Okay... this has me baffled...

[Cosmo]

I've recently been working with a lot of soft glass. I've been preparing for an encased floral class I'm teaching. I'm using Lauscha clear for the encasing (which I have been using for two years with no problem) and I'm getting cracks in all my pieces. Not coming out of the kiln - they look fine after they come out and I take them off the mandrels. These cracks are developing days later. They are all cracks running from hole to hole. I haven't cleaned the bead release out of them, so I know I'm not cracking them while doing that.

I had made many beads like this a while back, and I still have many of them. Some are over a year old, and they are still fine. Also, this clear is from the same batch I was using then. I bought 5 pounds at one time, so I'm still using the same clear that is in the old beads that are fine. I am using different bead release (Sludge Plus now, old beads were using Foster Fire) but I wouldn't think that would make a difference.

All the colors are standard Moretti colors (except one which was that Messy pink). No colors that are known to cause cracks. No frit or anything either.

I'm annealing them at 960 just like the old ones. In the same kiln, using the same program on the kiln. I was taught early on to put Lauscha clear into the kiln a little hotter than you would with other 104 COE glass, so I have been doing that all along.

But, for some reason, everything I've made in the past couple weeks develops cracks a few days after coming out of the kiln. Any ideas?

[Carolyn M]

I don't really have answers for you Cosmo, but could it be that there are different ways of working with boro and soft glass? I've never worked boro, but have heard it's more forgiving as far as thermal stress. Maybe you are not keeping your bead warm enough while encasing, or before putting it in the kiln.
In addition, I've found that Lauscha is not always that compatible with Effetre, I've switched to Vetro clear after horrible experiences with Kugler (anyone want free glass?), and have not had any problems with cracking.

[squid]

Hole to hole is a thermal crack. Sounds like you are not keep your bead warm enough.

[Cosmo]

I worked in soft glass for a year and a half before switching to boro, so I know a little about it. Like I said, it's weird that it's cracking days after coming out of the kiln. All of the old beads (some using the exact same colors) are still fine.

I've heard a lot of good things about the Vetrofond clear, but I was always of the "if you aren't having a problem, then don't switch" mindset about my Lauscha. Now I'm having problems, so maybe I should switch. I think I'm going to order some and try it anyways. Do they make Vetrofond in big 10-12 mm rods like the do Lauscha?

[Cosmo]

Originally Posted by squid

Hole to hole is a thermal crack. Sounds like you are not keep your bead warm enough.

Yeah, but cracking days after being annealed? Can they still thermal crack then?

[SuzyQ]

Yes they can still thermal crack after being annealed and days later. I have seen it with ocean green and lauscha, effetre violet under lauscha and red purple under lauscha. Yeah, it took me a few tries before I switched, lol.
You can get big fat rods of Vetrofond and I have them. 13mm.

[Cosmo]

Cool. Now I have to find somewhere I can get big Vetrofond rods...

[squid]

I have had them crack like that many days later also. If the bead is pretty enough and it cracked right in half, I will clean out the bead release and fuse it in my kiln - can make GORGEOUS cabachons.

[Wonker]

I think Flametree glass in Atlanta carries larger diameter Vetr. clear as well.

[kbinkster]

The initial crack can be very small or even in one of the opaque layers that was encased and can take a little while to get bigger and work its way to the surface.

[Cosmo]

Originally Posted by kimberly

Try Frantz. They have the larger diameter Vetrofond. That is what I use.

Yeah, but I don't have an account with Frantz. I have several wholesale accounts, but none of them carry Vetrofond.

I hate paying retail prices...

[sleekbeads]

COSMO... same thing happened to me last year. I ruined 10s and 20s of beads before I decided to call where I bought it from, turns out I got my hands on a bad batch. Dump it and get some new stuff.

(although to be honest, after that, I refuse to touch the stuff anymore)

good luck.

Jo

(ps... EXACTLY the same thing... days and days AFTER taking out of the torch)!!!

[Aleigh]

Using any silver, silver glass or dichroic? I find if I use any of these and encase with Lauscha clear I am about 100% on cracking. But only with the Lauscha clear.

Amy

[Debbie]

Gee, this thread is depressing. I would not have thought that properly annealed beads would crack so long after the fact. Now do I have to worry about every bead I've sold or given away that is encased in Lauscha clear? (which I love, btw).

[Jude Rose]

I had this happen to me too. It cost me so much money in time and materials. I had no problems with Lauscha before and then got a new batch and just couldn't believe it was the clear's fault. It was! Didn't like the Effetre special orange underneath.

Won't touch Lauscha clear with a 10 ft pole now. Sorry you had this happen, Cosmo.

[Anne Londez]

Originally Posted by Debbie

Gee, this thread is depressing. I would not have thought that properly annealed beads would crack so long after the fact.

Proper annealing doesn't cure thermal shock. If your bead has been shocked (let cool below annealing point and reheated briefly on the surface but not down to the core for example) and not reheated all the way through to the core to the *elastic* stage, the tension is there and annealing will not change anything. As to beads cracking long after, tension in glass works strangely. It can take a long time for the actual cracks to develop or at least to be visible.

[Cosmo]

Strange that my technique and skills have come a long way since then, but the older ones are fine, and my new ones aren't.

Oh well... I'm still trying to find a price break on some Vetrofond clear. I have to buy enough for my classes, and enough to keep in stock for our store as well. If anyone knows of a good supplier that carries it, please let me know. Anyone aside from Frantz, that is. I've already checked into that and you have to buy $10,000 a year from them to get wholesale pricing. I wish I was at that point. Not right now, though...

[ChrisM]

I've had the Lauscha incompatability cracks and they are not hole to hole, so I don't think changing glass will help. If you are making them properly and getting them into the kiln without thermal cracks, I wonder if your controller isn't reading the temps right.

Chris

[Karen Hardy]

I get compatability problems with Lauscha all the time.
I won't use it to encase Moretti or Vetrifond anymore.
I love the Vertrifond clear - very smooth and bubble free.

I think, if you have not had problems with the moretti/lauscha
combo in the past, you MAY be admiring your beads a bit too
long before kilning them. Even if you do get it really hot before
sticking it in the kiln (and I always kiln Lauscha while it's still glowing
red) it still may not be enought to make up for the thermal shock of
you drooling over your pretties.

[Anne Londez]

Originally Posted by Cosmo

Strange that my technique and skills have come a long way since then, but the older ones are fine, and my new ones aren't..

Assuming that it's a thermal shock problem, it might help to make sure that at no point when making your bead you let it cool down enough so that it takes more than 5 seconds for it to go back to glowing red when re-introduced in the flame. Working boro you might not need to pay it that much attention.
Have you encased with another soft clear ? I wonder if your problem would be similar with any other color or make or if it is just Lauscha. Maybe the Lauscha's partial incompatibility enhances the thermal shock problem, but maybe you let your base beads cool down too much before encasing. That could be part of the problem if you don't reheat the encased bead enough for the core to get molten again. Don't know if that helps, it's hard to tell without seeing how you work and I'm puzzled too

Edited to add that all my Lauscha incompatibility cracks didn't look like thermal shock at all so far, more like a web of
cracks at the interface between the clear and the offending color.

[SuzyQ]

Mine looked like thermal cracks. I use the same method with many other colors but certain ones would crack. It didn't always show up when I took them out but over time. I would notice one and set them aside, slowly they would all begin to crack.
I have had this sort of thing happen with frit and certain glass too.

[GinaJ]

I use the Vetro Crystal Clear (I encase EVERYTHING), and I get the fat rods from Jon at LB Supply. He may not have them listed on his site, but he will get them for you if you ask... and he usually has a great sale going on.

[MaryBeth]

You have suggested all of your things that might be variable have remained the same.

So - perhaps your thermocouple is failing. They only last for a couple of years and if you haven't replaced it recently it may be giving you a false temperature reading.

Lauscha is very sensitive to temperature changes. I never garage or soak Lauscha below 980 and 10 or 20 degrees higher that that isn't a bad idea either.

A new thermocouple should only run you about $15.00. Replace that before replacing all of your glass and see if that makes a difference.

[Emily]

Originally Posted by Jude Rose

Didn't like the Effetre special orange underneath.

So maybe it was the fault of the special orange. There are some Effetre specials I have a lot of trouble with, even when I do the core of clear with a thin layer of the special.

[Cosmo]

Originally Posted by Anne Londez

Assuming that it's a thermal shock problem, it might help to make sure that at no point when making your bead you let it cool down enough so that it takes more than 5 seconds for it to go back to glowing red when re-introduced in the flame. Working boro you might not need to pay it that much attention.
Have you encased with another soft clear ? I wonder if your problem would be similar with any other color or make or if it is just Lauscha. Maybe the Lauscha's partial incompatibility enhances the thermal shock problem, but maybe you let your base beads cool down too much before encasing. That could be part of the problem if you don't reheat the encased bead enough for the core to get molten again. Don't know if that helps, it's hard to tell without seeing how you work and I'm puzzled too

Edited to add that all my Lauscha incompatibility cracks didn't look like thermal shock at all so far, more like a web of
cracks at the interface between the clear and the offending color.

First of all, these are definitely not incompatibility cracks. They are single cracks that run from hole to hole. Believe me, working with boro I know what an incompatibility crack looks like.

Yes, I do let the beads cool down a lot while working. I have always done that. I do that so that the encasement doesn't disturb what it's encasing. However, I then heat them up to pretty hot when I'm shaping them. I do keep the piece pretty warm while working.

I'm wondering if it's just bad luck or something. I use the same kiln for fusing, so I know the temperature control is pretty accurate. I'm going to try some Vetrofond once I find it and hope that it will fix the problem.

[Gardengirl]

Originally Posted by kimberly

Try Frantz. They have the larger diameter Vetrofond. That is what I use.

Dittto:
I love big rods of clear, but my last batch of Lauscha clear made me crazy. It was a crap shoot - was it going to crack or not?
I never got hole to hole cracks, but spiderweb ones like incompatibilty. If you're putting the bead in even slightly hotter than normal, it couldn't be thermal I'm thinking.
There's been a lot of complaints floating around lately about cracking Lauscha clear.
I use Vetro clear and that's it.... the bigger diameters seem to have less problem with bubbling and scratching - but then again, I'm too lazy to peel the whole rod like I should.
I also get mine from Frantz.

I keep the Lauscha clear for use by itself as a sculptural, marble, or clear bead with small decoration on the top.

Best of luck, Cosmo

[MaryBeth]

Originally Posted by Emily

So maybe it was the fault of the special orange. There are some Effetre specials I have a lot of trouble with, even when I do the core of clear with a thin layer of the special.

When I took a Loren Stump paperweight class he warned up about using the special colors for any of our components. He said they almost always would cause cracking when encased.

[Cosmo]

Originally Posted by Gardengirl

Dittto:
I love big rods of clear, but my last batch of Lauscha clear made me crazy. It was a crap shoot - was it going to crack or not?
I never got hole to hole cracks, but spiderweb ones like incompatibilty. If you're putting the bead in even slightly hotter than normal, it couldn't be thermal I'm thinking.
There's been a lot of complaints floating around lately about cracking Lauscha clear.
I use Vetro clear and that's it.... the bigger diameters seem to have less problem with bubbling and scratching - but then again, I'm too lazy to peel the whole rod like I should.
I also get mine from Frantz.

I keep the Lauscha clear for use by itself as a sculptural, marble, or clear bead with small decoration on the top.

Best of luck, Cosmo

I can't use Frantz. I need somewhere I can get wholesale pricing because it's something I'm going to sell in our store. If I pay retail from Frantz, I can't sell it for retail. I have to mark it up. To get wholesale pricing from Frantz, you have to buy $10,000 per year from them, and I can't commit to that right now.

[Anne Londez]

Originally Posted by Cosmo

Yes, I do let the beads cool down a lot while working. I have always done that. I do that so that the encasement doesn't disturb what it's encasing. However, I then heat them up to pretty hot when I'm shaping them. I do keep the piece pretty warm while working.

Then I think it's what I was saying, that you let the bead cool too much and shock it. Try using the *Smircich* rule, which helps learn how long it takes for the glass to solidify without getting below shock point: when your bead is glowing orange after you've shaped the bead, it takes about 10 s (more if the mass of glass is bigger of course) for the glow to disappear, then another 10s for the glass to settle to the core. Count those 20 s and then bring the bead back in the top of the flame and reheat gently just so that it will glow slightly red on the surface when in the flame but will lose the glow instantly when taken out. That's the perfect temp for casing, the glass is hard but not too cold. It helps to count in the beginning but after a while you get a sense of timing for the glass. That's the main difference between working boro and soft glass for me, you have to be aware at all times what temp your glass is at exactly.

[PolychromeBeads]

Arrow Springs also sells the larger rods - I just got some this week.


Aimee