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Flask casting temperature


#1

Please, which is the best temperature for small and large flask for
pouring 18kt gold? which is the best temperature for melt the 18kt
gold in a electric furnace before pouring it? please reply me.
thanks everybody


#2

In accordance with “Kerr Satin Cast 20” I am just
reading from their own sheet of paper, it doesn’t say how large or
small the flask is, but here goes…:>)

Gold 18 kt, yellow melting @ 1700 F ==>  flask casting @ 950 F
Gold  18kt, white   melting @ 1730 F ==>  flask casting @ 900 F

I also have the notes of wax burn-outs too for other
metals…Platinum <-> Silver, etc’s. extra notes here…!!!

  1. casting temps. should be approx. 100-150 F above melting temps.

  2. casting temps. will vary slightly depending upon particular alloy
    being used.

  3. pure Gold melts @1945 F

I really hope this helps you greatly, to me, it was just sitting in
my files waiting to be used…let ‘us’ all know if this works for
you…

“Gerry, the Cyber-Setter !”
www.gemzdiamondsetting.com


#3

Hi, In my experience, it is not the size of the flask that’s so
crucial but rather, what is held in the investment.

Lacy, thin objects are relatively tough to fill w/ molten metal
since, although there is not much air in the chamber (due to the
small size of the model), this air must evacuate the chamber very
quickly ahead of the incoming metal. In other words, the small mold
chamber fills very rapidly and the air inside must move out speedily.

On the other hand, a large mold cavity–like a gent’s signet ring–
fills relatively slowly, because it is so much larger. Not much back
pressure.

The lacy casting should have a higher flask temp when cast-- mqybe
1000 F-- since A) it is harder to fill and the metal might freeze at
lower flask temps before the mold fills and B) the fine cross section
allows the cast metal to cool relatively quickly which means that the
casting will not have excessive or coarse grain growth which
translates to brittleness and porosity.

Large mold cavities which are easier to fill can be cast at cooler
mold temps.–maybe 750 F-- and this lower temp allows this big mass
of metal to cool quickly, again without large grain growth.

Also remember that every metal has its optimum handling parameters.
Silver, although it always seems more fluid when molten, can be a
very finicky metal to cast and it is also lighter-- not having as
much inertial force in centrifugal casting or as much gravitational
advantage in vacuum casting.

Hope this helps,
Andy Cooperman


#4

I have a chart I can either mail or fax to you of temperatures for
different size flask’s

Andy “The Tool Guy” Kroungold
Sales/ Tools and Technical
Stuller Inc.
337-262-7700 ext. 4194
337-262-7791 fax
andy_kroungold@stuller.com