Bubbles after second firing or glaze baking using NP metal

rkm rdt

rkm rdt

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If you grind a soft metal like cermaic gold with a stone, you can fold the soft metal over itself creating an air pocket. That is why they recommend using a carbide for ceramic golds.

If you are trimming a non precious alloy,use alumina oxide stones and make sure the surface area is not too coarse. In other words, finish using a fine stone so that the paste opaque flows over the surface and avoids trapping air.


Mix your paste opaque well and don't dilute it too much.
 
2thm8kr

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The binders in some AL02 stones can be a cause of contamination also.
 
rkm rdt

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Most of my pfm alloy is semi precious silver palladium. I use a heatless stone followed by white alumina oxide stones.

sandblast and opaque with no bubbles .I keep the surface fairly smooth with the stones and have had good results for as long as I can remember.
 
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No hands touch the metal framework before it goes through first firing. Start temp was lowered to 410 degrees C. I even exceeded the recommended 6 min dry time troubleshoot suggestion by Noritake manual to 8 mins. Had a discussion with GC Americas technical support yesterday about In Metal Bond. They said degassing was not necessary and that steaming raises the risk of contamination as many here have mentioned. I tried to order it through a distributer however, it hasnt yet been approved for use in Canada (red tape). Are there any other similar products to the IN Metalbond by other manufacturers? Bredents product sounds similar... Its pink too. How about other manufacturers paste opaques? Would this be a solution?
 
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2thm8kr

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Anyone have a plausible explanation about steaming contaminating the frameworks?
 
Tayebdental

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Anyone have a plausible explanation about steaming contaminating the frameworks?

I never steamed clean my metal, by the way I use semi precious metal alloy, what they are saying makes since, because if you start with a poorly finished metal surface you make it worst by forcing contaminant in those micro canyons on the metal surface to be stuck in there , while on the other hand ultra sonic cleaning will dislodge these contaminants out of the micro canyons, I think the problems they are having is with NP alloys. Many variables are involved two of them are casting techniques and metal finishing.
 
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No water if it is paste opaque.
 
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Anyone have a plausible explanation about steaming contaminating the frameworks?

The heating elements have a coating that contaminates the water. It doesn't matter what you paid for it or how much you want to believe its the right thing to do. Its filth.
 
2thm8kr

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Do you know what the coating is. No steam cleaner here.
 
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Do you know what the coating is. No steam cleaner here.

Im sorry, I don't. The topic was thrashed around some time back. There is one here who knows...Rob? Where are you brother?
 
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Im sorry, I don't. The topic was thrashed around some time back. There is one here who knows...Rob? Where are you brother?

Calcium carbonate i guess - just like in a kettle especially if you have "hard water" inyour area :(. I bet most don`t use distilled water !
 
Bumfrey

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I have used a steamer for ages using tap water. Had about 3 crowns with a bubble in about the last 4 years.
 
Bumfrey

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I am a bit scared now though....
 
Edy

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Let me tell you Bumfrey , a year ago i was using steamer too , had not even one bubble , i didnot knew what bubbles mean ehe . . . i bought renfert ultrasonic a few months now , and lately i got plenty of bubbles , the thing is that at the period i bought the ultrasonic , my torch which i melt alloy for casting got a problem (which of i realized indeed that its a problem only these last days) i opened the dizza (the head of the torch) and lots of black dust fell of out from it , since then i saw that torch its not producing for me the required flame is needed to melt the alloy , hence , i was spending a lot of time with the torch flame over the alloys till i get the melting -- burning the alloy which started to cause me these bubbles later on in the porcelain , so from this i came to conclusion that treating your alloys with torch casting and after to grind the alloy with a clean stones , its much more important then choosing steamer/ultrasonic .but like martin said , i put into my steamer back then only distilled water.
 
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Bumfrey

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O **** my torch looks really old. I will get a new one asap before it gives me problems. Only today i noticed its not firing up like it used too.
Thanks for the heads up.
 
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I tried to find similar products to the GC In Metal Bond since the distributers in Canada have a restriction selling that product. Apparently theres more bureaucratic red tape to go through before the product gets approved for sale here. It appears that Bredent also had a product called In Ceram Bond but this too has not yet been approved. With all these restrictions and red tape, one must wonder why outsourcing is such a problem these days. It seems that the National board of health wont stop the importation of "alien" crowns but instead, restricts the use of reputable products to aid in manufacturing home grown units.
Does anybody know of other products to use other than these two "pink" ones mentioned here?
 
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The best metal bonder is to just use a very small amount of your systems opaque, slightly thinned and don't just brush it on...go at it swirly and almost scrub it on so it gets worked into every microscopic undercut. Fire at your normal oxide temp. It needs to be a very thin application or you wont develop any oxide under it and will defeat the purpose.
 
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