Back to Ganoksin | FAQ | Contact

Temperature at the time of casting


#1

Okay here it is I am copying this from a good text on jewelry making and
have these temperatures to be correct…White Gold should be cast when
the flask is 1000-1075 degrees F…Yellow Gold should be cast when the
flask temperature is 900-975 degrees F…Silver should be cast when the
flask temperature is 800-850 degrees F…Bronze is cast at 900 degrees
F…Gavin


#2

So much for the silicon pads! …at those temps for gold anyway

At 10:53 AM 10/4/96 -0500, you wrote:


#3

I cast bronze in perforated flasks in a vacuum well chamber. Flask temperatures
are at 900 to 1000F, depending on the casting design. I’ve been using the same
silicone gaskets for years; the trick is to use a paper gasket interface between
the hot flask and rubber gasket. The paper gasket in smeared heavily with
hi-temp grease before it is placed. Considerable smoke is generated when the
flask is placed in the well but I have an exhaust fan located at the pouring
station so this isn’t a problem for me.
Winston W. Harness
http://ourworld.compuserve.com/homepages/brnzcaster/On Fri, 04 Oct 1996, Jim Chambers pega@digital.net wrote:

So much for the silicon pads! …at those temps for gold anyway


#4

Winston,
That I’m going to do!.. was this a result of burning the silicon pads???
BY Machine instructions say… 900 degrees … and I burned the very first
one… Company agreed that the pad would ring at that temp

Jim
At 05:08 PM 10/4/96 -0700, you wrote:

I cast bronze in perforated flasks in a vacuum well chamber. Flask
temperatures
are at 900 to 1000F, depending on the casting design. I’ve been using the same
silicone gaskets for years; the trick is to use a paper gasket interface
between


#5

The silicone pads will start to char at around 800F. The grease placed on the
gaskets will seal any minor cracks and irregularities long enough for the pour
… my vacuum draw on the flask (a 5x7 inch) will typically be 20+ inches with
this setup.
Winston W. Harness
http://ourworld.compuserve.com/homepages/brnzcaster/

Winston,
That I’m going to do!.. was this a result of burning the silicon pads???
BY Machine instructions say… 900 degrees … and I burned the very first
one… Company agreed that the pad would ring at that temp
Jim


#6

Basically I believe I have been doing things correctly per the forum
advise… paper and the grease I’ve never tried… NEXT TIME! Like the idea
it provides of the temp problem, as well as sealing … my pours with lets
say a TREE of 8/10 items only produces about 4/5 items… for that reason I
have been trying a method suggested by a local production caster… NO
TREEs,… using a DOMED CENTER RUBBER POURING CAP(Best description I can
think of … what the h … is the proper name anyway!??) spur with 1/8 wax
stems all over the dome(like porcupine quails) … This, with a relatively
large cylinder( 4 inch??) provide about 20/25 items with NO … I said NO
parti cal casting(Like… 98% return!.. ‘Ain’t All Bad!!! . . Dude’

What Say You… Ever heard of the method before… Think he invented it???

Jim
At 02:29 AM 10/5/96 -0700, you wrote:


#7

“Sprue Base” is the word you’re looking for.
When using a 5x7 inch flask, I sprue off a 3/8" center rod of beeswax and gate
maybe 60 injections off this rod … yield is 100%. Ya gotta have your melt at
the proper temperature for complete runs.
Very little re lostwax casting has been “invented” lately … this is 6000 year
old technology. Common sense and notes of what you’ve done before is the secret
to success.
Winston W. Harness
http://ourworld.compuserve.com/homepages/brnzcaster/

Basically I believe I have been doing things correctly per the forum
advise… paper and the grease I’ve never tried… NEXT TIME! Like the idea
it provides of the temp problem, as well as sealing … my pours with lets
say a TREE of 8/10 items only produces about 4/5 items… for that reason I
have been trying a method suggested by a local production caster… NO
TREEs,… using a DOMED CENTER RUBBER POURING CAP(Best description I can
think of … what the h … is the proper name anyway!??) spur with 1/8 wax
stems all over the dome(like porcupine quails) … This, with a relatively
large cylinder( 4 inch??) provide about 20/25 items with NO … I said NO
parti cal casting(Like… 98% return!.. ‘Ain’t All Bad!!! . . Dude’

What Say You… Ever heard of the method before… Think he invented it???

Jim