F.C. Gold Casting

[dmonwaxa]

Woot woot CRob. Lil Rob you need to go back to school and sit in the corner, while you're at it face the wall,,,,LOL I knew someone would respond that way ,,,, but not you. I'm so so so dissappointed and broken hearted.

 

[charles007]

These are the little everyday problems.........

FOR THE HARD TO SOLVE PROBLEMS... I ALWAYS GO TO THE CLOSET AND GET OUT MY SUPER MAN CAPE ............IT WORKS LIKE A CHARM..........ITS CALLED EXPERIENCE....... AND AS AL CALLS IT.........I'M OLD AS DIRT!!!!!!!! hehe

 

[dmonwaxa]

Whip Mix Corporation Dental Products

 

[dmonwaxa]

These are the little everyday problems.........

FOR THE HARD TO SOLVE PROBLEMS... I ALWAYS GO TO THE CLOSET AND GET OUT MY SUPER MAN CAPE ............IT WORKS LIKE A CHARM..........ITS CALLED EXPERIENCE....... AND AS AL CALLS IT.........I'M OLD AS DIRT!!!!!!!! hehe

Me too Charles...Old but not quite old as dirt,,,, maybe bout two days younger.

 

[TheLabGuy]

As I'm in my corner looking over my shoulder staring at all the cool kids.......I must say, I'm sorry, I'm not worthy, it is "hygroscopic".......and my Tigers are getting rained out, what a night, time to go paintball the neighbors squirrels, that always put a smile on my face.....pink squirrels

 

[kcdt]

My gosh Charles, there must be an echo in here or this is dejavu. Someone who finally side with me. Yes burnout is at 900 when using the "hygroscopic" technique to achieve expansion, I believe it was 100F or 105F at 45 mins. if my memory serves me right. High heat technique; Hi temp 1200F. Since Beautycast is a gypsum based investment it does not hold up well to prolonged high temps unlike phosphate bonded type investments. Like you, I think the temp of the melt should be of concern since oxygen is being used. Oxygen of high burn out temp and high melting temp causes the metal to boil per se in the mold. The outer surface solidifies and the internal bulk of the metal remains molten which causes unusal strain in the matrix resulting in voids in the casting. Now the extent to which this happens is depedent on two variables; time and temp. Can I get an amen.

At one point I used a propane/compressed air set up because oxygen can easily overheat, but c/a never will.

 

[CatamountRob]

Rob,
You need to trade in the paintball gun for a .22 I like "red" squirrels better than pink ones.

 

[TheLabGuy]

Rob,
You'd laugh, all my neighbors have different paintball colors and that's what we do when we get bored, sit around and shoot all the damn squirrels.......I picked pink, the neighbor to the left has fluorescent green and the neighbor across the street has blue.........that we can tell who shot what ......you gotta love being a wood tick.

 

[dmonwaxa]

Rob, you guys are too much. Shooting squirrels? Aren't you in time out?.......LOL. You looked the word up didn't you, you probably thought i was cookoo.

 

[user name]

Back to topic...Problem solved. Contaminated Crucible.

 

[sixonice]

Back to topic...Problem solved. Contaminated Crucible.

nice! glad you solved the problem. i would still recommend burning out your full-cast invested in beauty cast between 900-1000F.

 

[user name]

Let me ask another related question...In the 'old days', we used a piece of asbestos ring liner, moistened and adapted to the bottom of the crucible. for some reason somtimes we'd sprinkle borax in a crucible and fan it with the torch to put a glassy surface on it. I know Im getting old because I remember learning that, but what was the 'why'? Im guessing old time crucibles werent pure and caused contamination?? Does anyone still do that? I use quartz for my NP, and clay for gold. Dont know why...what do you use?

 

[charles007]

This old timer still has a salt shaker of borax thats at least 20 years old, and I still use it(sprinkle on) only on type 3 gold......it cleans up the gold.....no asbestos in my lab in ? years........

That nasty crucible of yours.... tell the boss there are better ways to save money....I've never heard of that problem before.........
Dirty crucible on metal ceramics will cause a l o n g list of problems.........

 

[Clear Precision Dental]

I also use Borax on my crucibles. It works great for gold (sprinkle, just like Charles). I also "season" all of my crucibles (except for the graphite lined ones) even for my induction casting machine... I put brand new crucibles in my burnout oven, run 'em up to about 1000 then pull them out and sprinkle the insides with Borax to gloss 'em up real nice and shiney! Makes removing any residual alloy easy and the crucibles look "new" for a long time!

 

[user name]

Do you guys use quartz crucibles for everything, or clay for gold? Ive never heard of a graphite lined crucible..is that for induction or centrifical?