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Old 07-09-2018, 08:50 PM
Dave Bross Dave Bross is offline
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You always have to adjust any recipe for each individual furnace, location, elevation, humidity levels, phase of the moon....no, wait, just kidding on the moon.

Each furnace evaporates different quantities of the alkalai as the batch melts, depending on how powerful the furnace is and then the other variables like elevation, etc. kick in on how much of the alkalai goes away. Two identical furnaces in the same shop may want a different calculated number for each furnace. Move one furnace across the street and you'll probably need to recalculate again.

Those clear recipes are quite simple to mix. Try them with bucket/paint mixer for mixing in a small trial quantity if you're worried about screwing up.
Use the check boxes on my spreadsheet to log each chemical as you add it because that's the most likely screw up.
The other elephant in the room there is moisture in the chemicals and that's easily corrected.
Try them and you'll be amazed.
You can also scale working characteristics over a wide range by varying the lithium.

Yes, I would be VERY wary of any batch lacking alumina. You can get around using alumina with things like zinc or more calcium but I much prefer the insurance provided by the alumina.

Some day in the (very?)near future the high lead colors are going away, along with the leeway on mismatch they provide. Being able to batch and match will become priceless then. As you now realize, all these pre-mixed batches do not fit all colors, the lead is letting everyone off the hook on actually matching the glasses.
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Last edited by Dave Bross; 07-09-2018 at 08:58 PM.
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