Burnout kilns - Casting shell

Hi to NZ. I am a longtime caster and can assure you that shell will
not burn out successfully. If it’s just a one-time thing, butter up
your dentist - or barter with one - and have him/her make a temporary
mold of it for you with the same stuff they mold teeth with. Most
dentists love to cast and have the equipment for it. See what you
can do. Otherwise, the jewelry catalogs have the soft, putty like
mold material. You’d make that up and then fill the mold with melted
wax and cast that. It will give you very good results and you’ll
still have the shell in case every friend wants one later.

Pat

Hi Pat, Got to disagree with you…I have burned out shells many
times and have never had a problem. My technique is to allow the
final maximum temperature bath to be extended for an hour or two and
I usually jack up the temperature to fourteen or fifteen hundred
degrees fahrenheit. Ain’t no problem mon! Ron at Mills Gem, Los Osos,
Ca.

  1. coat shell with a very thin layer of plastic or epoxy
    1. dissolve shell away with sulfuric/hydrocloric acid
    2. fill hollow plastic film with wax
    3. sprue and cast as usual

Mark Zirinsky
Denver

I’m with Ron on this one. I have cast rattlesnake vertebra, bird’s
skulls & even chicken bones. When casting these types of material I
soak the bones in molten wax for a while to try to get a bit of
saturation to aid in their removal. I then wipe off the excess with
cheesecloth.

I found that a larger than normal sprue helps in the elimination of
ash. The chicken bones were too heavy to sprue with wax- I couldn’t
get enough adhesion and they kept floating to the top of the flask.
I drilled a hole in the bone & 5 min. epoxied a small wooden dowel
in place. I had to hold the flask @ 1350 for over 24 hours &
occaisionally blew the mold cavity out with compressed air (wear a
face shield.)