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| Polyurethane
Foam |
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Foam
R-8 RTV Rigid Casting Foam
Description
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Foam
R-8 is a self-skinning, castable, rigid foam which can be
poured into closed molds at room temperature and packed to
a finished density of 10 to 20 pounds per cubic foot. It produces
parts and decorative objects replicating wood, terra cotta,
stone, any many other materials. |
Mold
Preparation
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Foam R-8 replicates minuscule details from a mold or pattern. When poured on improperly prepared surfaces, it may stick. To avoid damaging a valuable mold, perform a trial casting on a surface finish comparable to the final mold. The Thickener for Platinum Systems 71 and 73 Series do not need a release agent with Polyethylene and silicone rubber molds. To help extend mold life, add a suitable barrier coat with Barrier PF. Ease PF must be applied to the mold before applying Barrier PF. Latex, polyurethane rubber, such as 74 or 75 Series, or metal molds require a coat of a suitable release agent and must be dry. In order to avoid distortion under packing pressure, mold rubbers should be stiff. |
Mixing
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All molds and equipment must be prepared before mixing. Atmospheric moisture contamination may degrade product integrity and cause excess foaming, unexpected high pressure and poor cured properties. The containers of Parts A and B should be used or resealed tightly after opening. Purge can be used to displace moist air in opened Part A and B containers before resealing for enhanced shelf stability of the liquid products. Stir Foam Part B prior to use. In two mixing containers, measure or weigh Parts A and B separately. Polyethylene buckets are exceptional and often reusable. Immediately combine Parts A and B and mix with a Turbo mixer for 30 seconds. Foaming will begin immediately, so pour mix into cavity as quickly as possible. The foam will rise in the mixing container and the mix may be lost if too much time elapses. |
Curing
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In
order to achieve adequate surface detail and mold fill use
packing Foam R-8 to a 10 - 20 lb/ft3 density. Prior to rise,
firmly clamp a lid with small vents in place to allow air
to escape as foam rises. Avoid stirring or other movement
that will cause cells to collapse after foam begins rising.
Castings should stay in the mold until thoroughly cured. Parts
demolded too soon may be deformed. The mold should be warmed
to between 75¼F and 85¼F prior to casting the first part for
best casting results. It will maintain heat for continued
production after a mold is heated and cycled. |
Finishing
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Cured Foam R-8 should be painted or sealed for exterior use because it will yellow and chalk when exposed to sunlight. It can be easily machined, drilled and sanded. Adhesion of the coating should be checked carefully over a period of time to insure it is satisfactory to be painted or coated. Most oil paints work correctly if all mold release is removed by detergent washing. Spray a primer/barrier coat, such as Barrier PF, and allow it to dry in the mold before casting for a pre-primed section upon demolding.
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Cleanup
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Clean tools before the foam hardens. Alcohol (shellac thinner), acetone or MEK are excellent cleaning solvents, but are highly flammable. Hardened resin can be removed easily if work surfaces are waxed or coated with 2300 Release Agent.
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Storage
Life
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The product will last at least six months in unopened containers at room temperature (60-90¼F).
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Warning
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See
Methods of Use. Foam R-8 is highly flammable. Handle sanding
dust and other easily ignitable forms of these products with
extreme caution. Read MSDS and container labels before use. |
Physical Properties: |
Mix ratio, by weight or volume
Mix viscosity (cps)
Cream time (seconds)
Rise time (seconds)
Tack free time (seconds)
Demold time (minutes)
Free rise density (lb/ft3)
Molded density (lb/ft3) |
1A:1B
1100
45
140
180
10 - 15
8
10 - 20 |
Packaging: |
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Containers |
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Size |
Net lbs. |
Product |
Weight/lbs. |
A |
B |
A |
B |
Foam
Mix Ratio 1A to 1B |
4 |
1 qt. |
1 qt. |
2.0 lbs. |
2.0 lbs. |
16 |
1 gal. |
1 gal. |
8.0 lbs. |
8.0 lbs. |
80 |
5 gal. |
5 gal. |
40.0 lbs. |
40.0 lbs. |
900 |
55 gal. |
55 gal. |
450.0 lbs. |
450.0 lbs. |
Ease PF-Release Agent: 1 qt. (2.0 lbs.), 5 gal. (40.0 lbs.)
Barrier PF Barrier Coat: 1 qt. (2.0 lbs.), 5 gal. (40.0 lbs.)
Purge: 10 oz. can, Case of 12 cans |
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