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Crisp mold-making material for PMC


#1

This is for all you folks who play with clay! I purchased three
wonderful stamping dies on EBay (), one of which is a
beautiful, but very finely detailed duck pond scene. The design - two
ducks in flight over a marsh - is very shallow (don’t know how else
to describe it); so the 2-part RTV mold-making material I tried won’t
work… or perhaps I should say, I’d never used this stuff before,
and I ended up with a coarse rubbery mess when I and the result were
"done" (as recommended by the vendor from whom I purchased the stuff,
the studio and my hands were both very warm before I attempted to
combine the two parts). I’m thinking the best thing would be some
kind of paint-on substance, but the result has to be both pliable
enough to peel off the stamping die once set, yet stiff enough to
allow the resulting mold to have PMC pressed into it.

I plan on using standard PMC if/when I ever find an appropriate mold
making material, hoping that the shrinkage for this version will
bring the item down to a more “charm” appropriate size from it’s
original 1.5" x 1.25" oval size. A version in PMC+ or PMC3 would
make a perfect pin.

I have several possible ongoing uses for this and a larger single
"duck in flight" - a local Waterfowl U.S.A. group, and two
Adirondack-themed galleries. I’m anxious to get a few created and
fired to show, but I’m stuck at this mold-making step! If anyone’s
got a favorite mold-making substance they’d like to share, I’m all
eyes!

Thanks!
Karan


#2

Hi.

I’ve been playing with PMC and making lots of molds with Rio’s “Cold
Mold” 2 part comes out pinkish. Have been able to get very fine
detail of of all kinds of things. And it is coming out great in the
PMC. There is also a yahoo pmc group they are very talented and
freindly people with a wealth of info to share.
groups.yahoo.com/group/MetalClay Have fun, I am!


#3
to describe it); so the 2-part RTV mold-making material I tried
won't work... or perhaps I should say, I'd never used this stuff
before, and I ended up with a coarse rubbery mess when I and the
result were "done" (as recommended by the vendor from whom I
purchased the stuff, 

It sounds like either

a) your RTV stuff wasn’t mixed properly – i.e. not equal amounts,
not mixing well enough or

b) it’s old

I’d say you’re on the right track, buy a new batch of RTV 2 part
silicone mold making material, and try again.

If you’d asked what to use for this project, that’s what I would
have said.

The paint on stuff is a pain to work with and tears easily.

I don’t quite get what you’re molding. Is it an old lead printing
block?

Let’s see, what are your other choices? Polymer clay, that would not
get as much detail as the silicone RTV.

Any reason why you can’t work directly with the stamp?

You could print the stamp with ink on paper and have a rubber stamp
made at Ready Stamps for $30.00.

Good luck,

Elaine

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


#4

Put the stamp (rubber part only) on a piece of mirror or smooth
glass and stick it down either with super glue or smooshing a very
thin layer of “Clean Clay” (which doesn’t have any sulfer-this is
critical-NO SULFER). Use Clean Clay and build a wall around the stamp
leaving a 1/2 inch of glass showing. Smooth it down on the inside so
if you were to put water in, it would not leak out. Picture a castle
(the stamp) and a mote (the clay wall). Also seal the edges of the
stamp with a little clean clay so “water” won’t get under the stamp
between the stamp and the glass. Just smoosh a line of Clean Clay
around the edge of the stamp.

Use RTV moldmaking material which is mixed with a catalyst and a
throw-away paint brush. Brush a very thin coating over the stamp and
check and remove all little bubbles with the paint brush. Move slowly
and you’ll get all the bubbles out. Fill the rest of the mold with
RTV and put it on a LEVEL surface to cure overnight. It should peel
right out of the RTV (I haven’t used it on rubber. So I suggest
making a mold of another stamp of the same material to try it first.
It could stick to the rubber stamp. If it does, try mold release
spray. I haven’t used that, but I hear it helps.

The result is a mold of the stamp that is the depth of the piece of
rubber the stamp is made of with the detail of the stamp you want in
a negative.

Melt Aluwax (if you want maleability) or injection wax (if you
don’t) into the mold, checking for bubbles (I use a wax pen or
soldering iron). Pop it out after it cools a bit. You can vary the
depth of the final piece by how much wax you put in the mold. Keep it
on a level surface so the thickness is even.

Hope this works for you. I do it all the time. It’s a great
moldmaking technique.

Veronica

(The two-part RTV stuff you mix with your hands isn’t going to give
you fine detail. The RTV liquidy stuff I’m talking about will give
excellent detail on the shallowest of markings. The key is to remove
all bubbles from touching the stamp. I used the two-part putty-like
stuff and it was great on large detail, but tricky to mix.)


#5

Try Sculpey Moldmaker (also called Super Elasticlay). Make sure the
clay is cold and your original is powdered with talcum powder. 8 oz
is only about $10 and can be found in larger “hobby” stores or plenty
of places on-line. It cures at only 275F.

You might also try the liquid latex rubber Mold Builder from ETI.
The only gotcha I’ve hit on it is, that in order to get a mold that
will stand up to repeated use, is to use some medical gauze after the
third coat or so to stiffen it up.

Diane


#6

Hello Karan,

You have a couple of options to create a mold from the duck die.

  1. A two-part silicone moldmaking material will reproduce the design.
    I use Belicold from Rio, but there are others available also, from
    Rio and other suppliers. Micromark carries Belicold under a different
    name. Just look for two-part silicone moldmaking material that cures
    fairly quickly (15-30 minutes). One caveat: don’t try to use this
    type of material to reproduce a design made of rubber. Somehow the
    silicone reacts with the rubber and does not dure properly. Very big
    mess results.

  2. Aquaplast is a thermoplastic (i.e., warm it and it becomes soft
    and moldable). It is the same material that is used for casts for
    broken bones and also the product known as “Friendly Plastic” that
    you find at craft stores (all made by the same company). However the
    pellet form is the one you want to use for your purposes. Their
    website is. Go there and click on “prototypes and craft”, which will
    bring you to the Pellet ordering

Instructions are included with both these types of moldmaking
material.

One last comment, a shallow design in your die will result in a
shallow design in your mold, and hence, the PMC as well. Deeper
originals produce deeper results. OK, so I’m stating the obvious, but
sometimes it helps.

Hope you find this helpful,
Linda Kaye-Moses


#7

Thanks, Diane. I had several off line suggestions to use Sculpey as
well… though several folks suggested Sculpey III. Is this different
from Sculpey Moldmaker? I have no experience with polymer clay,
though have seen a great project for transferring black and white
photographic images onto polymer clay, so perhaps this is a sign that
I need to go down the clay aisle at the local Jo-Ann’s. (Can you cure
this stuff in a regular oven… my husband would divorce me if I went
out and bought one more piece of equipment).

Veronica… your technique intrigues me; but egads, I’m not sure how
comfortable I am gluing down an expensive metal stamping die. Your
instructions gave me a very clear mental image of what you mean,
however, so if I’m not happy with the results using Sculpey, I may
give it a go (though I’m unfamiliar with “clean clay” or Aluwax??).

I like the sounds of the RTV moldmaking material much better…
since my stamping die is not rubber, I’m not concerned about it
sticking. I had envisioned a process something like this when I was
thinking about painting on a mold making substance. Just for clarity,
when you say “Fill the rest of the mold with RTV and put it on a
LEVEL surface to cure overnight”… do you mean more of the brush on
stuff? Or a big gob of the the two-part mold-making material I struck
out on (it IS tricky to mix!!!)


#8
Can you cure this stuff in a regular oven.. 

Here is a quick overview of the potential dangers of polymer clay.
Whether you want to use it at all depends upon who you believe:

http://www.bellaonline.com/articles/art33912.asp

Personally, I choose to believe PIRG, so I don’t use it at all. If I
did, I would only fire it outside in a dedicated toaster oven that
has been proven to hold temperature well. Even the manufacturers
admit that, if it is fired above the recommended temperature, it
creates a cloud of toxic fumes.

Lisa Orlando
Albion, CA, US


#9
I had several off line suggestions to use Sculpey as well.. though
several folks suggested Sculpey III. Is this different from Sculpey
Moldmaker? 

Sculpy III bakes fully hard. The Moldmaker is pliable after baking
and so it’s a lot easier to pick up the fine details with and easier
to pull the mold away from whatever you’re forming in it.

(Can you cure this stuff in a regular oven.. my husband would
divorce me if I went out and bought one more piece of equipment). 

It cures at 275F for 15 min per 1/4" of thickness. I use a dedicated
toaster oven but for occasional use there’s no problem using your
kitchen oven. The main issue on it is that things used in making or
things made from polymer clay shouldn’t be used for eating with
afterwards. Since the oven isn’t actually touching any clay (or
anything else you’re going to eat unless you’re as bad a cook as I
am) it should be fine.

Diane


#10

I had thought you meant you had a rubber stamp. Metal won’t stick to
it. It should work beautifully. If it is a flat stamp, the back is
flat, even better. Clean clay is clay that doesn’t have sulfer in it.
Sulfer will cause the RTV silicone to not cure. So regular modeling
clay etc. won’t work. I’m not sure where to get it, but I can find
out. I got mine from a class I took. I’ll ask the instructor. But if
you put a thin layer around the bottom of the stamp, it will stick.
And it cleans off, so it won’t affect the harm the stamp. It’s clay,
but it doesn’t ever harden. Amazing stuff.

Aluwax is a dental wax that has aluminum in it, so it retains heat
longer and can be manipulated with the warmth of your hands. I use it
for freeform twisty pieces that I sprue and cast. It’s a dental wax
used for filling molds and stuff, I think.

The RTV silicone is liquidy, goopy honey consistency; mixed with a
liquid catalyst which starts the curing process. The only reason you
paint on the first layer is so you can see bubbles and eliminate
them. Then you pour the rest of the same stuff into the mold. You
could just pour the stuff from the beginning, but you end up, with a
detailed mold, with bubbles on the surface of the model, which then
end up cast in silver and need to be ground off, negatively affecting
the piece.

What you end up with is a slightly flexible mold that you melt wax
into. The silicone withstands temperatures up to I think 400 or 500
degrees, so a soldering iron won’t affect it, and you can use it hot
or cold. You can get RTV stuf on ebay for around 15-20 dollars a
quart I think. I can find the website for you. I need to order some
more. But you only use a couple of ounces for each mold, depending on
the size of the piece you are making a mold of.

If you want to try it, I can find the info on the websites. Let me
know.

But use rubber gloves, because the stuff can be messy, and it
doesn’t come off anything. It’s like honey, but it’s rubber when it
cures. Put down paper towels and mix it in a throw-away plastic cup.
Measure precisely and when you’re done, throw everything away. Easy.

Veronica


#11

Hi Karan,

I’m not sure which mold making material you are using, but I’ve had
nothing but success with Castaldo’s Quick-Sil. That said, why do you
need to make a mold? If your stamp has a shallow relief, you could
just press it directly into PMC. You can use a little badger balm or
olive oil on the stamp as a release - but not much is needed.

Good luck -
Jennifer


#12
Clean clay is clay that doesn't have sulfer in it. Sulfer will
cause the RTV silicone to not cure. So regular modeling clay etc.
won't work. I'm not sure where to get it 

Seems like you could just use soft wax instead of the hard-to-find
clay. No?

Noel


#13
Personally, I choose to believe PIRG, so I don't use it at all. If
I did, I would only fire it outside in a dedicated toaster oven
that has been proven to hold temperature well. 

The ideal way to fire polymer clay is in a dedicated table top
convection oven. It that is too pricey for one’s needs, AMACO makes a
special “toaster oven” that doesn’t have the exposed elements – the
toasty part – so that your polymer clay will bake without burning.
That one is about $24.00 and available from your favorite polymer
clay supplier.

Elaine

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


#14

Dear Orchid,

This is Michael Knight at CASTALDO.

We make a silicone rubber putty that is ideal for what you are
trying to do. We’ve used it to take impressions of everything from
coins to tree bark to tire impressions left in asphalt. Also designs
cast in wrought iron, elaborate picture frame moldings, gravestone
carvings, military jacket buttons and lots more.

After the impression is made it’s easy to pour wax into the mold for
further work and laster casting.

It’s simple, and easy to use and not at all messy or gooey or yucky.
No liquids – it mixes by hand and cures in 15 minutes.

The final result is a tough, strong, highly flexible rubber mold
that can be used 100’s of times.

Below are links to our website page on this product as well as the
instruction page for it. And I’ve attached a link to a
still-unfinished brochure we’re doing showing how to use it with PMC
and ArtClay.

http://castaldo.com/english/usinprod/u_quicksil.html

http://tinyurl.com/yst2ft

If anyone out there would like to try a small free sample, please let
me know.

I’ll need your physical shipping address – no P.O.Boxes, please,
and also a telephone number – UPS requires it.

Michael


#15

Wax doesn’t have a stickiness to stick two things together. This
clay seems to work like that and sticks very well. It’s not hard to
find. I just don’t remember where to get it. But I can find out.

V.