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Old 03-21-2019, 10:40 PM
Ron Mynatt Ron Mynatt is offline
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Garage temp

In glass notes they describe a Garage design but not what Temp to run it at.Instead of building a garage to park a piece of glass before adding it to a another piece would a Denver pot furnace be a possible sub?What temp should I set it to?My clear glass starts to slump if I hold it too long above 975.
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Old 03-21-2019, 10:50 PM
Jordan Kube Jordan Kube is offline
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There's your answer.

Depends on your glass, burner placement, thermocouple placement, garage geometry, etc, etc. Stuff cracking? Turn it up or hold a little longer on the hot side. Stuff slumping on the cold side? Turn it down or open up the door a bit.
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Old 03-21-2019, 11:30 PM
Nick Delmatto Nick Delmatto is offline
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89 COE. You don't state your glass COE. Most of the rest of you work in 93-96 COE which I did also until 2008 when I bought my l lifetime supply of 89 COE cullet from Lancaster Glass (Ohio). I use it un-altered & have gotten used to using it as is, which is shorter work time than studio norm & not as bright a clear glass...all that considered, my annealing temp is 900F & my garage pickup temp is 900 to 925F, depending on thickness. Let me know if any 89'ers have any questions.
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Old 03-22-2019, 07:23 AM
Eben Horton Eben Horton is offline
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Ideally your garage is about 3 feet long and almost 2 feet deep. Your pipe burner is on the left side and there are 2 doors that are open at running temp. You want the left side to be just below your slump temp and the right side to be right around annealing temp. WHen you make something, you put it in the right side and then you shuffle it over to the left side before you take it out. If you build one like this you now have an amazing pizza oven.
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Old 03-22-2019, 12:28 PM
Ron Mynatt Ron Mynatt is offline
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94 is the calculated coe
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Old 03-22-2019, 12:58 PM
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Quote:
Originally Posted by Ron Mynatt View Post
94 is the calculated coe
****
That's an important number since it is quite a distance from Kugler opaques (89.5 APPROX) as well as Gaffer in general (ABOUT 96.) . It would match sys96 ( a true 94.1) pretty well though. Who did the physical as opposed to the measured Linear expansion coefficient results?
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Old 03-22-2019, 01:05 PM
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Here's how Italians do it (i.e. how Lino would do it).

Don't bother with "COE", calculated whatever.

Drop a cookie on the marver. Grasp with diamonds and hold mass down on marver while pulling up on punty. Pull up to a cane about 1/4" thick. Cut the cane so it is just tall enough for the garage height (should almost touch the ceiling). Position it dead center (between openings) all the way to the back wall of garage. If the temp is right just the first 2.5 to 3" of the vertical cane should slump over (see my awesome diagrams).

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IMG_1740.jpg
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Old 03-23-2019, 08:50 PM
Ron Mynatt Ron Mynatt is offline
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So I trying to understand Peter you mention physical as oppose to measured lec How does a calculated lec compare to these? Spruce pine says "Labino Formula has a theoretical expansion of 87.3 x 10-7, with a measured expansion of 96-97 when melted.Is the 87.3 the calculated lec or is the 96-97 .It seems that the 87.3 is close to Kugler but the 96-97 is far away from Kugler. Since Kugler contains lead it should work with a broader range of soda lime glasses.I have never had a problem of compatibility with Kugler, Q or Reichenbach but someone might say just give it time. I have pieces 20 years old that show no signs of incompatibility . The spreadsheet I use gives me a coe or lec of 94, that is calculated but not measured number .
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Old 03-24-2019, 08:08 AM
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Measuring is a physical test with a rod 4.000 taken from 19-300C. Calculated is based on the expansion factors developed by E&T back around 1925. Kuglers opaques really are measured around an 89 and they don't fit SP87. They fit SP83 OK.

It's a question of the temperature range used in the actual test. What you see is the set of factors used by English and Turner to calculate the factors. What various tests have done is to change the scale in which the tests occur. As an example the Winkleman and Schott research was done for the enamel industry and measured between 19C and 200C. The range used for the E&T factors is 19C to 300C. That explains the change. Appen has a different set of factors for all the appropriate materials as well.
The expansion is linear which explains the term L.E.C. Coe is not defining anything and it's why I object to it. Expansion is why it's impossible to really fill your pot. That expansion keeps on going but since the glass is molten at a certain stage, you can't measure it, but you can do the math.
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Old 03-24-2019, 12:38 PM
Ron Mynatt Ron Mynatt is offline
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Thanks for that answer. That helps clear up some things with glass calculations. Ron
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Old 03-25-2019, 07:20 AM
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well it does and it doesn't. Using Appen's numbers will be more real world. I recall when Lithium was finally awarded a 4.90. That changed a lot of stuff. Appen also has factors for the metallic oxides which E&T do not. I don't use them but they are there.
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Old 03-26-2019, 12:46 PM
Ron Mynatt Ron Mynatt is offline
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Yes I had to adjust my calculations on my spread sheet to reflect the new lithium factor.
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Old 03-26-2019, 01:07 PM
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I credit Croucher with that number but I don't know the derivation.
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