c.o.e.

[tilman]

COE = Coefficient of Expansion


has anyone wondered what this means or how this works? well here you go.

The COE number is actually a sort of shorthand. The 33 for Pyrex means 33 x 10-7 (or .0000032). This means that for every degree Celsius change of temperature, a one inch dimension of that glass will change .0000033 of an inch. (or put another way, Pyrex will contract or expand .00033% of its length for each degree C. of change)


foot note: 33 x 10-7 this means 33 x 10 to the power of negative 7

same goes for soft glass. just replace 33 for whatever the coe of your glass is (90-104)

i hope this helps somebody understand

[Alfred]

Thanks,hope that helps some people too

[HOSS]

COE = Coefficient of Expansion

[tilman]

thanks nemesis. i guess that would be important also. i changed the post to fit.

[pacosaki]

That is interesting. Thanks for the info!

[richsantaclaus]

Since the scientific notation has the same exponent, it is easier to realize that it is the 33 or the 104 that really makes the difference. 33 means that the molecules move in vibrations less than the 104 molecule vibrations and this is the reason the COE's will not mix. Occationally, one can get away with mixing 96 with 104 if they follow this "5% rule" when one applys 96 frit to the 104 glass or does an implosion. But, one is still taking a chance of the glass cracking.

Here is an example of a 96 frit imploded flower marble encased in 104 clear I made.

[UmaJulz]

Wow rich, how big is that? Is it still stable?

Also note that the COE that we refer to in glass, is the linear coefficient. When using enamels, they are not listed as the linear coefficient of expansion, but the cubic coefficient. Thompson's Enamels have started to do the conversion for us, how nice.

http://www.thompsonenamel.com/products/enamels/index.htm

[somewhere]

Here's a good read on the Origin of COE as compatibility measure in studio glass.

http://talk.craftweb.com/showthread.php?s=&threadid=3397&highlight=expansion+viscosity

and here:
http://talk.craftweb.com/showthread.php?s=&threadid=2314&highlight=Coefficient+of+Expansion

and more:
http://talk.craftweb.com/showthread.php?s=&threadid=3823&highlight=Coefficient+of+Expansion

You will read some of Robert Mickelsen's thoughts on coe.


Interesting read if your into history and science

[FredLight]

Interesting thread!!

Also CTE in other industries. Coefficient of Thermal Expansion.

[richsantaclaus]

UmaJulz - that soft glass marble is still in tact and is 1 1/8" in diameter approximately.