What does 104 coe mean?

[GlassyLynn]

Hi, I'm reading 104 coe everywhere, does that stand for something? I think it means its a soft glass, but are there other numbers? Are different numbers all compatible? Also, do different types of glass have different numbers depending on what color your getting?
Thanks.

[Kraaloog]

Hi Lynn,

All kinds of glass have their own COE. Sometimes they are compatible like Moretti (COE104) and Lauscha (I think COE 102-106). I don't really know what COE stands for, but I do know that, when you want to combine different kinds of glass, the COE has to be the same, or only slightly different. If not, the beads you make will surely crack, no matter how well you (flame)anneal them. Usually, when you are browsing the site of a glass supplier, the supplier mentions the COE numbers, so you'll know whether it's compatible with your own glass or not.

[Tink]

COE stands for co-efficient of expansion. Too many folks make the mistake of thinking that is the ONLY criteria by which to determine the compatiiliy of glasses.

We've been gone for several days, and I have a zillion things to catch up on. I'll check back on this thread later to see if anyone has given you a good, thorough answer. If not, I'll give it a shot.

PS - This link (http://www.cdvkiln.com/ris-bullseye.htm) will give you some wonderful information!

[suzanne]

COE is the expansionlevel of glass. A number is always stated as COE so you can tell what type of glass you are dealing with.

Moretti, lauscha , vetrofond and most Czech glass have a 104 COE.
Bullseye is somewhere around 90-92 coe
Reichenbach, Kugler, Zimmerman , Gaffer all have a COE somewhere between 92-60
Borosilicate has a 32 COE.

You can use differend COE's together but there are a few rules.

Rule number one: Never ever use bullseye with moretti , vetrofond, lauscha or czech glass
Rule number two: when using reichenbach, kugler, zimmerman or gaffer on other soft glass ( bullseye, moretti, vetrofond, lauscha or czech) always use the 5 % rule, don't use more then 5 % of the total weight of the bead ( this is a guessing game, only way to know if it will work is to just do it and see for yourself).
Rule number three: Never use Borosilicate with either of the brands named above, not compatible at all.
Rule number four: always label your glass rods to make sure you don;t accidently grab a different type of glass, your bead will definetly break when using for instance bullseye over moretti.

Suzanne

[suzanne]

Shoot, Tink beat me to it

[GlassyLynn]

Excellent info guys! I guess it's safe to say that all moretti and Vetrofond have the same coe unless it states otherwise. I knew about bullseye, but not the others, how fascinating this all is!

[lunamoonshadow]

And...some 104's DON'T play together :( Just to be difficult!
For example, a lot of the lauscha is "fussy" & not *really* exactly @ 104 (www.glassdaddy.com has some more info on that I think, so does the new lauscha site, can't remember the link--it's the sidebar ad with the blue-rods in it)
Moretti/Effetre alabasters don't often play well with other things....
Rubino can be fussy...
Bullseye is tested compatable with ITSELF *if* it's all rods--they mark their stained glass differently (read the catalog--it's fascinating!)
There's tons of tips on certain colors in here if you search a color too...just use the search function & put in the color you're interested in ;)...

[JanMD]

For a very short general discussion of glass compatibility and COE, entitled Glass Types and Forms: Beginning With a Discussion of Glass Compatibility, from WarmGlass, see: http://www.warmglass.com/Glass_compatibility.htm

For more detail, see the section entitled General Info, under "Glass: Technical Information", here: http://www.sgb-midatlantic.org/how-tos.html

For a lot more detail, buy and study Jim Kervin's book More Than You Ever Wanted To Know About Glass Beadmaking. I do have some small problems with it, but by and large, it's very good. I can recommend Bhandu Dunham's book Contemporary Lampworking: A Practical Guide to Shaping Glass in the Flame (3rd edition) unequivocally. That one is great. (For reviews, see: http://www.sgb-midatlantic.org/book_reviews.html)

Of course, the only way you are going to tell for certain that two glasses (or two colors of the same glass) are compatible is to test them yourself. Arrow Springs describes how to do that compatibility test here: http://www.arrowsprings.com/html/stringer_test_for_compatibilit.html

Hope this helps a bit to part the fog.

JanMD

[Raven]

So if one does a day of Bullseye glass will it still anneal in the kiln at the same temp as Moretti. I have a fugi controler on mine and I know it was programed with two programs. I was thinking that the seconed one was for Borsillica. One that I most likely will not be using for a long time due to the major price shift. So if anyone can answer this question I would appreciate it.
Thanks,
Raven

[adovbs]

So if one does a day of Bullseye glass will it still anneal in the kiln at the same temp as Moretti. I have a fugi controler on mine and I know it was programed with two programs. I was thinking that the seconed one was for Borsillica. One that I most likely will not be using for a long time due to the major price shift. So if anyone can answer this question I would appreciate it.
Thanks,
Raven

Moretti and Bullseye anneal at close to the same temps. I believe most folks use one schedule for both. I do as well, but I will increase the kiln garaging temp to 950-960 when I know I'm going to be working bullseye that day.

[Bob Torbett]

I've had a few beads I've made where I combined glass types break. As long as they are the same type they're fairly safe. I've been doing quite a bit of fusing and slumping with some of My wife's stained glass and have found out the hard way that you MUST check compatability or they WILL break. Besides getting some great info on this forum, I also was sent to the "Warm Glass" site and they have a great introduction to the basics of glass for almost all uses. They explain the COE in a way that realy is easy to understand. Check out my thread on this forum titled "Breaking While Slumping". The responses show the expertise and help everyone on this forum is to us beginners.
Bob