Lots of cracked beads when I use frit

[cherylsart]

I've been collecting frit blends lately, and though they are fun to work with, I'm having a lot of trouble with them cracking in half along the hole. I'm thinking it's because I am putting coe 96 frit on 104 glass. Anyone else think this might be the problem? I'd like to get some 96 rods. Can anyone recommend a supplier? No ebay; I can't do business with them right now.

Thanks!

Cheryl

[bead crazy]

Sounds like thermal shock. When I used to much frit I got cracks but it was all over cracks.

[Mr. Smiley]

If it's breaking along the mandrel, it's thermal shock. Either the bead is too cool when you are putting it in the kiln or your ramping down too fast.

[DesertDreamer]

Sounds like you're admiring them for too long.

96 frit blends over Moretti CAN crack, but usually it's if you're using several heavy layers. You can't entirely encase a 104 bead in non-104 frit. A few passes, melted-in, though, with at least 50% of the base color exposed (I think of it as peeking out) should be fine. If you DO get compatibility cracks, they're usually along the surface where the frit and base colors are in tension. I've had some over-fritted beads actually flake off the frit. Dramatic rejection!

[cherylsart]

Oh, ok, I get it. I don't have a kiln; they go into a bucket of perlite that I've had for a while and it's getting powdery. Maybe I need to replace it? I try to put them into the bucket just as the glow is almost gone, but I fear that I'll get dents from the perlite if I put them in too soon. I think I'll get a new bag of perlite or vermiculite and see if that helps because it's been happening more lately. I'm still thinking about getting some 96 rods, at least in white, black and clear, if I can find out where to get them.

Thanks!

Cheryl

[DesertDreamer]

How big are your beads? That makes a difference. Smaller round beads (under maybe 1/2") seem to survive pretty well. But as you get larger, or move into different shapes, you're starting to risk seriously uneven cooling. And mixing COEs without a genuine annealing cycle is likely a kiss of death anyway.

Arrow Springs sells Uroboros (excellent basic 96 COE glass, even a good clear). Spiral Dance is having a closeout and according the the email I got yesterday she'll be selling the remainder of her Uroboros at a discount, as well. Might be a very good time to give 96 a try. Make sure you get black, white, clear, AND almond...it's a lovely creamy off-white and isn't reactive.

[Toni Lutman]

Are these pressed beads? Keep in mind that pressed beads will be more likely to thermal crack (especially if not going straight into a kiln) since the glass is thinner at the mandrel, and the bead doesn't cool evenly.

[bclogan]

OCR is also another good place to get 96 glass... Reichenbach, Zimmerman, System 96 (Uroboros).... Yummmm!

[cherylsart]

Yes! They are pressed beads. Ok, I'm beginning to see a pattern here and I'm thinking about things I can do to minimize the problem. I had hoped to have a kiln by now but unexpected expenses have put that purchase on hold till the end of October at the earliest. At least I know for sure which kiln I'm getting!

Thanks everyone. What is OCR?

Cheryl

[Starrr]

Olympic Color Rod

[ellyloo]

yeah, i just had to throw out a nice set because i over fritted. You start seeing shiny cracklines on the borders of the frit and when I tapped it with another bead, a chip came off.

[Listenup]

I would put it in the pearlite/vermiculite long before it starts to lose the glow. To find out if it's OK to put in yet, give it a gentle tap against the torch head or your marver, or even the press. If it gives a light tap sound, you can put it in the pearlite. If it doesn't, it's still too soft.

[beadsoncypress]

I solved this by using a crockpot filled with vermiculite. Then, turn it off when I am done for the night and cover it with some fiber blanket and let cool. I batch anneal every couple of days rather than running the kiln when I am torching (saves a little $$).
susan

[Ofilia]

I don't generally use presses, but have had this problem of craking along the mandrel line when I've made mask beads in the past. The break was instigated on the "thinner" side of the bead, the back, where it gets more mushed since I"m doing a lot of pressure to shape on the front.

Lets see if I can put a link to some mask beads from my site: http://www.ofiliaartglass.com/beads.htm Scroll down a little to see the masks....

What I did to help remedy that problem, was when I finished, the bead, and I am doing the overall "bathing" in the flame before putting it in the kiln, I give it some extra licks up and down that back side of the mandrel line with the flame a little more concentrated and last thing before it goes in the kiln. I had to remind myself, that this THINNER part of the glass would be the first to cool.

Ofilia

[cherylsart]

It sounds like I am letting it get too cool before dunking it in the vermiculite. I'll start putting them in sooner. Thanks for all the help and advice!

Cheryl

[dragon myst]

Bridgetown glass sell this glass too . They have good service too !

[Jane P]

Before I got my kiln, about 75% of my pressed beads (some with frit, some without) all broke in half. Now they go straight into the kiln as they are made, and the cracking problem is a thing of the past. I gave up doing pressed beads until my kiln arrived.
Until you get your kiln, perhaps it would be a good idea to just do round spacer type frit beads, and wait to do the pressed ones until you can put them straight into the hot kiln.

[Lisi]

I make a lot of frit beads and use mostly 96 COE as a base, just to be on the safe side. I still use 104 as a base, but prefer the smaller frit sizes like #0 and #00. One light layer of that and I don't worry too much. Some frit is just too "chunky" for me to take a chance on it with 104, so I use it with Uroboros.