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Oven vulcanization


#1

Hello,

Is it possible to make vulcanized molds in a toaster oven( with
C-clamps) instead of a vulcanizer? I have heard of this being done
but I thought I would ask the experts whether it was possible and if
so, the process. Thank you Steve


#2

Steve, I was going to let one of the more experienced folks on the
list respond to your query, but when I didn’t see a quick answer
thought I would share. I have not used this method of vulcanizing
rubber, however I just completed reading the chapter on casting in
The Complete Metalsmth, by Tim McCreight. It mentions how you can
make rubber molds in your kitchen oven. I am not sure if a toaster
oven has enough space or would keep the temperature consistent. Yes,
you would use a C-clamp, and you would need either a pre fab aluminum
mold frame or to make your own. The chapter has pretty clear
instructions on temperature and frequency for tightening the clamp
down as well as over all length of time.

I hope this helps.
-Karine


#3

Not a toaster oven I dont’ think, but a real oven. A friend of mine
does this with great success. I tried it, but the molds weren’t
good enough. Perhaps I didn’t get enough pressure. The results of
my experiment: now I happily pay the caster.

Elaine Luther
Chicago area, Illinois, USA
Certified PMC Instructor
@E_Luther


#4

Hi Steve, YES, it is possible to make vulcanized rubber molds in a
toaster oven. I have done it several times and have taught it within
the context of a lost wax casting class at our local technical
school. First, I heated the toaster oven and checked the accuracy of
the temperature with an oven thermometer. Then, mark the correct
temp on the dial of the toaster oven. Make sure you have your mold
well filled so that pressure is applied to the rubber layers when you
tighten those C clamps. And, don’t be afraid to re-tighten during
the process. You’ll need to be especially careful to leave the mold
in for the adequate amount of time. Also be careful when inserting and
removing the unit from the oven…don’t want you to get burned or
electrocuted! I have also done this same process using my kitchen
oven. If you need more details, let me know and I’ll try and locate
the handout that I prepared for my class…

Alice - in Wisconsin where blue skies and sunshine are camouflaging
bitterly cold temps.


#5

I have made rubber molds with c clamps and a toaster oven. You still
need an aluminum mold frame, and I would not bother with the toaster
oven. I just use my gas range at home. It only has to be heated to
325 degrees. Get a good oven thermometer and adjust the temperature
according to it, not what it says on the oven controls. Rio Grande
sells a mold clamp that is nothing more than 2 heavy aluminum plates
with a pair of bolts through them. I having been using it for years,
works great.


#6
    Is it possible to make vulcanized molds in a toaster oven(
with C-clamps) instead of a vulcanizer? I have heard of this being
done but I thought I would ask the experts whether it was possible
and if so, the process. Thank you Steve 

I have made many vulcanized molds in my kitchen oven, never have had
a vulcanizer. If your toaster oven is large enough to accommodate
the clamps and frame, and the temperature is even, I don’t see why it
wouldn’t work.

Lorri
Graham, Washington, USA


#7

Hi Alice I would love to hear how you do a mould in a kitchen oven if
you still have the info.We live on an island and it is such a pain
sending work off island,it takes so long.

Thanks for the toaster oven tip,I dont have one though.
Barbara…from frozen in Nantucket!


#8
           Hi Alice I would love to hear how you do a mould in a
kitchen oven if you still have the info.We live on an island and
it is such a pain sending work off island,it takes so long. >Thanks
for the toaster oven tip,I dont have one though. >Barbara.....from
frozen in Nantucket! 

It’s really not complex, folks. A vulcanizer is merely a device
that combines reasonably accurate temperature control plus pressure.
If you use the same aluminum mold frames you’d use in a vulcanizer
(aluminum, not steel, for good heat conduction), but substitute
heavier aluminum (or in this case, steel) end plates (the sheet metal
plates that cover the top and bottom of the mold frame once packed
with rubber and your model, plus one or two heavy C clamps, you’ve
got the mold under pressure in the same way it would be in a
vulcanizer. Then you pop the whole clamped up frame in whatever oven
you like, be it a toaster oven (if it fits, which I’d doubt), your
kitchen oven, or an enamelling or burnout kiln, if the temperature
controller on it can hold the required fairly low temperature of (for
Castaldo gold lable or white label natural rubbers) 310 to 320
degrees F. If you use your kitchen oven, use an additional oven
thermometer in the oven, rather than just trusting the oven
settings. The pressure needed is simply whoever much you can
tighten the C clamps. the temp is as above, and you leave it in the
oven for seven minutes per 1/8 inch thickness of rubber used. If you
forget this, the temperature setting and time is conveniently printed
on the liner paper that comes on the rubber. about the only real
change between this and how you’d do it in a vulcanizer is that the
plates have to be heavy enough so they stay flat and compress
properly when you clamp them with just C clamps, whereas with a
vulcanizer, you can use thing aluminum sheet metal just fine. One
note, though. If you use your kitchen oven a lot for food, you might
want to think twice about doing lots of molds in it too. Not that
it’s toxic or anything, it isn’t. But your oven might end up with a
slight bit of the sulpher/rubber smell from the molds, and I’m not
sure how that would affect your meals… (grin). With burnout or
enameling kilns, you’ll likely have trouble holding such a lot
temperature, so you might need some sort of thermostatic control
beyond what the oven comes with, or a digital controller, or the
like…

Peter


#9

Dear Barbara, We have an extensive article on exactly that – how to
use a toaster oven to vulcanize molds – on our web site at:

http://www.castaldo.com/english/usinprod/athome.html 

Michael Knight
CASTALDO


#10

I don’t care for the C-clamp method, personally, as you often will
get bubbles in the molds because the pressure doesn’t stay
consistent. What I’ve found works really well in this instance are
the large plier-shaped clamps that can be found at your local home
improvement store. Get a couple of nice firm ones and strip the
plastic off the handles. Use them instead of the C-clamps and you’ll
get a lot better results.

Talia


#11

Hi Folks, I’m feeling guilty here…didn’t want you to think that I
had not answered Barbara’s question. (I had an unusually hectic
Monday & Tuesday at my “day” job and shot off a short note directly
to her, explaining that I’d sent complete info today.)

Part of the beauty of Orchid is having sooooo many knowledgeable
people willing to share. Thanks to Peter Rowe and Michael Castaldo
for typing an answer so quickly!!!

Alice - in Wisconsin under heavenly blue skies &, (finally), a
dusting of the white stuff, too!


#12

Hi Talia,

    I don't care for the C-clamp method, personally, as you often
will get bubbles in the molds because the pressure doesn't stay
consistent. 

Couldn’t tell you why, but, I haven’t had any trouble with this.

What I've found works really well in this instance are the large
plier-shaped clamps that can be found at your local home
improvement store. Get a couple of nice firm ones and strip the
plastic off the handles. 

This is a great idea especially for the folks who intend to use a
toaster oven. The C-clamps really tend to get in the way and
complicate getting the mold frames in and out of the oven.

Alice - in Wisconsin where the skies are gloomy and threatening.