DIYbanter - View Single Post

wrote:

Casting in a metal mould result in a welded piece of work using 925
grade silver. Lol.

I don't see why "casting in a metal mould (would) result in a welded
piece of work"

lead and zinc and alluminium are all cast to my knowledge in metal
molds. I have often cast lead in molds made of brass. Lead is used to
solder copper/brass pipe together, but in the case of the mold I used to
cast civil war era type Mini balls, soldering did not take place. A
mini ball mold is a three part mold, a two part hinged outer mold and a
base pin to make the hollow part on the base of the bullet. The reason
the mold is not "soldered" together is that a "release compound" is
employed. The most common way to insure that the metal mold releases
the casting, is to 'smoke' the mold. This is done with a candle flame
held to the casting to deposit soot onto the mold, this in turn becomes
a barrier to the molten metal fuzeing to the mold metal.

It would seem to me that a easy metal mold could be made to cast your
Silver tubes, which if I understand correctly will undergo further work
before the finished object is obtained. Two halves of a copper/brass
pipe slit in half and held together with stainless steel hose clamps
would provide the outer shell and a tapered copper/brass rod could
provide the inner core. A hole could be cut into one of the outer shell
pieces for a pouring hole. Two end caps (copper washers?) with a hole
to accept the core rod would complete the assembly. Smoke all the
surfaces that will come in contact with the molten silver and set in a
bed of sand. After casting, remove the core rod by taping on the end
with a hammer while the cooled mold is set over a wooden bench with a
hole in it that will pass the tapered rod but not the cast tube in the
outer mold. (just make sure you are taping on the SMALL end of the core
tube and if the soot release compound worked as it should, the rod
should pop right out. Now just release the stainless hose clamps and
pry off the two halves of the outer mold. Knock off the end caps with
chisel and behold, a cast silver tube. Maybe I will give it a try with
some lead, the hard part will be to get a uniform tapered copper/brass
rod for the core, but it should be easy for someone to do with a small
lathe. Just an idea, I don't think you would need a centrifugal caster
for this, it could also be done vertically if you could rig up something
to keep the rod centered on the upper end without using a cap washer.