I wish it was cracking as in good... but it aint :-( I've lost so much work this week and I dont know whats going on?!!!!!!!!!!!! :'( :(
any ideas?
All this week I've been suffering from cracked beads, even though I have been doing what I've always been doing :-( I've lost 3 very good tree beads which happened to be the best that I've ever done as well! I didnt do them any different to how I usually do them - but each one has now cracked.
Is it me? the glass? or the kiln?
I have an sc2 with bead door and window. I garage, at 520c and it usually goes a little over by 5c now and again - and the tree beads end up getting around 1-2hrs soak as i make other stuff after... I'm using the same schedule as I've always used.
I just cant afford this amount of bead to crack like this :-( its wasting me time and money :'( I've barely got anything to sell now and have run out of money to live off of!!!!!!!
(posted similar to kiln section)
Well.....I'm no use at all but damn and double damn and a great big grrrr...............has that scared it into submission?
These are my 2 latest casualties...
I've put a ring around where they've crack to show where it is, as it wasnt showing up woo well in the photo.
The old lady bead had a crack going through the side of her face and through her eye - ouch!
Are you using a different glass? CiM or something?
The tree beads are exactly the same as usual - as I've been doing for weeks :-s no CIM...
All Effetre, except for a teeny teeny tiny tiny bit of ask104 used in the grass.
The old lady was lauscha caramello with effetre detailling.
well old people are like that
how long after coming out are they cracking?.. if they crack in the kiln i believe it may be that they are just getting that little too cool before going in.. apparently it does not have to be much, literally just working in a cooler room than normal?..
???
Aw Claire, they are so beautiful too :(
The cracks seem to appear after they have come out of the kiln, like even 2-3 days after! before that they were fine...
But all they have been doing has been sitting here!
well...they are cracking beads ;) :P
2 or 3 days later, doesn't really sound like thermal. They are usually bigger cracks too, right across, with me anyway. But I don't see how they could be compatability either, if it's the same glass you've been using? I tend to suspect compatibility when it's Lauscha, but other than that I'm no help! Such nice beads too.
They start of small - and then grow and grow...
I am wondering if they arent being annealled properly and maybe the kiln is playing up - and the stress within them starts to show later maybe?
Worth checking the kiln, even if only to rule that out.
Its at time like this I am glad I live in Stoke!!!!!!!! tee hee!
Though the thing should be within warrantee anyway... JUST
Well you have to have a crack at it Claire!
Oh Har Har Tan.... ;)
I am going to change my annealing schedule to the one that Izzy posted on the other thread and see if it helps me, its slightly different to what I was using. Seeing as I have a habit of making huge beads, it may help.
wish me luck!
Hope it works out for you Claire :)
It has suddenley got a bit colder weather wise the last few days. Maybe the beads are getting just that bit cooler than usual before going in the kiln?
actually you know.... i did change *something* on my annealing schedule in the batch that cracked - and that was the hold for garaging, which was set at just over 12hrs (I knew i was in for a long session!). Maybe it didnt like that being in the program and had a hissy fit at me!
(by the way any beads I am selling at the moment, are crack free and fully annealled as they were made a while ago!)
Quote from: Failariel on May 31, 2007, 11:34:15 AM
It has suddenley got a bit colder weather wise the last few days. Maybe the beads are getting just that bit cooler than usual before going in the kiln?
It could be that yeh, I guess - I am usually the opposite though - have too much of a habit of putting them in still glowing and they get fibre blanket bits on them! Oooops! When I work today I'll be very careful to make sure they havent cooled too much and twist them in the kiln and not place them down until the glows gone.
Good luck hun ;)
goodest of luck ;D
Claire,
Found this thread whilst taking a break from the packing of my beads. I wish to mention that where you must be careful during cooling is the annealing region. This is the part which goes from the annealing point down to the strain point (380°C) - this is usually where stress can be trapped during cooling through this zone, so you have to go slowly. Perhaps as a guide, using a 1/2"/10cm in diameter bead as a thumbrule (for larger beads, I do a longer slow cool):
Annealing dwell: 30min
Slow Cool: 5.38°C/min
Annealing point to Strain Point: 23.8min
Equilibrium dwell: 15 min
Final cool: 16.1min
Straining point to Room Temp: 33.7min
Of course the kiln will taking longer than those few mins to reach room temperature, though again I would like to stress here that you need to watch the ramping down from AP to SP (ie the Slow Cool or ramping down bit). After strain point has been reached and you let dwell for 15min, thereafter the stress is out of the bead and you can actually switch off the kiln totally if you like or have a firebrick kiln.
I personally don't shut off the kiln, since it's digital-controlled, I let the kiln run its full program. I also have used a e-control devise which measures how much electricity I used for the kiln and discovered that when the annealing program begins and somewhere along the way, the electricity is no longer drawn. The only thing I can't confirm is exactly when this happens as I didn't stand there to observe - what I mean here is you don't need to shut off the kiln if you have programmed it to run down to room temp, you are not drawing anymore electricity and not spending extra. With the program running its full course, you shouldn't need to worry too much about the beads cracking.
You have also observed yourself that you may have put in the beads too late and letting it cool too much where tension builds up on the bead. When I took my 1st workshop using the HH, I was told to put the bead into the vermiculite when it has lost its glow so that that the granules will not stick to the bead. When I finally got my kiln, I did exactly the same thing and most of the larger beads came out cracked as I put them in after the glowing has stopped. It's best to put the bead into the kiln while it's still glowing hot as long it is not in a soupy stage, that way you should eliminate your cracking problems.
Hope this helps.
Thanks Dora...
No cracked beads in the last few sessions!
I think the main culprit was the cold weather we had all of a sudden - and I was putting them in too late (my fear of the fibre blanket sticking was getting to me too much! LOL!).
I think that was my problem to be honest - Now its warmed up and I've been careful all is okay again....
I was working with a fairly slow cool down anyway and long anneal (at least 1 hr) but have increased the anneal to 90mins and made the ramp down to strain point even longer (70c per hour) and increased the dwell at the strain point. I do a switch off after strain point bit, and it normally takes about 60 mins to get from 371 to room temp (sometimes more).
Yay Claire, I'm chuffed it's back on track for you :-*