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LDent
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Greetings all, Perhaps someone can pinpoint the problem Ive been experiencing for the last few months.
1)Porcelain: Noritake EX-3. Alloy:Bego wirobond 280.
2)Slight greening in crucible from previous casting.
3)Ingot melting time and technique duplicated and mimicked as indicated on Bego website video.
4)Only New metal used.
5)Tried both 110 pu and 250 pu grain for sandblasting
6)Steam cleaned
7)Then Ultrasonically cleaned copings for 5-7 mins
8)Air-dried completely before application of POBA (paste opaque base)--->2 bakes
9)Applied same thickness of Shade opaque as required for Semi-Precious alloys--->1 bake
10)Increased recomended manufacturers drying time by 2 mins
11)Decreased start temperature to 400 degrees C. as per Noritake troubleshooting guide
12)Tried to purge 2 furnaces with carbon to aid in chamber de-contamination.
Problem persists... IRREGULARLY!!! Hit or miss. Bubbles appear after 2nd body bake or glaze bake, particularly common around margin area (thin porcelain area).
I am about to change all burs for metal finishing (once again) to make absolutely certain that there is no cross contamination.
Does anybody have any other suggestions to fix this problem after all of those steps are performed and problem persists?
A solution would be greatly appreciated!!!!
1)Porcelain: Noritake EX-3. Alloy:Bego wirobond 280.
2)Slight greening in crucible from previous casting.
3)Ingot melting time and technique duplicated and mimicked as indicated on Bego website video.
4)Only New metal used.
5)Tried both 110 pu and 250 pu grain for sandblasting
6)Steam cleaned
7)Then Ultrasonically cleaned copings for 5-7 mins
8)Air-dried completely before application of POBA (paste opaque base)--->2 bakes
9)Applied same thickness of Shade opaque as required for Semi-Precious alloys--->1 bake
10)Increased recomended manufacturers drying time by 2 mins
11)Decreased start temperature to 400 degrees C. as per Noritake troubleshooting guide
12)Tried to purge 2 furnaces with carbon to aid in chamber de-contamination.
Problem persists... IRREGULARLY!!! Hit or miss. Bubbles appear after 2nd body bake or glaze bake, particularly common around margin area (thin porcelain area).
I am about to change all burs for metal finishing (once again) to make absolutely certain that there is no cross contamination.
Does anybody have any other suggestions to fix this problem after all of those steps are performed and problem persists?
A solution would be greatly appreciated!!!!