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How to mold a teapot leg?


#1

I have a teapot with a missing leg and must cast a duplicate of one
of the legs that’s still attached. Does anyone have suggestions for
the most efficient way to go about molding this? I’m sure there is an
elegant solution to this problem, but my brain hasn’t come up with
it, and my google and Ganoksin search parameters aren’t giving me
what I need. All my molding experience is vulcanized rubber, and my
one experience with an RTV mold involved a mold form that clearly
wouldn’t accommodate an attached teapot leg.

Any help appreciated! Thank you Orchidians!

Jalia M. LaNoue Goldsmith Spinelle Fine Jewelers Napa,
California


#2

Jalia,

I have dealt with the same problem in the past.

My approach is to take a tin can or roll up a cylinder of sheet
aluminum that is large enough to enclose the good leg. I attach it to
the teapot with modeling clay, Jet Set might be good here. Next I use
Rio’s High Temp RTV (701-014), mix it and pour into the can/cylinder.
Once it sets, remove the can. Cut the mold carefully and only enough
to slide it off the leg. Now I can use wire to bind the RTV mold shut
and pour the molten pewter into the mold. It may take several pours
to get a casting you are happy with. The warmer the mold the better
the castings seem to be. Also give them time to cool or the pewter
will still slushy in the center. Now clean and shape the casting to a
perfect fit. The next step is to plate the casting, copper flash,
nickle, then silver. Now to attach the new piece to the pot. I favor
Tix solder with its low melting point, but still above the tempature
of boiling water. I then pen plate the solder seam. I do all of the
soldering with a large bushy flame. Can we say heat control? This is
a lot of work! I charge a minimum of $125/ hour to do it. This is NOT
for the timid as much can and will go wrong in spite of attention and
preparation. It is one 'ell of an ego stroke when you pull it off.

If the piece is Sterling, I would use a regular RTV. Use the
resulting mold to make a wax model, then cast as usual. Remember,
there will be a shrinkage factor with the Sterling.

Hope this helps. I am hoping David Huffman responds this too.

Bill Churlik
@Bill_Churlik
www.earthspeakarts.com


#3

Jalia

I have a teapot with a missing leg and must cast a duplicate of
one of the legs that's still attached. Does anyone have suggestions
for the most efficient way to go about molding this? 

You can use an RTV, as mentioned in your post, but in an
unconventional “frame”. Using a small cardboard box (like the outer
"packer" for a ringbox), mix your RTV, pour into the box, and then
add a leg of the teapot to it. Play with the balance of the teapot on
the box (brace it if needed), and depth needed for the leg, before
you actually mix and pour. After cutting, this will give you a mold
into which you can pour molten wax. Not as effective as injecting,
but will work.

And just for the sake of mentioning it, I like the Castaldo two-part
pink RTV. Sets up in 24 hours, no shrinkage, and stays workable for
years.

Matthew Crawford
www.MatthewDesigns.com


#4
one experience with an RTV mold involved a mold form that clearly
wouldn't accommodate an attached teapot leg. 

What were you using? Liquid RTV? You can get putty form two part RTV
Silicone Mold Making Material. Seems like that would work.

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay


#5
I have a teapot with a missing leg and must cast a duplicate of
one of the legs that's still attached. Does anyone have suggestions
for the most efficient way to go about molding this? 

What you are looking for is sculpture materials. You will probably
want to make a layered paint-on rubber mold, and then encase it for
support in a more rigid 2 part Mother Mold of plaster-like
investment. Materials for this can be found by Googling for sculpture
mold materials. One high quality source is http://www.polytek.com/
You also might want to check at the silversmithing.com website.

Good luck with your project!

M’lou Brubaker
Minnesota, USA


#6

Smooth on (and I am sure other RTV mold materials makers) has a RTV
putty that you could mold onto the leg and let it set. Then either
cut it off or if not necessary to cut it off, slid it off and pour
in your wax. Douglas and Sturgess in San Francisco and Richmond would
be able to help you. Artie is the MAN so if you cannot get the help
you need from the other folks, ask for him (I must say that the
other folks there are very helpful). They usually ship in 1-3 days,
they are close and if you really need it NOW, it is not too far to
drive to from Napa.

Hope this helps,
John Dach


#7

Hey Jalia,

Long time, no see! I have an idea that might just work for you, if
you’re able to be both resourceful and patient. First, check your
yellow pages for a theatrical supply shop anywhere in your area (or
in our old SF, CA stomping grounds), they will almost certainly have
tubes and/or bottles of a foul-smelling glop called “liquid rubber”.
This ammonia-based, unvulcanized, natural latex suspension is used
in the theater for constructing gory skin effects and scars in
’munchie movies’ (among other thinngs), and can easily be painted
onto any solid surface. If you can locate the stuff, buy a few ounces
of it, paint ten or so coats onto one of the existing legs and use a
blow dryer to cure it. Next, wait a day or so, then peel it off and
fill it with something relatively solid, like a two-part epoxy,
paperweight-type acrylic or, perhaps, an investment powder mix that
you trust. When your filler of choice has cured, make a mold of
that, and cast it as you would anything else (using more sprues than
normal, I’d think, to compensate for mass).

Good luck and best regards,
Doug

Douglas Turet, G.J.,
Turet Design
P.O. Box 242
Avon, MA 02322-0242


#8

About molding a teapot leg, I have done exactly what you are needing
using Coe-Flex rubber base impression material for dental work. It is
a thick 2 part rubbery material that you mix together and apply. It
has a short work time, less than 5 minutes. I use a pallet knife to
work it into the detail, compressed air, blown over the surface helps
if bubbles become a problem. It is very flexible,so depending on the
leg shape you may or may not need to make a cut in it with a scalpel
blade to facilitate removing it from the leg. I use my lowest temp
injection wax to fill the mold.

It’s great for a quick throw away mold, flat baked items work best,
I use double stick carpet tape as a backing, it holds the original in
place and the mold material peels right off. I get Coe-Flex from my
dentist.

good luck,
Kate Hart


#9

Continue from:
https://orchid.ganoksin.com/t/how-to-mold-a-teapot-leg

Wow, everyone, thanks so much for the responses! I haven’t checked
my Ganoksin in a while (but now that I’m sitting in a hotel room at
JCK I have ample time whilst resting my weary feet), and didn’t see
an immediate response, but did manage to arrive at some of the ideas
you all have presented.

The best resource has been a book titled Prop Builder’s Molding &
Casting by Thurston James, which I purchased at Tap Plastics
(www.tapplastics.com), which also sells molding supplies, and, as
the name suggests, all varieties of plastic. I’ve found this store to
be a great resource for many things, and definitely recommend the
book above. It’s given me lots of ideas not only for jewelry, but for
making all kinds of fabulous visual merchandising objects.

I haven’t actually molded my tealeg yet (can we say procrastinating
on an annoying project?), but as soon as I do, I’ll let you know what
method worked best (or didn’t!) Thanks so much everyone!

Jalia M. LaNoue
Goldsmith
Spinelle Fine Jewelers
Napa, California