Back to Ganoksin | FAQ | Contact

Steam wax instead of rice?


#1

Hello all:

In the latest edition of Lapidary Journal/Jewelry Artist a read a
suggestion to use an ordinary rice steamer as a flask dewaxer. I do
occaisional, small casting runs and although I’d like to have a steam
dewaxer I haven’t been able to justify buying one. My question is,
has anyone tried this and had good results? I’m a little dubious.

Larry in California


#2

Larry, Some time ago Peter Rowe gave excellent instructions for
using a plain old inexpensive stock pot and a rack as a dewaxer. I
believe he suggested using just enough water to come to the bottome
of the rack–not over it. Placing the flasks, sprue side down, on the
rack and steaming for about 20 minutes.

Would certainly be a lot less expensive than a rice cooker, and you
can always trust Peter’s recommendations.

Alma


#3

I am only a very occasional caster. Wanting to try out Steam
Dewaxing; My answer was to use a large coffee can with a smaller
support can inside (perforated, for steam & wax flow), and a lid of
aluminum foil. Very simple worked very well on a hot plate, cost next
to nothing. Graduated up to a garage sale pressure cooker ($2.00), it
has a wood handle on both the lid & body.

Otherwise the same simple support system inside. Works well & very
cost effective!

Mark Chapman


#4

Ever since I started steam de-waxing (I also could not justify the
expense of a de-waxer!!!) I have used one of those old Hi-Fri deep
fryers (the kind that you can’t GIVE away at a yard sale!) with a
round screen on top (you

can find the perfect round screen in the garden center where
bar-b-que grills are sold, commonly used for bar-b-quing fish)

Water boils & creates steam around 212 degrees.

Put the screen on top, place the flask sprue down, on the screen,
invert a bucket over the flask, boil the water.

Presto-change-o, the result is a de-waxed flask.

You can also choose to recycle the wax after you allow the water &
wax to cool…


#5
Would certainly be a lot less expensive than a rice cooker, and
you can always trust Peter's recommendations. 

Except for when I’m wrong… It DOES happen now and then you know…
I’m just as prone to error as anyone else…

But thanks, Alma, for the compliment. Not sure it’s all that
deserved, but thanks, and I’m glad you find my occasionally too wordy
posts useful.

The message there is to always take ANY advice, no matter where it’s
from, with at least a little bit of caution and common sense. I (or
any other poster) might have had a bad day, might not have been using
the best method even if the one I used had worked for me, or might
just have remembered something wrong. Same as anyone else here.

But in this case, consider:

Commercial steam dewaxers are nothing more than a container with a
door (lid) that encloses the steaming area. No pressure seal or
anything like that. The flasks sit on a rack above a pan filled with
water and an immersed heating element that boils the water. Wax
melts and ends up floating on the water, where it can be picked up as
a grungy sheet-like mass after everything cools again.

Any container in which you can support the flask while enclosed so as
to trap steam, and in which you can generate steam, will work. A big
tin can on the stove, a large surplus cook pot (mine was a buck at a
garage sale), or if you like a rice steamer. But remember, once you
use it for a dewaxer, you’ll not likely ever be able to use it for
much else again. The wax gets everywhere on the thing and is hard to
clean off. A nice rice cooker costs a lot more than an old pot or old
coffee can (as another poster suggested). But it also eliminates the
need to do it on the stove, or presumably in the kitchen.

Your choice. Almost anything you can gerry rig to do this will work.
Try to keep the flask itself out of the boiling water (which might
break down the immersed investment), and have a decent lid on the
whole affair to trap the steam and heat. That’s all you need to do.

Also, understand that steam dewaxing mostly is done to reduce fumes
in burnout. It doesn’t necessarily make a great difference in most
casting unless your burnout oven has trouble completely eliminating
all the wax and carbon residue. Or if you’re doing stone in place
casting, where steam dewaxing is usually required. But otherwise,
many smaller scale casters find it just an extra, and unnecessary
step. In my shop, the only times I do it is with flasks having a lot
of wax in them, so as to reduce smoke and fumes in the shop. Usually,
I don’t bother.

Cheers
Peter Rowe


#6

Have used a cheap Wal Mart rice cooker for steam dewaxing the last
two years. The first unit only last one week and burned out, the
second unit has worked well. Need to put a grate in the bottom of
the pot to keep the flasks out of the water and let the unit do its
thing, checking after a half an hour to see if the wax has melted
out. The bottom of the flask will be clean when done. Steam dewaxing
will not work with carving wax, melting temps of the carving wax are
above the boiling point and will not liquify the wax.

Terry


#7
Water boils & creates steam around 212 degrees. 

The temperature at which water boils varies with altitude and
atmospheric pressure. Assuming a standard barometric pressure of
29.92" those of you at sea level will be boiling water at 212 degrees
F. If you live in Denver at approximately 5000’ you’ll be boiling
water at about 203 degrees F. If you happen to live in Leadville, CO
at a little over 10,000’ you’ll be boiling water at about 192 degrees
F, or if there happens to be a strong low pressure system in your
area it could be as low as 190.

A quick find in google shows melting temps between approximately 141F
and 212F, so at the top end where you live may determine whether an
unpressurized steam dewaxer will work for you or not.

Mike DeBurgh, GJG
Henderson, NV


#8
Also, understand that steam dewaxing [...] doesn't necessarily
make a great difference in most casting unless your burnout oven
has trouble completely eliminating all the wax and carbon residue.
Or if you're doing stone in place casting, where steam dewaxing is
usually required. 

Let me be curious: Why is steam dewaxing required for stone-in-place
casting? Different expansion rates of investment, wax and stone?

Thanks,
Andreas


#9
Let me be curious: Why is steam dewaxing required for
stone-in-place casting? Different expansion rates of investment,
wax and stone? 

with stone in place casting, there is a requirement to not "frost"
the diamonds during the burnout or casting operation. Using steam
dewaxing to remove most of the wax means that with less wax left to
eliminate during the actual burnout, one can get away with using a
lower top burnout temperature, and for a shorter length of time.
With less wax there, you can still get rid of enough of it, even at
the lower temperature, to allow a good casting. Also, with steam
dewaxing, the surfaces of the diamonds which were imbedded in the
wax model tend to come out of steam dewaxing with little wax residue
on them. Remaining wax soaks into the investment if it stays in the
mold (though the steam dewax process also tends to not much allow
that to happen either, since the investment is still soaked in water,
which repels wax. The end result is that during burnout, wax is less
likely to stick to diamond surfaces and carbonize there. Carbonized
wax on the diamonds would increase the risk of damage to the diamond,
so here again, steam dewaxing helps protect the diamonds.

Peter Rowe