I have always struggled holding 4 and 5 inch flasks with the typical
tongs throughout the casting cycle. This weekend I placed a model in
a 6 inch flask. The problem was how to hold it when removing it from
the burn out oven and then hold it while quenching it.
My solution worked well for me. I removed a small amount of
investment from the edge of the flask on both ends after the
investment set. I placed the large flasks near the front edge of the
burn out oven. After burn out I used a large pair of vice grip
pliers to grab the edge of the flask that was uncovered by the
removed investment and lift it out of the oven and place it on its
side on the vacuum table. I removed the vice grips from the non sprue
end and gripped the sprue end of the flask and placed it on the pad.
Once the metal was poured I lifted the flask by the vice grips and
set it aside to cool. I held the flask with the vice grips while I
quenched it.
The flask was held very securely by the vice grips throughout the
casting process.
Interesting solution. I wonder if it might be possible to weld a
“fin” on the outside of the flask, say 5/8" by 2" or 3" long and 1/4"
thick. This would make grasping with the vise grips or a large set of
tongs possible. The fins would not interfer with the flask placement
in the oven. If they are made of stainless steel there should not be
an oxidation problem either. I can’t see where there may be an effect
of the heat transfer to or from the flask.
This might just be a new invention! Y’all saw it here first.
The fin would help get your hands further from the flask and away
from the ends at quenching.
Just an idea. I have to deal with large flasks occasional too.
Lee, I would like to see photos of this method. I, too, have a hard
time holding flasks and moving them around for centrifugal casting.
This sounds like it could work for me, but I can’t picture it (that’s
another issue).
I was involved for a few years in developing a large vacum casting
system for a sculptural foundry and I developed a system for getting
flasks in and out of a top loading kiln. To give you some idea we
were using flasks up to 20" high and 10" across, some used 3-4 bags
of plaster each.
To lift in and out I drilled a pair of 1/4" holes 1" in from each
end across the widest section, ie a diameter. Then cut a piece of
1/4" stainless steel studding 2" longer than the diameter and bolt in
place inside and out, this is the bottom of the flask. The other end
use 1 1/4" ss bolts with the heads on the inside. To lift you make a
strong wire loop like a bucket handle only with the little loops at
the end twisted to go sideways I still use a bucket handle for one
size of flask!).
You can drop the flask over your wax model quite easily, and the
studding supports the plaster at the open end. There is obviously a
lot more to it than this, the foundry went on to LARGE perforated
flasks but I still use my system to great effect.
Would a big oil-filter wrench, or vise-grips that use a piece of
bike-chain be good tools for this purpose. All metal surfaces and
used gently all the way thru the casting progress, of course.