You got me Steaming!

Hi Elaine, I have heard that you can use a potato to steam cast
with. Is it true that only certified organic potatoes work best?
If so, does Gesswein plan to market these with their trademark
affixed. Maybe you could get Dan Quayle to do some promo for you.
J.A. (see you at the N.Y. EXPO)

J.A. Henkel: A personal thanks for the idea to use arrowroot
powder instead of talcum when separating molds. Only had two
failures, before I had 10 to 15 out of 25 tries. Since I’m from
Idaho I can supply the potatoes to Elaine. Shipping by railcar
can be a long process and expensive (tehe) Ron


Just happened to see your thank you posting concerning the use
of arrowroot powder instead of talcum. Could you please tell me
how this works better? Like you, I have a rather high failure
rate with my waxes and would sure appreciate some help here.

Thanks in advance;

Hi Steve: I really wish I could tell you why it works better but
it does. One thing that J.A. Henkel told the orchid forum about
a year ago is No. 1 arrowroot powder is much healthier for you
to breathe than talcum powder. Talcum powder is really dangerous
to your lungs because it is a heavy mineral. Arrowroot powder
is a vegatable, therefore much better for you to breathe. It is
much slicker than talcum so the wax seems to flow into the rubber
cavity and fills it much much better than talcum powder. I went
to Fred Myers health food department and bought a pound for about
$5.00 which will last me 3 or 4 years and I would never go back
to talcum or for that matter the spray junk they sell at most
jewelry supply stores. I can assure you that you will not be
disappointed using it once you buy some and use it. I just put a
little bit in a 6 in square cloth and tie it, then just touch it
to the mold and then inject the wax. Ron Visit us at Steve & Carol Klepinger wrote:


Very interesting! I never heard of using arrowroot powder but I
sure will try it. Like you I suspect, I’ve had the darndest times
getting a mold to completely fill and cranking up the pressure in
my injector until it blew out the other end “OUCH!” Needless to
say, I appreciate your info.

Best wishes and interesting times;

 One thing that J.A. Henkel told the orchid forum about a year
ago is No. 1   arrowroot powder is much healthier for you to
breathe than talcum powder. 

Just curious, and I’m not a caster by trade, although, I will
confess to having cast at one time…but would Cornstarch work as
a release agent? Seems as though it is of a finer texture than
either Talcum, or Arrowroot. Easier to obtain than the latter,
and still a vegetable product. Just thinking too much as usual.
If anyone decides to give it a try, let me know how and if it

Lisa,(Am sick of hauling wood for the woodstove…we still have cold nights here in
(Hah!) sunny southern California), Topanga, CA USA

Yes, Lisa, cornstarch works wonderfully. I have used it for
years, it is very slippery, and very inexpensive. Curtis

Dear Steve, I met John Henkel at last years MJSA show in
Providence. He told me that arrowroot is safer to ingest than
Talcum powder. I guess we all can’t help breathing some of
those little clouds that are made when a mold is “talc-ed”. ( I
presume to reply for Mr. Henkel as I just saw him in this year’s
MJSA show in N.Y. and he may not have access to his e-mail for a
couple of days— I thought I’d pass it along.

Steve, you may also need to be cutting your molds slightly
differently. Specifically, you need to cut a mold so that air can
get out of all areas. Wax won’t force in against back pressure
in a trapped recess. Many recesses need some sort of relief cut.
One of the big functions of powdering a mold is that the powder
gets in these release/air escape cuts, and keeps them from
sealing so tightly that air cannot get out. The air trapped in
the mold escapes around the powder particles. Often, the second
"shot" into a newly powdered mold is better. The first injection
clears excess powder from the mold cavity itself, where as often
as not, with modern waxes (which already have release agents in
them and don’t stick much to the molds), it’s not really needed
and only gives you a rougher wax model. But that first injection
leaves the traces of powder in the release cuts of the mold,
allowing air to escape as the mold is filling. Areas that
consistantly don’t fill often just need another, or a deeper
release cut.

Peter Rowe

I’ve seen a lot of comments on talcum powder but no one seems to
have mentioned why it is dangerous to breathe. The majority of
talc has some asbestos fibers in it. They occur naturally in the
rock environment it is found in. There are asbestos free
soapstones for carving that I have seen for sale in Montana, but
I am under the impression that this is an exception. R.A.
McArthur @O_B_McArthurs


What do you think of the newer silicon molds? I’m refering to
the cold mold, 2-part kind. I really like the ability to make
molds of organic items as well as from the origional waxes and
the quick-release feature but I have a little trouble with air
bubbles. Even when I use a friend’s vacum table, I still get too
darn many bubbles for my liking. I haven’t seen any posts on it.
Any info available there?


Asbestos and silica are two well known problem agents but any
mineral dust is bad to breathe. Because these dusts are not
organic they do not get carried away easily if at all by your
system and tend to remain in your lungs for a long long time .


James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601


Thanks for your advise. I’ve just begun using this product and
I must say that it’s messiness and problems with bubbles makes it
almost too much trouble. I’ve vacumed this stuff until the cows
came home and it’s still full of 'em! I just heard of the new
Castaldo product “Quick-Sil” that uses no fussy mixing,
de-bubbleizing and cures as fast as 15 min.! Not tried it yet but
I already think I’m gonna like it.



I just heard of this new product from a fellow jeweler today!
According to the flyer I have, it cures in 15 minutes! No
bubbles, no vulcanizing, no precise measuring/weighing,
self-lubricating. Sounds too good to be true. I wonder what
it’s shelf life is. I’m especially fond of silicone mold
compounds because they are cold and I can make molds of anything
however, I always had trouble with bubbles. Thanks very much for
your thoughtfulness in relaying the info. I’m sure going to try
it out and look forward to hearing what others think of it.


Dear Peter & all,

If you like and recommend silicone RTV compounds such as Dow

Corning’s Silastic, you’ll love our new CASTALDO LiquaCast RTV 0%
shrinkage liquid rubber.

Unlike the older silicone compounds, it's easy to mix, easy to

de-bubble and makes long-lasting PRODUCTION molds that are
strong and tough.

And the price is a fraction of what you've been used to paying. 

I'd be happy to send you (and anyone else interested) a free

sample kit if you’ll give me your shipping address.

	Michael Knight

	F. E. Knight Inc.

F.E. Knight, Inc., 120 Constitution Blvd., Franklin, MA 02038 |
508/520-1666 |

I’d agree, the new quick-sil looks very interesting. However,
it still requires the pressure of a vulcanizing press to force
the curing rubber around the model. That may limit it’s uses with
more fragile models, such as many wax models, for example.

The liquid silastic rubbers are a pain to work with, but once
you get the hang of it, and learn how to vacuum the stuff
correctly, it DOES work very well. Note that vacuuming these
materials is a wildly different process than that used with
investments or plasters etc. which will simply boil once and be
debubbleized. You’re not vacuuming till the cows come home.
You’re bringing them only as far as the gate, then sending them
back to the pasture. And then calling them in, again, only as
far as the gate. Repeat till the cows are really tired… And
then do it again after pouring the result into your mold. total
time under the vacuum is going to be about 12-15 minutes, and
you’re going to be nursing it the whole time… A pain when
you’re doing only one. But if you’re doing a dozen molds at a
time, it’s OK. By contrast, if you’ve got the new putty types of
silicone, but only one vulcanizer or other suitable pressing

Peter Rowe


The cows say they think they would love the new 2-pt. silicone
product. You make an interesting point however, concerning more
fragile models but the previous product is not exactly water-thin
eather. Also, I understand that it cures in about 15 min. and
you can even use a heavy book to clamp the mold, no need for a
vulcanizer. If you’re making just one or two molds and are in
something of a hurry( and is’nt everyone?) it should be much more
convenient. I confess that I’ve not tried it yet but on the
surface, this sounds like a definate improvement.

Best Wishes;

P.S. I enjoyed your improvement on my metaphor!:slight_smile:

Dear Peter,

Yes, the new Quick-Sil is okay only for relatively strong

models that can take some pressure.

But you are mistaken about the difficulty of using new

LiquaCast liquid RTV. To beginning with, you don’t vacuum until
all the bubbles are out and the cows come home. Unlike
traditional silicone rubbers, it will never stop bubbling. Just
vacuum for 5 minutes before pouring and and another 5 minutes in
the mold frame.

If that's too long, there are two  tricks from the old days

that is also useful for people who don’t have a vacuum pump.

the first is to paint the model with a an artist's brush dipped

in the rubber – working time is 45 to 50 minutes, so that’s not
a problem. Examine the painted model under a loop for bubbles and
use a pin to burst any you find. End of process.

Or dip the model upside down in a container of the liquid

rubber, let it drip off a bit and then use the process outlined
above. It works and its cheap & easy.

My offer of free samples to you and anyone else who gives me

their shipping address still stands.

		Michael Knight

F.E. Knight, Inc., 120 Constitution Blvd., Franklin, MA 02038 |
508/520-1666 |

Michael, I hate to cut molds, and I understand Castaldo has a
new mold material that doesn’t need a vulcanizer. If this is
true could you send me a test kit? My mailing address is P.O.
Box 2334, Flagstaff AZ 86003-2334.
I would really appreciate it. Thanks a bunch! Nina

I was discussing my method of vacuuming the Dow Silastic E, not
implying that the LiquaCast product might require the same.
The Silastic product never stops bubbling either, and never
appears, during the vacuming stage, to have all the bubbles out.
It just keeps expanding till it wants to overflow… That’s why
my joking reference to the cows had em going back out the the
pasture when just at the gate (grin). This is why it’s necesary
to pull the vac til it almost overflows, collapse it again by
letting air in, and repeat over and over until one has spent that
5-7 minutes doing this. This isn’t really all that difficult,
and once figured out, is easily done. The only dificulty is
that it’s quite different from how one vacuums investment, so if
one is expecting the same procedure, it will be a mess.

If the liquaCast is easier to vacuum, that would be great! I
vacuum the silastic initially for more like 7 minutes, but all in
all, your times appear similar for the liquacast as i use for the
silastic. Does the liquacast also try to overflow the container
it’s vacuumed it? Or is it a bit less viscous and more workable?

The pouring process of the traditional silastics are ok, and not
really a bother. More of an issue in evaluating your new rubber
would be the characteristics of the final mold. how does it
compare for tear strength? how about long term durability?
Silastic E molds seem to start getting weaker and less flexible
after a time. At least, my 15 year old ones are pretty much
useless now.

Also, what about pricing? how much does the liquacast rubber
cost, both in small quantities and larger ones? What’s the shelf
life of the uncured rubber?

Peter Rowe