several sources I have for steam casting use a method of
attaching a round piece of 14 gauge metal wire(no more than 1/2
") from the sprue base to the model. It must be removed, of
course, before burnout. Have you casted this way and what are
the results? Also, one of the books recommends making a little
ball of wax at the bottom of the wax wire leading from the
model, and then attaching a 14 gauge metal wire from the base
to the ball.
It sounds as if both methods would only make one sprue wire
(path for the silver to get the the model). i have found that one
wire is just not enoung path way to get a half ounce or more of
metal forced through it in the small amount of time necessary.
Remember, every casting method used for silver and gold casting
(not as important in pewter casting) depends on forcing the metal
into the mold quick enough to prevent the surface area of the
mold (investment} from freezing the metal before it fill the
mold. I found that one sprue did not work.
The metal wire sounds like a good idea (it would hold the wax
pattern more firmly than wax), but remember that you must depend
on “surface tension” to keep the metal up in the sprue button and
out of the sprue wires until the steam is applied. Thus forcing
the metal down through these small 14 guage sprues wires, in to
the 8 or 10 guage sprue wire and then into the mold made by the
wax pattern. I believe that the simple pulling out of this metal
wire would also pull or break out some of the investment at the
surface of the sprue button (which becomes the crucible). This
allows the molten metal to enter the sprue wire and freeze before
the steam can be applied. I would not want to take the chance of
preparing a wax pattern, spruing it, investing it, and burning it
out only to have it fail because of this problem that is easy to
avoid with wax wires.
I really do not understand the wax ball thing! It sounds as if
the author could only figure that method to get the wax to stick
to the metal wire.
I really appreciate the I would like everyone that
has read, heard, or tried any method different from mine to
please let me know of those differences. I want this Steam
Casting Online Class to be the best, most detailed, mistake proof
class (article) that will ever be written on this subject.
I promise I will pass along all methods and include them in the
"Online Class". I will also try each method if I think they could
be better than what I am teaching. These two methods just do not
have enough merit for me to try. If any one has used them or
would like to try, I would love to hear from you.
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