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Old 10-07-2019, 05:11 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 21,506
Pete VanderLaan is on a distinguished road
How one melts makes a difference and it's not insignificant.

Back when I had the little studio in the Santa Fe railyards, I would melt on sundays and one pot was 275lbs of my clear and another was a 75 lb of a copper ruby. I would work both of those pots until midweek when at the end of the day, I needed more red, but the furnace was running at 2080F which is where I liked to work. I did actually want to go home so starting that cold, I loaded the red pot full of the batch glass. I did not return usually.

Now it's important to recognize that the red glass came out of the same batch barrel for both the sunday and the thursday melts. No changes. Identical mix from the same mixer.

The next day, I would use both glasses and the red was no longer compatible with the clear. This occurred several times before I started to dig in and change my process. If I turned the furnace up and waited until it was at least 2250F, there were no issues. It became clear to me how sensitive batch melts are looking at expansion/ temperature ranges.

The point there is that the two glasses are or were being melted in rather different environments, the big melter at Spectrum undoubtedly hotter than the Uroboros furnaces. It's worth considering. I don't ever try cold batch melts anymore unless they are fluorines with far lower viscosities.
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