Partall® One-Coat
is a water-based Polyvinyl Alcohol (PVA) coating
comprised of water-soluble, film forming materials.
Commonly used as parting film between polyester,
vinylester or epoxy resins and various mold surfaces or
as a release barrier when making rigid support shells
for elastomeric rubber molds. Partall®
One-Coat contains 2 – 3 times the solids
content of standard PVA giving it a thick viscosity that
builds quickly. The solvent-resistant dry film releases
easily from mold or part surface or application
equipment. Removal is by peeling off in a continuous
skin or by dissolving with water and scrubbing with a
soft bristle brush or sponge.
PREPARATION OF MOLD SURFACE
Porous molds such as
plaster or wood should first be sealed with Formula Five®
Mold Sealer or its equivalent or with an application of
Partall® Paste #2 mold release wax. Allow
sealers or mold release wax to dry properly before
applying PVA. Mold should be thoroughly dry and free of
contaminants such as air compressor oil or silicones to
prevent fish-eyes or other cosmetic flaws in the PVA
film.
DIRECTIONS FOR
USE
Partall®
One-Coat is ready to use as received but may be diluted
with clean water up to a ration of 1:1 to suit
application method. Normally applied over mold release
wax such as Partall®
Paste #2 or Formula Five® Mold
Release Wax although may be used as a stand alone mold
release. Safe for all non-porous, non-absorbent
substrates.
Apply Partall® One-Coat to mold surface in an
even continuous coat with a brush, sponge, or roller and
allow complete drying before molding parts. If size and
shape of mold allows, application may be made by
flooding the mold surface with PVA and tipping to drain
off excess. Test for dry state by gently pressing finger
into film, if PVA comes off of mold onto finger or if
finger impression is left in PVA the film is not
completely dry.
The goal is complete coverage with a smooth and glossy
film without voids, separation or pin holes. Dry PVA
film thickness should be 1 - 4 mils or 25 – 100 µm
(about the thickness of an industrial-type trash bag) to
protect mold surface from solvents found in thermoset
casting or fabrication resins, paints and adhesives. A
wet film thickness of 10 mil (250 µm should yield a dry
film thickness of approximately 2 mil (50 µm).
Do not begin molding until surface is completely dry.
Drying time is approximately 120 minutes at 70 °F (21
°C) with 50% relative humidity. Factors such as humidity
and ambient air temperature may cause drying time to
vary. Mechanically moving air over wet PVA surface or
heating mold surface will accelerate drying time.
The information and recommendations contained in this bulletin are, to the best of our knowledge, accurate and reliable. No guarantee of their accuracy is made, however, and the products discussed are sold without warranty, express or implied and upon conditions that the purchasers shall make their own tests to determine the suitability of such products for their particular purposes and uses.
