WTF is going on with this glass???

Gardengirl · #1 2006-01-30, 7:51pm

I am at my wits end with this!! These beads are the EXACT same bead (except for size differences.) Even made from the same rods of glass, but this is my ratio for encased Bullseye beads. About 50/50. Half live, and half have these horrific cracks. It doesn't look like thermal cracks to me, I never got the bead cool enough to have that happen, and I put it in glowing red just like Bullseye likes it. It looks like incompatibility cracks to me, but how is that possible if I used the SAME GLASS????
I can't understand this. Maybe I'm perceiving it wrong - do thermal cracks look different in Bullseye than Effetre and I just don't know that?
If someone could help me out, I'd be so thrilled! This problem is what's keeping me from experimenting more with this glass - and I just love the colors!

Solana · #2 2006-01-30, 8:06pm

Hi Kristen! The only think I can think of is that you may have a cool spot in your kiln. I could be way off target, but if you're using the same amount of glass, and the same glass....I can't image it'd be a compatibility issue. I wish I had a better answer for you!

Melodie · #3 2006-01-30, 9:54pm

Wow, this makes two post on this issue.

Which clear are you using, BE or Schotts? What temp is your kiln at when you are putting them in and what temp are you annealing at?

I'll have to go try a few to see if I get the same thing. I have both clears so I'll check them both out. I don't usually make a lot of encased beads so I haven't ran across this problem.

Looks like gold purple base so I'll go give it a try. When I do experimental beads and simply leave them out to cool they look just like that.

Gardengirl · #4 2006-01-30, 10:41pm

I'm using BE glass.
I know I'm probably annealing it wrong or something. I put it into my kiln with my Effetre beads @950. I'm pretty sure that the annealing point is a bit higher for Bullseye.
I'd love to see what happens in your tests Melodie.

Hi Karla

So good to see ya around here! Super Yummy Tinyhead!!!

Kalera · #5 2006-01-30, 10:51pm

That looks like incompatibility cracking to me... what clear are you using? Is it always the longer beads that crack, or do the more doughnut-shaped ones crack as well? I encase the purple often, so it's got to be either the clear or the temperature, though honestly if the temp was too low you should get beads cracking right in half, not all over the place like that. I've had problems with certain Bullseye clears in the past, but it was because of accidentally mixing two of the types of clear, and they seem to have resolved it now. What other colors are in the bead?

Melodie · #6 2006-01-31, 12:39am

I'll let you know how my bead comes out, I made a pretty big one for me, but I really think it's your kiln temp causing you grief. I rarely use Moretti but when I do I only put Moretti in the kiln due to the lower temp.

BE has an annealing hold temp of 960. This is the average they recommend and has always worked fine for me. Actually, transparents annealing temp is slightly higher while opals are slightly lower but I have always stuck with the 960. I keep my kiln at 980 while I am opening and closing it to add beads and then cool down to the 960 to anneal. After that I anneal slowly (about 150) to at least 700. This is likely an overkill for beads but since I have a strong fusing background it's just second nature to me.

Again, I'll let you know in the morning how my bead comes out. I used #1401 Crystal Clear ... which of course is not crystal clear.

I don't usually use BE when I need a really pretty encasing.

Could also be that you got a bad batch of clear.

Melodie · #7 2006-01-31, 12:54am

I agree with Kalera that normally a bead that has been cooled too quickly usually breaks in half.

But ... this is one I gave up on the other night that was turning out sort of crappy and then when I overheated it I lost the ends. Didn't feel like trying to fix it so I either simply set it in my rod rest or put it in a fiber blanket, can't remember which. The cracks look similar to me.

FlameDancer · #8 2006-01-31, 6:09am

Kristen, are you putting it directly in the kiln or watching it cool off and then putting in there. I find that if I don't get it in the kiln, while there's still a pretty good glow, those beads come out cracked. I also have my kiln set at 960. You could try raising the temp a little bit.

R4GlassStudio · #9 2006-01-31, 6:21am

Go with a higher temp and a SUPER safe annealing cycle. My wife mixes COE all the time (96 coe reduction frit under three encasements of 104 COE clear and designs. After 4 years.... still no cracks. Try this annealing schedule, then lessen it..... as it is overkill.
Hold temp 980 for 30 minutes after your last bead is put in. 980 isn't a problem for BE..... it's not soft until around 1200. Cool 200 degrees per hour until it's 200 ( I know, 200 is low... 500 ending temp should be fine).
This schedule will let you "bend" the COE range a bit.

Melodie · #10 2006-01-31, 8:55am

Quote:

Originally Posted by Gardengirl

I'd love to see what happens in your tests Melodie.

Just took mine out of the kiln, no problems. I really think it is your kiln temp that is causing you so much grief.

The bead is about 15mm x 13 mm. My settings were:

Hold at 980 while inserting beads
Hold at 960 for 30 minutes to anneal
Ramp at 150 until 400 (again, probably an overkill)

I've actually never encased Gold Purple before, it's a lovely color encased ... Thanks!

Jude Rose · #11 2006-01-31, 11:01am

Quote:

Originally Posted by FlameDancer

Kristen, are you putting it directly in the kiln or watching it cool off and then putting in there. I find that if I don't get it in the kiln, while there's still a pretty good glow, those beads come out cracked. I also have my kiln set at 960. You could try raising the temp a little bit.

That's exactly what I was going to say.

Gardengirl · #12 2006-02-02, 11:01am

Thanks everyone. It's just so strange that I have no problems until I try to encase larger items - and this only started about 6 months ago (I don't use Bullseye that often - but I just ordered some fun stuff from Kalera

)
My annealing cycle is overkill, so I don't think it's that. Could be the garaging temp. I guess that I don' usually sit down with only one type of glass. That happens rarely. I usually use Effetre so if I decide to mess around with the Bulls then it gets put in the kiln with the Effetre cycle.

Kalera - I'm using BE clear (it's probably a really old batch too -place that I pick it up sometimes doesn't do a heck of a lot of lampworking business). It also seems that the donut ones are okay, but if I increase the size of the bead, it will crack. I thought a couple of times that I grabbed an Effetre clear by accident, but this time I know for sure - I left the label on the glass that says BULLS right on it, so I know it wasn't my mistake.

Oh and the beads are glowing really well when I put them in too!
BTW - OT, Jude - your monarch chrysallis in todays S& T is AMAZING!!! I'm really becoming a big fan of yours