Lost wax casting help sought

Greetings to all the Casters out there,
It seems that all the ingredients required, except for de-bubblizer,
are now assembled for my first lost wax casting in years. When I did
this before all my castings came out well. This was because of the
good instruction and equipment available at the time, not my skill.
I've tried to duplicate the equipment I used years ago. For
instruction it will have to be books and advice. The casting will be
done on a horizontal centrifugal casting machine. This is the way I
learned. The machine I have now is made by Lucas. It is very similar
to the Kerr machine I used years ago. The metals to be cast first will
be silicon bronze and sterling silver. I have some questions though.
What's a good recipe for debubblizer? 1/2 soap and 1/2 water?
What temperature should the flask be when casting silver and bronze?
The first castings will be at the most 3 ounces. With a Kerr type of
caster how many turns should the caster be wound up?
When melting the metal in the crucible I'll be using an air/acetylene
torch. I remember using flux, boric acid powder, when casting silver.
I don't remember if it's added near the end of melting or when the
metal is hot enough for the flux to melt.
I never did any centrifugal casting of silicon bronze. Only gold and
silver. Does the bronze need to be fluxed the way silver is? Is the
same flux used?
When casting years ago we used different crucibles for different
metals. But I don't remember any metal sticking in the crucible. Are
different crucibles advisable for bronze and silver?
I want to do some aluminum castings too but not right away. Is a
different crucible needed for aluminum?
I'm a machinist by trade with many years experience. Some facets of
jewelry making involve standard machining techniques. Please feel free
to ask me any questions regarding machining of metals and plastics.
Then maybe I can pay back for advice on casting.
That's it for now.
Thank You,
Eric R Snow,
E T Precision Machine

"Eric R Snow" wrote in message
news Greetings to all the Casters out there,
It seems that all the ingredients required, except for de-bubblizer,
are now assembled for my first lost wax casting in years. When I did
this before all my castings came out well. This was because of the
good instruction and equipment available at the time, not my skill.
I've tried to duplicate the equipment I used years ago. For
instruction it will have to be books and advice. The casting will be
done on a horizontal centrifugal casting machine. This is the way I
learned. The machine I have now is made by Lucas. It is very similar
to the Kerr machine I used years ago. The metals to be cast first will
be silicon bronze and sterling silver. I have some questions though.
What's a good recipe for debubblizer? 1/2 soap and 1/2 water?

[I think that makes "bubblizer". Debubblizer is alcohol-based, with some
tincture of green soap (available at well-stocked pharmacies) mixed in.
That's used if you aren't vacuuming the waxes after investing. If you plan
to do that, then use something else, since any soap-based material will make
bubbles in that circumstance. I've always used Vacu-film, a proprietary
mixture for this - maybe someone else has a home-brew recipe.]

What temperature should the flask be when casting silver and bronze?

[I've gone with 950F for delicate patterns in silver, 900 for heavier ones.
Bronze can be about 100 degrees cooler.]

The first castings will be at the most 3 ounces. With a Kerr type of
caster how many turns should the caster be wound up?

[That will vary according to your spring. Try 2 turns and see how it goes.
If the metal splashes out before it enters the mold, back off to one and a
half turns. If it's not enough - if the mold doesn't fill - give it another
half-turn.]

When melting the metal in the crucible I'll be using an air/acetylene
torch. I remember using flux, boric acid powder, when casting silver.
I don't remember if it's added near the end of melting or when the
metal is hot enough for the flux to melt.

[I heat the metal enough so that the flux sticks when you sprinkle it on.
Otherwise, it blows away.]

I never did any centrifugal casting of silicon bronze. Only gold and
silver. Does the bronze need to be fluxed the way silver is? Is the
same flux used?

[No, silicon bronze doesn't need flux; it makes its own.]

When casting years ago we used different crucibles for different
metals. But I don't remember any metal sticking in the crucible. Are
different crucibles advisable for bronze and silver?

[Yes.]

I want to do some aluminum castings too but not right away. Is a
different crucible needed for aluminum?

[Definitely. Small quantities of aluminum do weird things to other metals.]

I'm a machinist by trade with many years experience. Some facets of
jewelry making involve standard machining techniques. Please feel free
to ask me any questions regarding machining of metals and plastics.
Then maybe I can pay back for advice on casting.
That's it for now.
Thank You,
Eric R Snow,
E T Precision Machine

[I might be calling that one in very soon - I'm just getting into plastics
machining, and there's a lot I don't know about it.]

Andrew Werby
www.unitedartworks.com

On Sun, 18 Dec 2005 19:54:04 GMT, (Eric R Snow)
wrote:

Greetings to all the Casters out there,
With a Kerr type of
caster how many turns should the caster be wound up?
When melting the metal in the crucible I'll be using an air/acetylene
torch. I remember using flux, boric acid powder, when casting silver.
I don't remember if it's added near the end of melting or when the
metal is hot enough for the flux to melt.

Our standard practice at Kerr was to wind the caster three turns, and
flux was added at the end of melting. This was for consistency
purposes; identical test procedures for all batches of refractory was
more important than field results. (I spent several years as manage of
quality control for Kerr Refractories, before they became a part of
Sybron Corp. and no longer promoted from inside...)

Blessed be, for sure...