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Crucibles


#1

Someone once posted that they got a new crucible in their casting machine
and their porosity problems went away. Someone else also posted that if you
heated up your crucible and it didn’t turn evenly red then oxygen was
getting in. How DO you tell if your crucible is ready to be tossed out?
I’ve read you can clean them out by boiling in a dilute sulphuric acid
solution, would this work just in your pickle pot? Also, I bought a used
casting machine and got some pretty cruddy old crucibles that went with it
and thinking about getting a new crucible, so how do you break the thing
in, i.e. put a nice even coat of flux on the sufarce. Do you heat the
crucible first then toss some flux in or the other way around. …Dave

Art Jewelry for Conscious People
http://www.opendoor.com/stephensdesign/crystalguy.html


#2

Dave, I think you’ll find that contaminated crucibles are a major
problem in poor castings. Definitely start with all new crucibles! Use
a different crucible for each metal type (ie. 14ky, 18ky, etc.) Never,
but never, use the same crucible for palladium WG and Nickel WG! When
seasoning the crucible, heat it to a dull red then evenly spread flux
over the top, continue heating, etc. When the glaze is complete it will
be beautifully glassy. When casting, it’s important to keep your flame
centered over the metal and NEVER remove it! This deprives O2 from
getting into the melt. You can add flux with a carbon rod through the
flame. Also, use a “reducing” flame(less 02 than normal in your gas/oxy
mix). Good Luck, Mike


#3

Dave, I think you’ll find that contaminated crucibles are a major
problem in poor castings. Definitely start with all new crucibles! Use
a different crucible for each metal type (ie. 14ky, 18ky, etc.) Never,
but never, use the same crucible for palladium WG and Nickel WG! When
seasoning the crucible, heat it to a dull red then evenly spread flux
over the top, continue heating, etc. When the glaze is complete it will
be beautifully glassy. When casting, it’s important to keep your flame
centered over the metal and NEVER remove it! This deprives O2 from
getting into the melt. You can add flux with a carbon rod through the
flame. Also, use a “reducing” flame(less 02 than normal in your gas/oxy
mix). Good Luck, Mike

Mike: thanks for the reply, just what I needed to know. My first experience
with a crucible was a sandcasting kit with terrible instructions. I had a
LIttle Torch with a melting tip , barely knew how to solder at the time. I
was throwing borax in the crucible and heating and it wouldn’t stick. Did
this in my little condo at the time. Looked around after awhile and the
whole place was filled with borax smoke! I felt sick all the next day.
Needless to say I didn’t try anything after that! Will order a new crucible
or two tomorrow, thanks…Dave

Art Jewelry for Conscious People
http://www.opendoor.com/stephensdesign/crystalguy.html


#4

In a message dated 96-11-19 11:21:11 EST, you write:

Dave, I think you’ll find that contaminated crucibles are a major
problem in poor castings. Definitely start with all new crucibles! Use
a different crucible for each metal type (ie. 14ky, 18ky, etc.) Never,
but never, use the same crucible for palladium WG and Nickel WG! When
seasoning the crucible, heat it to a dull red then evenly spread flux
over the top, continue heating, etc. When the glaze is complete it will
be beautifully glassy. When casting, it’s important to keep your flame
centered over the metal and NEVER remove it! This deprives O2 from
getting into the melt. You can add flux with a carbon rod through the
flame. Also, use a “reducing” flame(less 02 than normal in your gas/oxy
mix). Good Luck, Mike

I have been reading this discussion with interest. I recently purchased a
couple of melting dishes/crucibles (are the terms interchangeable?). These
require long-handled tongs. I purchased them in order to try to melt silver
to do “water casting”, according to an article in the Jewelry Journal section
of Lapidary Journal. (It looks easy enough for me to try!)

Until Dave’s question popped up about crucibles, I had no clue that they
needed seasoning. Mine are of a porous, ceramic type material. Am I correct
in assuming they, too, need seasoning? And does it matter what kind of flux
is use to season them with.

Any info on water casting, melting silver and related topics eagerly
accepted.

Thanks,
Candy Glaze


#5

Candy - Yes, you need to season your crucible as well. As far as I
know, any type of powder flux is fine. I use straight ol’ borax with
lovely results. As far as water casting goes, I assume you are just
melting and pouring, and no, no special requirements. Just melt with a
reducing flame, keep the flame over the metal to deprive oxygen and pour
into a bucket. You may wish to line the bottom of the bucket with
copper if you use a plastic one as I do. If not, you’ll surely swear
like a jeweler as you pry those chunks from the bottom. Torch on, Mike


#6

I have been reading this discussion with interest. I recently purchased a
couple of melting dishes/crucibles (are the terms interchangeable?). These
require long-handled tongs. I purchased them in order to try to melt silver
to do “water casting”, according to an article in the Jewelry Journal section
of Lapidary Journal. (It looks easy enough for me to try!)

Until Dave’s question popped up about crucibles, I had no clue that they
needed seasoning. Mine are of a porous, ceramic type material. Am I correct
in assuming they, too, need seasoning? And does it matter what kind of flux
is use to season them with.

Any info on water casting, melting silver and related topics eagerly
accepted.

                >Thanks,

Candy Glaze

Borax would probably do you just fine. Go to your local grocery store and
get the 20 mule team stuff, seriously thats what people use. For casting I
use casting flux but for your use the laundry borax is just fine…Dave

Art Jewelry for Conscious People
http://www.opendoor.com/stephensdesign/crystalguy.html