bubbles bubbles bubbles...

magushnik

magushnik

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hey guys and gals, i'm having a problem. All of the sudden i'm getting porosity when doing veneers. i'm using the same refractory material i've always used and same porcelain. any suggestions/ideas?
 
wwcanoer

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excess water when removed from soaking before build-up???
 
TheLabGuy

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Usually if you're getting bubbles, it's a degassing issue. Do you degas your refractory models before you put porcelain on them?
Placing it in the oven while it's still hot?
Are you using a medium of any kind on the refractory?
 
Pronto

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How about the expiration date? We've had problems with that in the past.
 
magushnik

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thanks guys, yea i don't think its excess water, and the exp date is fine. i do think ultimatly the problem is degass, but i'm doing everything right. i'm degassing at 1900, too high, too low? could that be the issue?
 
wwcanoer

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I degass in hot burn out oven at 1472 20 min, then into porcelain oven run up to 1472 for 10 min, cool down then back into hot burn out at 1472 for 10 min. Using G-cera vest

good luck

Carol
 
Al.

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It could be your porc furnace temp is off a few degrees Making a slightly underfired first or second bake. That has happened to me in the past, mostly when it was a big case with a big refractory model. Large cases require a higher temp for the porc to fully mature. If not youll get a ton of tiny bubbles.
Is your furnace pulling full vacumn when you fire refactory veneers?
 
TheLabGuy

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It could be your porc furnace temp is off a few degrees Making a slightly underfired first or second bake. That has happened to me in the past, mostly when it was a big case with a big refractory model. Large cases require a higher temp for the porc to fully mature. If not youll get a ton of tiny bubbles.
Is your furnace pulling full vacumn when you fire refactory veneers?

Oh yeah......i forgot about that one, good job Al, turn the heat up........

Hey Al,
Spell check is free......hehehe
 

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