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Casting fractures


#1

When I cast sterling silver wire or long flat ingots in a typical
steel bookend mold, the top 1/4" almost always fractures off after
the first couple passes through a mill. I do an initial anneal and
anneal often, but this seems to always happen. I build it into my
plan, but it is curious. Any thoughts would be appreciated. Rob

Rob Meixner


#2
When I cast sterling silver wire or long flat ingots in a typical
steel bookend mold, the top 1/4" almost always fractures off after
the first couple passes through a mill. I do an initial anneal and
anneal often, but this seems to always happen. I build it into my
plan, but it is curious.

Use Delft clay for making ingots, the grain structure is more
consistent, and you don’t have to pre-heat the mould. Pour fast. CIA


#3
When I cast sterling silver wire or long flat ingots in a typical
steel bookend mold, the top 1/4" almost always fractures off after
the first couple passes through a mill. I do an initial anneal and
anneal often, but this seems to always happen. I build it into my
plan, but it is curious. Any thoughts would be appreciated. 

Chop off the last 1/4" after it fractures and put that bit in your
next melt.

Paf Dvorak


#4

i carbonize my mold as well as preheat it. do not over tighten the
clamp tighten in just enough that the clamp stays in place under
fill the mold by a few mm and record how much you need to make that
point

if using old material always add a bit of new

never try to open pour more than 60 gm unless you have an electric
crucible

if you are using gas and an open crucible dont be afraid to use a
bit of borax

if you over fill the mold shrinkage between the larger opening and
the consistent mold form will always give you fracking (excuse the
sum of words)

i seldom have issues but still do from time to time i think you need
to hold your tung in your teeth stand on one leg and recite Juliet’s
monologue as well.

romeo romeo

Les


#5
never try to open pour more than 60 gm unless you have an electric
crucible 

I can do up to 1.5 kg of copper alloys at the moment (and the
equivalent volume of other metals), I use a gas furnace.

For smaller melts using precious metals, I use a 250 gram crucible.

I have to pour quicker with smaller volumes (obviously).

Regards Charles A.