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Fimo, Sculpey

I believe James meant to write that Fimo and Sculpey are cured at 250
degrees F.(actually 265 degrees F for Fimo,)not 350 F. They are
polymer “clays”, in other words, a malleable plastic substance.The
manufacturers are quite adamant about avoiding overcooking. Also, I
have found that Sculpey can be brittle, and despite polymer clays’
hardness, they can be scratched with a fingernail. Sally

I was wondering if anyone had any concerning the effects
of time on Fimo or Sculpey. When this material first became commonly
known and readily available a friend of mine told me that it had
already been around for quite some time. He thought it had been in use
for at least twenty years (this was ten years ago) and had been
developed as a material to make miniatures and furnishings for
dollhouses. He told me at the time the greatest drawback of the medium
was that it shattered with age.

I had done some experimental work with Sculpey, wasn’t wild about it
and just threw the test pieces in a box. When I came back to it 7
years later and picked up some of the small very 3D works I had
created, they did in fact with very little applied pressure, shatter
between my fingers. (I had followed all the instructions concerning
use and curing.) As a result, I never considered it for jewelry
pieces. Does anyone have any about this? Has the material
been improved to avoid this negative aspect or should it just not be
used dramatically sculpturally? Does it only shatter if it is thin and
projects off the surface so it is not in a massive chunk like a bead?

Sally mentioned that she has also found it to be brittle. Anyone else
want to comment? I know this raises the issue of permanence of
materials. I don� t mind doing disposable artwork if I know that�s
what I�m doing. I do, however, mind spending hours on something that
I think will last indefinitely (longer than I) with proper handling
only to discover that it has a �shelf life�.

Linda M

Hello Linda,

Fimo is a PVC with a softener inside, If you bake in an oven at 140
degrees Celsius some of this is evaporating and converting into non
softening stuff. This means the PVC bindings are now less lubricated
and create some bindings. this means the clay gets harder. Now is the
problem that the PVC strings in the clay are lose and lubricated by
the softener. removing this softener make some parts of the strings
attached to each other. This process is speed up in an oven. But some
softener is necessary to keep the PVC elastic so that the strings
will not break. Over time the softener will evaporate and your FIMO
gets brittle. You can slow this process by varnishing with a water
based varnish. The same stuff you can use on wooden floors. Now you are
thinking, there are more thing made of PVC like rain pipes and they
last for 50 years. In the making of these products the PVC string are
better mixed and under pressure formed. There will be approx. 100 to
1000 times more bindings between the strings. this material is evident
stronger. also they do not need (expensive and toxic) softener to make
pipes. The FIMO clay is for forming with hands and needs to be very
soft. So they use the lubrication softeners.

An other thing, normally are plastic softener very toxic (dioxins) ,
I think this is the same with FIMO, but I can not find evidence for
it. But the smell is the same a the toxic softeners . So don’t eat it
and wash your hand afterwards very good. and ventilate when you heat
the FIMO up.

And something else, I think you have seen PVC pipes get white over
time, and maybe wondering why? This is chalk. The industry would like
to put as much chalk in the PVC as possible. The chalk is much cheaper
than PVC, so they put just enough PVC in the pipes to fulfill the
requirements. On the rain pipes the top layer of PVC is evaporating
and braking of (microscopic seen) due to UV light and ozone and then
you look at the white chalk particles.

Martin Niemeijer

This is in response to the Fimo/Sculpey questions. My husband [who
is a lurking jeweler] saved this thread of messages for me. I have
been a dollhouse miniaturist for 20+ years. With some of the
questions the have been asked about Fimo and Sculpey, thought I would
add my 2 cents if you all don’t mind, due to this product being used
by alot by miniaturist as well as in the jewelry field.

First, the brittleness and shattering problems from using this medium
is caused either by over baking or baking temperature set to high or
humidity affects it over several years. Hardness process: 265 degrees
{F} - 130 degrees [C] Max at 20-30 minutes. The heat temperature for
the curing process is extremely important. But the problems lies
where people are baking it in their conventional ovens. Conventional
ovens do not have a setting for 265, only 250 or 275, so you kinda
have to guess and set it for somewhere in between and pray that your
thermostat or oven thermometer is correct. Even burnout ovens are
hard to regulate at this temperature. If Fimo is not cured correctly,
it will have a tendency to shatter. One hint is to get your oven to
exactly 250 degrees and let it cure for about 10 minutes longer than
normal. But NO LONGER than 40 minutes max!! If Fimo is over baked,
it will release toxic fumes. This usually does not happen unless it
is over baked.

After your curing process is completed, let it cool completely. The
company that makes Fimo, also makes a treated varnish specifically for
this type of clay. This will seal the Fimo so it will not absorb as
much dampness from humidity. When left unsealed and exposed to
humidity changes over several years will also contribute to it
shattering. The varnish comes in a matte or gloss finish and can
usually be purchased at craft stores with other Fimo products.

One other thing that may contribute to the shattering is mixing the
Fimo with other things, i.e.; Mix Quick and other softening agents.
Mixing different colors together is fine but when you start adding
softening agents to it, it breaks the Fimo down and will cause it to
get brittle as well. Best way to soften Fimo or Sculpey is to sit on
it for a while [and for you ladies - stick it in your bra - LOL
sounds funny but it works] body heat is the best way to help get it
soft enough without crumbling in your hands until it is workable.
They sell products like “Friendly Clay” which is basically a bag that
has a hot pack inserted, but use with caution. Since you cannot
regulate the temperature of the hot pack, it could start the curing
process before you even get a chance to work with it. If that
happens, then it is lost and just throw that piece in the trash
because it will not cure correctly in the oven if the curing process
has already been started by the heat pack, then stopped and started
again in the oven.

Hope this info helps!

Melissa Pernell
TMP Miniatures
Specializing in handcrafted miniatures and founders
of the Handcrafters Miniature Guild

Thank you Melissa for the on fimo/sculpy problems - I
have been making jewelry since Sept this year with it, i.e. Sculpt
flowers and women heads with hats of the 20th century, I also weave
background in metal. I sure hope that they don’t become brittle &
break - they seem strong though, so far - I have dropped them on a
hard wood floor and no damage - Is acrylic spray good enough to keep
out the moisture? thanks for your article it was very informative.

Aileen Geddes

Dear Aileen, Your very welcome for the and glad I was
able to help! As far as using an acrylic spray on the Fimo or
Sculpey, it may work, but cannot guarantee the results. In some
instances I have heard that the chemical makeup in these products has
a tendency to make some sealers yellow over time. So because of this,
the company that makes Fimo created a sealer/varnish where the
chemical compounds will interact and bond together, supposedly
creating a permanent seal that will keep out moisture and greatly
reduce the risk of discoloration. If you or anyone else has any
other questions in regards to these products, please feel free to ask.
I have a friend who has been using these products for many years in
the dollhouse miniature field and seems to know all the in’s and out’s
of these products. If there is a question that I cannot answer, I will
glad ask her and relay the

Melissa Pernell

Martin and Melissa et al

Thanks for all the about Sculpey/Fimo including the
specifics of working with the material

I did mix my Sculpey with a softening agent and I didn’t seal it so
that may account for its brittle state.

I have seen exquisite polymer clay examples in Ornament magazine.
Kathleen Dustin’s figurative beads and evening bags are so
spectacular I couldn’t entertain the notion that they might have such
a limited existence.

Does anyone have a preference for one brand over another?

I would have thanked everyone sooner but was buried under about three
feet of snow.

Linda M