I’ve been molding with RTV stuff, and due to lack of rigidity and
poor wear factors, wish to switch to vulcanizing to make molds. Does
anyone have another room temperature solution that’s as good as
vulcanized materials, and DOES ANYONE HAVE A VULCANIZER THEY’D LIKE
TO SELL?
I’m in London Ontario, and I’d drive 300km/200mi. Shipping is an
option to if you know how 
Joris Van Daele
Joris, for years I used the Dow corning Silastic RTV with great
results. The E (green in color) is more rigid and has a very high
tear strength. Very similar to the vulcanized silicone rubber that
Contenti sells. The other Dow Silastic product is the L which is much
softer and has a lower tear strength. Either of the products is
great, I have molds that are 30 years old and still just like new. No
hardening or crumbling of the rubber. Dow use to sell one pound cans
of the stuff but I haven’t shopped it lately. I did a search on Dow
Silastic and got a web site for them, the draw back was that it was
all packaged in 4 to 20kg tubs. Makes it a fair cash layout for a
product with a fairly short (6months or 1 year) shelf life. You might
check further and see if you can still find the 1lb cans or maybe
just 1kg. I usually get about 3 to 5 molds from a 1lb can. There are
other products and dealers out their and they will usually help you
find the RTV to suit your needs. I always ask them how it compares in
hardness and tear strength to the Dow Products as a reference. Good
luck with your search and let us know what you find.
Frank Goss
Did a little more research myself and the E Dow Silastic is
available in 1lb cans. Here is the link to the site and page
hope this helps. Cost makes it a little expensive compared to
vulcanized rubber but for a mold that lasts 30+ years I think its is
not bad. Figure 3 to 5 molds per.5kilo and you get $13 to $8 per
mold. Thousands of waxes and the cost is just pennies per wax with a
mold that has a shelf life of (haven’t lived long enough to find that
out). Luck
Frank Goss
I do have a cheap suggestion for you… Years ago before the
Dinosaurs I had no money for many tools… I took a mold frame and 2
sheets of 1/4 inch thick alum. drilled 2 holes on each side where the
sheets overlapped the mold frames and then simply bolted the sheets
over the mold frame… put it in my toaster oven for 1 hour at 315
degrees and was in the mold making business… had great results…
Just takes a little more time to set it up… but will get you through
until you can find a vulcanizer.
Vernon Wilson
Joris,
No way are you getting my vulcanizer, besides the thing weighs a ton.
Long ago I used a toaster oven (not for food use anymore) and a
couple of 1/4" Al plates. I got fancy and drilled holes so that
every thing could be bolted together but the basic instructions using
C clamps were included with most castilado boxes of rubber. Probably
not good for the clamps but it sure worked fine. Not room temp but
if you have a studio as cold as mine every bit of heat helps.
jeffD
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand
Hello Jeff, I wrote those instructions that Castaldo sent out. It
was a reprint of an article I wrote for one of the monthly magazines.
I was flattered and still am that castaldo would notice my article.
after several hundred molds made that way, I finally swapped a
friend my small rollers for a vulcanizer. The method of using “c"
clamps and 1/4” aluminu m plates works fine. 8 minutes for each sheet
of Castaldo gold at 275 degrees in the kitchen oven and its done. As
long as your partner has a sense of humor about the kitchen oven.
Have fun.
Tom Arnold
Dear All,
Tom Arnold’s article in the now-defunct Rock & Gem magazine is on
our website at:
http://www.ganoksin.com/gnkurl/1fg
Be sure to check the temperatrue with a good thermometer.
Michael Knight
Castaldo
Tom Arnold's article in the now-defunct Rock& Gem magazine is on our website
Rock & Gem is still publishing. I got the latest issue two days ago.
Al Balmer
Pine City, NY
I found one of these in the alley of a commercial rental of mine
after a jeweler tenant vacated It’s a Rey brand with dual
temperature controls, 120 V, seems to heat up and work fine. I’d love
to trade for a rolling mill if anyone is interested.
Daniel
Tom,
As long as your partner has a sense of humor about the kitchen oven.
I no longer have a partner but if I tried such a stunt I’d have made
into dog feed. Not a food oven period.
jeffD
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand
I have an older vulcanizer if you still need one
[diane at meltingpointjewelers dot com]
Diane
716-856-7599
Try Castaldo LiquaCast Long Life RTV.
Michael