This liquid rubber consists of Part A and Part B that, after mixing, cure overnight at room temperature to a flexible, high-strength, mold rubber. This makes a durable, easy releasing mold for casting plasters and waxes without release agents, but when used with proper release agents, is also excellent for casting concrete, epoxy, polyester, urethane and acrylic.
Mix Ratio (by weight) | 1A:1B |
Hardness, Shore A | 30 |
Pour Time (minutes) | 30 |
Cured Color | Amber |
Mixed Viscosity (cP) | 2,000 |
Specific Volume (cubic inch/pound) | 27.5 |
Note: Polyurethane rubbers bond tenaciously to shellac! If you have used shellac as a sealer, it must be thoroughly be coated with a release agent. Some recommend release agents include Butcher's Wax, Pol-Ease® 2300, Pol-Ease® 2350, or Pol-Ease® 2500.
Polytek 74-30 has a storage life of at least six months in unopened containers stored at room temperature (60-90°F). Parts A and B react with atmospheric moisture and, therefore, should be used up as soon as possible after opening. After opening, spray Poly Purge™ Dry Gas Blanket into containers before resealing to displace moist air and extend storage life.
Polytek 74-30 is designed to be poured. Thickening agents (such as Cab-O-Sil) and accelerators (such as Poly 74/75 Part X) may be used to change Polytek 74-30 into a brushable material.
When first starting out with these products, we highly encourage you you pick up a copy of the Polytel Manual & Catalog, which fully explains the product and its use.
Size | Description | Price |
---|---|---|
4 lb. (2 qts) | Polytek 74-30 | $47.00 |
16 lb. (2 gal) | Polytek 74-30 | $114.00 |
This is used to accelerate the cure. This is most useful when making brush-on molds, to decrease the time needed between coats. By adding 3% Part X (by weight of the total mix), the working time is reduced to approximately 8 minutes -- in the time it takes to mix the next batch, the previous brushed layer gels enough to apply the next coat. Before use, testing to determine the best amount of Part X to use is advised.
Size | Description | Price |
---|---|---|
1 lb. (1 pint) | Poly 74/75 Part X | $32.00 |
A blast of Poly Purge™ into an open container, just before resealing the lid, displaces moist air and extends the life of polyurethane liquids. Poly Purge™ is heavier than air and is non-flammable and non-ozone depleting. The aerosol-type can has a special nozzle extension useful for directing the gas into the desired space.
Size | Description | Price |
---|---|---|
10 oz. can | Poly Purge™ | $12.50 |