Stamps are a kind of tool that makes repetition in clay or ink a snap--and
molds do the same job in reverse! By pressing a textured or dimensional
object in a mold material and allowing it to set or curing it with heat, a reusable negative-image
tool is formed.
Molds can be made out of plaster, rubber, metal, silicone,
and polymer clay itself, of course!
One kind of polymer clay especially made for making molds
was Super Elasticlay, manufactured
by Polyform and sold in 8oz. bars. It is much softer than the other clays,
and takes an impression well. It should be kneaded up for a minute or so
to prepare it for use.
It has been replaced in
recent years with a product called Sculpey
Mold Maker/Elasticlay. Elasticlay will not harden until it is baked, and many original
pieces may not withstand baking, so it is advisable to remove the object
by pulling it cleanly up and away from the mold. When making molds, check to see that
you have a clean impression--if not, wad it up and try again. Then bake
according to directions and do NOT over bake. The molds shown below are made
from Elasticlay.
Elasticlay molds remain
flexible for a while, but harden over time and will crack with heavy use
and age, particularly in a dry climate. The face mold shown above left shows
drying and stress cracks. The button molds take less pressure and have
survived fairly well over 15 years.
Oiling the
clay molds
lightly with vegetable oil is helpful in maintaining the molds
and keeping them from drying out. I use a soft paintbrush to apply it. (not
shown here). PAM, a vegetable oil spray, can also be used but I find it
messier to use.
I have successfully used
Badger Balm, an olive oil based skin care product, in revitalizing very old
and dry Elasticlay molds as well as using it as a mold release.
It also works very well
with silicone molds when using ceramic clay instead of polymer clay to cast
pieces.
Elasticlay and other
polymer clay molds are not flexible, while silicone molds are. All take detail
well. Only the silicone molds remain flexible. Below are shown two molds from
the same button made with silicone and polymer clay.
When using Elasticlay or
polymer clay to make a mold, the original piece to be cast must be treated with a mold release such
as talcum powder or cornstarch. Brush it all over the object including
the edges, then press the piece onto a like-sized lump of Elasticlay or
polymer clay placed on the work surface. Do this smoothly, without rocking or setting
it at an angle. This takes a bit of practice! When using powder as a mold
release, I use a small makeup brush and an old mints tin to keep the powder
contained. A "ponce bag" is also very useful for powdering flat
areas. This bag is made with a square of fabric that has an amount of powder
placed in the center, then the edges of the fabric are brought up together and
a rubber band is used to hold it all together and keep the powder contained.
Rub this very lightly on flat surfaces to apply powder. Corn starch can also
be used instead of talcum powder. Water used in a misting bottle can also be
used as a mold release when working with polymer clay.
Polymer clay or silicon rolled out flat into sheets can be textured with stamps,
lace, pasta, wires, and all sorts of items to make texture sheets for transferring
your own overall / large scale patterns to clay. Flat sheets have the
advantage of being flexible enough to wrap around contoured objects, or to go
through the pasta machine with polymer clay sheets.
My
molding compounds of choice are two part silicone molding materials.
There are many brands on the market, and each is a different color. In this
photo, blue is Alley Goop, pink is Miracle Mold and yellow is Amazing Mold
Putty. AMP is available at Hobby Lobby and other craft stores.
No matter which brand
you use, it comes in two
separate containers, and the silicone and the catalyst are mixed together
in equal parts at the time of use--mix till the colors blend to a uniform
solid, and then press the item to be molded into a smooth ball of the silicon
mixture. No release agent is ever needed when using the finished molds with
polymer clay, wax, soap, or food like chocolate. However, when using them with
ceramic clays, I find a very light coating of Badger Balm to be necessary for
a clean pull.
When making a mold with
silicon, check to make certain that the item
is cleanly embedded but don't rock it or move it around. The silicon material begins to set up VERY quickly, and in just a few minutes becomes
too stiff to take as clean an impression, so it is important to mix it
up in small batches that are going to be used immediately. Depending on
the size of the cast item, it will take between five and thirty minutes
to set up completely. The finished silicone molds stays very flexible and
they will "pop" right off the item being cast. Clay can be baked
directly inside these molds (this includes the liquid polymer clays), or
raw clay pulls can be popped put easily and then altered before baking.
I like the molds I make with this stuff so much that I re-cast all my
button molds and faces using it, and have used it to create all my new
molds for several years now.
Pulls from both the button molds and the face mold shown at the
top of the page were
made using a pale terra cotta colored clay.
Details with more clay were
added and the piece was baked to form an original that is also a first generation
repeat of the original face and buttons. This piece was cast in the silicone
Miracle Mold as well.
Now I am able to make
many repetitions or "pulls" from the mold and decorate each in a
different way.
When a small
irregularity in a mold--whatever its composition--occurs, it still can be a
valuable tool. There is a slight flaw around one of the eyes in this complex
mold shown above but it is quite easy to smooth that out before baking.
The first piece on the left (of the four
above) is the original used in making the mold. It has been stained with black
acrylic paint, Varathane, and copper Pearl-Ex Powder. The other three faces
are pulls from the mold. Though two generations away from the original face,
the detail is still clear. Different colored clays, powders, paints and stains
are used to give the different finishes to each.
The faces shown below
are pulls from the silicon mold of the original face. The first face on
the left is direct from the mold with no smoothing. Very little clean-up is
required with these molds. Notice how a little acrylic paint, mixed with Varathane
as a binder, really changes the look of the features! The amount of
"makeup" applied to a baked face changes the character's look--go
from innocent to high fashion complete with slick lip color and eyeliner...its
all in the application, done in steps and layers.
Making large and complex molds like these does use up a lot of molding
material, and also offers more opportunity for small errors. Its a good
idea to practice making molds for a little while with clay before moving up to
silicon. Even now that my mold-making
skills are in good practice, I like to try the larger pieces like doll
faces in polymer clay first. This allows me to see how the pull from the
mold will look---sometimes I don't like it enough to commit it to silicone,
and its easy enough to check it first, then remake or remodel the original
piece as needed! It
is well worth the investment for the serious professional who wants precise
detail in their casts, and also for those who work in other media like
PMC , ceramics or paper. The faces shown below are made of ceramic clay and
have not yet been fired or glazed.
click here to see face
cabochons and pendants
click here
for a tutorial on making faces and molds
