM »

What they said, plus you can use broken down the middle beads to make earrings or rings, so they aren't wasted.

Nick
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ARBeads
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« Reply #7 on: November 18, 2012, 05:10:59 PM »

Make them on the 2.4 and then gently ream out with a diamond burr. That's what I ended up doing, having made a lot of whoppers, without realising they weren't the normal 2.5 mm bar.
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Ruth & Andy


www.etsy.com/shop/arjewellery for beads!
Pat from Canvey
Only a little bit odd
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« Reply #8 on: November 19, 2012, 02:11:49 AM »

I thought I would batch anneal has I don't have a lot of time in any one day to make a lot of beads - if that makes sense.

I don't make a lot of beads in a day either, but set the "Hold" for say 4 hours....When finished making, wait an hour and then skip the kiln to the next program stage. On an SC2 kiln, it's middle button pressed once and left most button pressed twice. the kiln will then go on to finish the program with no more attention. Even DH has learned to skip the kiln for me if my lap is encumbered by an elderly cat or if I've gone out shopping.
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Blue Box Studio
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« Reply #9 on: November 19, 2012, 04:17:55 AM »

I set mine for 8 hours, do a couple of hours, wander off for a cup of coffee and then get back to a few more hours if I am lucky.  Mine's never cost me more than 1 to fire like this.  If I get a better offer of lunch then I just advance it when I am ready to finish for the day (up - start - start on my SC2) and then it's even cheaper to run.  The bubbles in a slow cooker were better than vermiculite but I still lost a lot that way.  Garaging in the kiln is the way to go with big mandrels and keeps my shedio toastie warm in winter!
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marklaird
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« Reply #10 on: November 19, 2012, 09:04:15 AM »

I'm like you, bought some beadables from Tuffnells for Xmas presses.

I've been using 3mm Mandrels and the fibre mat rather than beads and so far not had too many problems.

Made one bead about 2cm diameter in gravity pattern with clear vetrofond glass encase and it survived.

Helsbels very kindly does batch annealing for me as I've not got round to forking out for the kiln yet.

I make sure that the beads are evenly heated when I bring them out of the flame ( hot head on bulk for me) and then after about 15 seconds or so put them between the two sheets of fibre mat /blanket and don't open it again until done. About 6 inches of the Mandrels are also in the blanket so that may also help to help the heat loss down.

Anyway, just my tuppence worth.

Mark
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Dietmar
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« Reply #11 on: March 24, 2020, 04:40:58 AM »

I think this is more a thermal problem while melting the clear for the encasing. When finally there is enough molten clear the core bead might be too cold and get a thermal shock. Since you don't melt the bead down to the mandrel, again, the crack stays where it started. The bead is coling faster on the surface than inside. The stiff outer parts don't follow the still shrinking inside and there is the start of a crack te release the stress. Krxxx!

What helps?
Keep the core bead nice and warm, the whole time while melting the clear. Just let the surface cool a little bit before the big swoosh. Or go for a different method of encasing, swiping on in stripes instead the big-gather-and-swoosh methode.
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