casting

[artexdentallab]

npg casting

it is difficult for me to casting npg metal (non precious gold metal

 

[dmonwaxa]

yes you are confused. non precious gold? unless i'm missing something gold is a precious metal. Dental alloys can be classified as NP (non precious),N (Noble) and HN (high Noble)
NP containing no gold but may contain noble metals < 25% wt; Noble, content > 25% wt; High Noble, content > noble metals with at least 40% Gold(Au),hope this helps, good luck.

 

[artexdentallab]

yes you are confused. non precious gold? unless i'm missing something gold is a precious metal. Dental alloys can be classified as NP (non precious),N (Noble) and HN (high Noble)
NP containing no gold but may contain noble metals < 25% wt; Noble, content > 25% wt; High Noble, content > noble metals with at least 40% Gold(Au),hope this helps, good luck.

hi npg is noun prcios metal that is golden colour ofcourse one kinde it have 2%gold that its name is npg+2.this kind metal have aluminium

















+2

 

[dmonwaxa]

You may have to email the manufacturer for instructions. Info below.
sorry I could not be of greater help. I have not used alloys like that since lab school in 82.

NPG, NPG + 2—Aalba Dent Inc., 400 Watt Drive, Cordelia, Calif. 94585, 1-800-227-1332 begin_of_the_skype_highlighting 1-800-227-1332 end_of_the_skype_highlighting, "www.aalbadent.com"

 

[labguy50]

I used npg many many moons ago...you need to use a runner bar with tiny diameter chill vents/sprues off of several different areas of the crown or you will be fighting the porosity issue..hope this helps

 

[dmonwaxa]

I used npg many many moons ago...you need to use a runner bar with tiny diameter chill vents/sprues off of several different areas of the crown or you will be fighting the porosity issue..hope this helps

labguy50 can you show an example in waxup form. I used npg back in the 80's in school , forgot the technique. Thanks

 

[labguy50]

Sorry guys , new here and havent figured out how to post pics yet ...but ....picture the full gold crown waxup ...now...take some very small diameter round spool type wax like you would use for making finish lines when waxing rpd's on the refractory model....cut these into about 3-5 mm long and attach to mesial, distal, facial, and lingual,,,also use a reservior sprue along with runner bar...sounds extreme i know but it works well...thicker the crown the more rods you attach to the crown...its the only way i could get porosity free castings with the stuff

 

[Gdentallab]

have you followed the manufacturer instructions?
Have you used the right temperature for burn out, and casting?
I usually cast it at low temperature , it works fine.
Burn out till 800 ¤C or even less)
Heat the npg at a temp even lower than when you melt gold alloys. And here you go.