GUIDELINES FOR USING
MOLD PREPARATION FOR ULTRACAL 30 AND OTHER STONES
||New damp molds should be sealed with wax before
applying GM Foam Mold Release. Failure to do so usually results
in pocked surfaces on the finished foam, and loose skin. An
effective wax sealer can be made by thinning Johnson’s
Paste Wax (or any other commercial carnauba type paste wax)
with 99% alcohol. A good formula for this “alco-wax”
is 1 part wax to 5 parts 99% alcohol. This thin wax sealer is
painted into the mold, then dried. It is also useful to bake
the empty waxed molds at 150º F for 1-6 hours. Thick molds
can take many hours to dry properly. A second coat of wax sealer
can now be applied, dried, and brushed out with a dry brush.
A sheen usually develops on the mold surface.
||On the sealed, buffed mold surfaces, paint a
thin layer of GM Mold Release and allow to dry. Whisk any excess
dried release away with a dry brush. Molds are now ready to
||Please READ THE INSTRUCTIONS prior to starting
your foam job.
||Don’t be a slave to the schedule. All mixers
run differently, and many environmental conditions can affect
how the foam will rise in the mixer. If you understand how foam
latex works, you will be able to adapt to any situation. Call
GM Foam’s technical staff if you need help with your schedule.
||IF YOUR FOAM GELS TOO FAST, cut your refining
time by a minute or two. This means you will be pouring your
Gelling Agent a minute or two sooner. In extreme cases of heat
and humidity, you may need to cut down the time and use less
Gelling Agent. You can use as little as 10 or 12 gms Gelling
Agent per 150 gms Latex Base.
||IF YOUR FOAM GELS TOO SLOWLY, add a minute or
more to your refining time. In extreme cases of coldness and
low humidity, you may need to add minutes to your refining time,
and also add more Gelling Agent, up to 20 gms Gelling Agent
per 150 gms Latex Base.
||Foam that is open to the air ( blobs on the table
) does not accurately reflect the level of gelation inside the
mold. Foam inside a closed mold can take up to 10 minutes longer
to completely gel.
||SLUGGISH OR UNDERCURED FOAM can be remedied by
curing for a longer time. If your oven is tightly packed with
molds, you will need to allow extra time for heating, and you’ll
need to leave enough space between molds to allow even heating.
OVERCURED FOAM loses tear strength and stretch. Cure for less
time in such cases.
||PIGMENTATION is best achieved by using GM Foam
Water Base Pigments. These are specially formulated to be colorfast
in the foam, and will not cause tackiness in the foam the way
other tints will. Remember to add pigment at the beginning of
your run, after weighing your base and components.
||Demolding is easiest when the molds have cooled
to 120-130º F. This is warm to the touch. You can demold
at higher temperatures, but it is hard on the molds, and causes
cracking. It helps to have a thin wooden stick to insert between
the mold halves as they are opening. This wooden stick can be
used to carefully pull the foam away from one side of the mold,
leaving it intact on the other side. The foam is then powdered
with talc and removed from the second half of the mold.
||IT IS VERY IMPORTANT TO WASH FOAM PIECES. They
should be placed in a container of warm water with a few drops
of liquid dish washing soap or baby shampoo added. DO NOT USE
TOO MUCH SOAP. Gently squeeze the water into and through the
pieces. Rinse in clear water until no trace of soap or residue
is left. Press the water out of the pieces on cloth or paper
towels. Do not wring. Dry pieces flat, or on forms that match
their natural curvature, so wrinkles won’t set in. IT
IS IMPERATIVE TO DRY THE PIECES BEFORE STORING. Wet pieces stored
in airtight baggies will develop a sulfur smell.
||When molds are used repeatedly, a brown residue
builds up on the mold surfaces. This buildup can be scrubbed
out with 99% alcohol and a short bristled brush. Only use enough
pressure to lift the residue; excessive scrubbing can remove
precious mold detail.
STORAGE OF PIECES
When foam pieces have been washed, dried, and powdered, they are
best stored resting in their natural curvature in airtight containers
away from light. It is convenient to use either zip-lock plastic
bags, or plastic refrigerator containers that have airtight lids.
These baggies or or plastic containers are then stored in a cardboard
box or any other opaque container that can keep out the light. If
stored in this way, pieces can be stored for years without any deterioration.
If a foam piece is stored or left to air out with a crease or fold
in it, the piece may take a set with a permanent crease line or
indentation. Store pieces in their natural curvature.
||Read the instructions before starting. Refer
to the material safety data sheet (MSDS) for more information.
||Have adequate ventilation to remove ammonia fumes.
||Wear safety goggles and gloves when working with
||Do not let foam components come into contact
with skin. If this accidentally happens, wash with soap and
water as soon as possible. Clean up spills.
||Wash your hands after working with foam. Never
eat, drink, or smoke without washing first.
||Anyone using foam latex should keep a set of
material safety data sheets nearby in case of emergency.
Be sure to mail in your MSDS request card to obtain a set for
WARNING: Never use a household oven for curing
Fumes given off by curing foam are toxic for food use.
Keep these & all chemicals out of reach of children
INSTRUCTIONAL DVD IS AVAILABLE FOR THOSE WHO WANT
TO LEARN MORE ABOUT HOW FOAM LATEX WORKS.