Posts Tagged ‘96 COE’
What is Frit?
If you've been around lampwork beads very long, you'll have heard the term frit. But what exactly is frit, and why do some of us go ga-ga over it?
Frit is an addictive tool in the lampworker's box of tricks, so let's talk about it today.
First -- What is Frit Anyway?
Frit is a term for ground glass. It can be ground as fine as powder, or can be coarse as large gravel. Somewhere in-between is where most of the frit action happens with lampwork.
Now here's a photo of some frit that I made up myself. I bought some single colors, then I combined a few of them together. If I recall correctly, this one had 4 different glass colors in it. Most of it is size 1, which is about like medium-grind coffee in size and texture.
You can buy frit in single colors, or in ready-made blends. It's available in COEs 33, 90, 96 and 104.
Using Frit
So now you have some of this stuff -- how in the world do you use it? And for that matter, why would you want to use it?
Because of the wonderful designs it can create in your glass beads!
To the left are some beads I made with some frit; I believe I got the frit blend from Robin at Glass Diversions. (While I still enjoy creating my own blends, I also still like to buy some from other people.)
You can roll the beads in frit lightly (like I did with this white set) or you can roll it on very thickly for a completely different look.
You can swirl the melted frit, rake it, make it into frit twisties and use those for decoration -- the possibilities are endless!
And if you like, get some fine clear frit and make sugar beads out of them! That is, roll the hot beads in the clear frit and just barely melt it in. It looks like it's sugar-coated!
I do have to warn you, though -- frit is addicting to use! I myself probably have more than 50 colors and blends. I know people who have many, many more.
Mixing COEs in Frit
This is a touchy subject for the most part. Some people say never, ever mix different COEs (frit versus base bead) and others say a little is OK -- like a light roll in 96 COE frit on a 104 COE base bead.
You'll have to make up your own mind on that, but here are my general rules:
- COE 33 frit can be used on boro beads only.
- COE 90 frit can be used on Bullseye beads only.
- COE 96 frit can be used on both Bullseye and soft (COE 104) glass in small amounts. And of course used with abandon on COE 96 base beads.
- COE 104 frit can be used on a base bead of COE 104.
You'll have to read all the arguements for and against, make some test beads, then decide for yourself. Like I said, these are my general rules, and so far they have worked well for me.
Well, that's it for now. You can look in my lampwork galleries for examples of other frit beads I've made. Come to think of it, I should devote a page just for frit beads!
Meanwhile, here's some frit that I found on ebay, both the actual frit and beads made with it. Enjoy!
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 System 96 Med Frit COE Glass WHITE OPAL 0200  US $3.19
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 BIRDBRAIN1258 Saucer HumBird Fdr Copper Frit US $35.63
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 Ladies First Jabo Glass Marble blue yellow black gold lutz frit US $2.00
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 Legand of Mary Gregory White Frit HP Cobalt CREAMER US $48.75
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 System 96 Med Frit COE Glass LT GREEN TRANS 0121 Jar US $7.99
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 System 96 Med Frit COE Glass PLUM OPAL 0520 Jar US $7.99
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 System 96 Med Frit COE Glass GRENADINE RED 0612 Jar US $7.99
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 System 96 Med Frit COE Glass PALE GRAY TRANS 1808 Jar US $7.99
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 Aluminum y shaped frit filter US $5.00
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What is Glass COE?
So what is glass COE? You see it listed in auctions and Etsy, you hear references to COE, but what does it mean? Let's talk about it, and why it's important.
What is Glass COE?
COE, when talking about glass, stands for coefficient of thermal expansion. In other words, how much and how fast glass expands and contracts, based on its makup. Since different kinds of glasses do use different ingredients, each rod of glass has its own rate.
In general, you'll most often see the following COE numbers:
- 104 -- soft glasses like Effetre, Vetrofond, Lauscha, Double Helix, CIM, Precision...I could go on and on. It's by far the most popular type of glass for lampwork beadmaking.
- 96 -- Uboros, System 96 and CIM are three names you'll see most often, but there are others. And while some people include the Zimmerman and Richenbach glasses here, they really do have a COE closer to 94.
- 90 -- Bullseye is the glass of note here.
- 33-34 -- Borosilicate. Also known as pyrex and boro. Northstar, Glass Alchemy, Momka's are three of the top names in colored boro, while Simax and Pyrex are two of the clears.
- Other -- This category includes the real softies like Satake and Kinara, plus Czech (Ornela) glass. They have COEs anywhere from 106 though 120.
Glass Rods, Mostly COE 104
The most important rule if you don't want broken beads: do not mix glasses of two different COEs in the same bead. Although shortly you'll see some exceptions to this rule.
COE Versus Viscosity
Now if COE was all you had to worry about, life would be grand in the bead-making world. But sometimes you'll find that two glasses with the same COE don't play nice together. And the culprit is usually viscosity.
I have a hard time explaining viscosity with how it relates to glass, so I'll use an example with foods. Take a tablespoon of milk and a tablespoon of honey and pour them into a bowl. The milk pours out quickly, while the honey takes its time oozing out of the spoon. The honey is more viscous than the milk.
(Okay, it's not a perfect example, but now you can get a mental image of viscosity.)
A good glass example of viscosity is comparing Effetre pastel white against Lauscha clear. Effetre pastel white melts fast and can get drippy very easily. Lauscha clear is much stiffer and is more like honey when it melts.
While I don't know for certain, I suspect that viscosity effects COE; in other words, a more viscous glass has a lower COE. And within a glass type (example, glass with a COE of 104), the tolerance is generally 2 points. So what that means is that a glass can be labeled 104, but actually have a range of between 102 and 106.
So, if you combine a 104 glass that's actually 102 and a 104 glass that's actually 106...you get incompatibility and a cracked bead.
Is it Ever Safe to Mix COEs?
I want to say first off is that there is a lot of controversy over this. Some say that you never, ever want to mix glasses of two different COEs, even in minute amounts.
Others say that it's acceptable to mix a tiny bit of a leaded glass (usually a frit made from a 94-96 COE glass) with, say, a base bead of 104 glass. The emphasis on the word tiny.
The only thing I can say about this is from my own experience as a bead-buyer and a bead-seller. I have beads from around 2002 that have some frit on them that appears to be the 94-96 glass that are unbroken. I have made beads that include a tiny bit of 94-96 COE glass that for 5 years haven't cracked or split.
Does that mean they won't crack or split 20 years from now? Don't know, but you can check back for a report then!
In my case, I work mostly with COE 104. Therefore, I label each and every rod that is not COE 104 with its color and COE. Glass can all look the same after awhile; best to play safe.
Well that's it for today with the topic of "what is glass COE". Here are some examples of lampworking glasses in various COEs and colors.
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 Glass Rod Flint 5mm od x 295L 5 lb approx65 pcs US $25.00
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 Glass Blowing Boro rod Tubing Beginners Bundle Lampworking US $23.25
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 Northstar glass glasstique off color rod glassblowing US $29.95
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 13mm glass rod US $30.00
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 104COE Moretti Randomly Selected Glass Rod Assortment 15 Pounds 65 SALE US $183.25
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 Glass Lampwork Bead Making Design Kit Tool Glass Rod DVD Torch DIY Fireworks Lot US $189.99
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 Mercadante Cobalt Blue Borosilicate Glass Rod 1lb 25mm US $.99
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 Bullseye Glass Transparent Rod 1 4lb COE 90 Lampworking US $6.63
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 Bullseye Glass Opalescent Rod 1 4lb COE 90 Lampworking US $6.63
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