Spreadsheet additions?

[Paul Stout]

I've just put together a spread sheet for calculating L.E.C. (I know; its a guide not gospel) Is anyone willing to share any additional expansion values for things like strontium, or any other potentially useful ingredients, beyond what's listed in 'Modern Glass Practice' and 'Glass Notes IV'? Or have a suggestion of where to look for such additional values? Thanks in advance.
P.S. the original E&T values were published in 1927 in the Journal of the American Ceramic Society volume 10, pg. 551. It's a well written piece of history.

[Pete VanderLaan]

Look at Appen.

[Josh Bernbaum]

I think Dave Bross mentioned here somewhere that strontium and barium were very similar on expansion factor. So I've been entering the strontium in the barium line of the spreadsheet. How accurate that is, I'm not sure yet but is what I've been doing on the spreadsheet for these phosphates I'm doing now which have a decent amt. of strontium.

[Dave Bross]

Yup, what Josh said, I've got Barium at 1.40 and Strontium at 1.38.

One other you might not have, Phosphorous, P2O5, I have at .667

What's interesting to me is that as long as you're close, and you don't change the values for anything in the spreadsheet over time, your corrections getting to a match will take care of minor, and some major errors.

My opinion of the single most valuable aspect of a spreadsheet is in making those corrections to get a match with minimum tries.

[Pete VanderLaan]

that's interesting with the phosphate. It suggests a negative factor except that you can't just add P205. It needs to be attached to something which would throw the factor off. It is worth noting that calcium has a pretty low factor and that helps explain why one could add up to 5% cal phosphate without mismatch.

Of course then there are the ryolite stones.

[Dave Bross]

I wrote it that way because the spreadsheet I made breaks every material into it's components then E&T factors each individual component.

[Jed Hannay]

Originally Posted by Paul Stout

I've just put together a spread sheet for calculating L.E.C. (I know; its a guide not gospel) Is anyone willing to share any additional expansion values for things like strontium, or any other potentially useful ingredients, beyond what's listed in 'Modern Glass Practice' and 'Glass Notes IV'? Or have a suggestion of where to look for such additional values? Thanks in advance.
P.S. the original E&T values were published in 1927 in the Journal of the American Ceramic Society volume 10, pg. 551. It's a well written piece of history.

I've got Strontium down as 1.6 in the Appen Factors.

Appen plays out better for me than E&T, delivering estimates that look like the imaginary numbers I'm looking for and track ok with reasonable percent component changes. Lithium tracks better an Appen for me in particular.

Here's a bloc of numbers for common components related to the Appen estimates if you'd like to run your numbers through it. There's many additional oxides in the Appen list that I've excluded for simplicity. B2O3 requires a proportion subcalc but it's probably -.5 in SLS glasses. (I could be wrong. )

Oxide Molecular Weight Appen Factor
SiO2 60.08 / 0.38
Al2O3 101.96 / -0.3
B2O3 69.62 / -0.5
Li2O 29.87 / 2.7
Na2O 61.97 / 3.95
K2O 94.2 / 4.65
CaO 56.08 / 1.3
MgO 40.31 / 0.6
ZnO 81.37 / 0.5
SrO 103.62 / 1.6

"Calculating" is a strong word. It's an estimate, but it's an estimate that gives you something to think about relative to whatever other testing parameters you employ.

[Andrew Horch]

Has anyone tried to combine thermal expansion coefficients from difference sources? I found a website with thermal coefficients for a lot of materials at 25C ( https://www.msesupplies.com/pages/li...ered-materials ). I correlated the MSE 25C coefficients with Appen 400C ( https://glassproperties.com/expansio...ion-Models.htm ) and some other numbers I have. I got a very good correlation. Extrapolating from 25C to 400C is a big jump, but they do correlate well. I am not talking about using the MSE numbers directly, but either scaling the numbers or finding something that is roughly equivalent and do a 1:1 replacement. The goal is not perfection, but to get close enough that it only takes a few runs to achieve compatibility. Is using 25C data a reasonable starting point or is it a waist of time to use the low temp coefficients for anything?

[Pete VanderLaan]

try to stick to 19-300C and avoid the apples and oranges.

[Pete VanderLaan]

Go try out your theories. Make some glass bodies based on your concepts. Glass has an interesting way to make plain whether things are working or not.

[Ron Mynatt]

Where would I find a copy of Appen

[Pete VanderLaan]

I got mine out of Vargin on enamels. I'll poke around for another source.It shouldn't be hard.
Maybe in Volf? It sure does not show up obviously in a goggle search.