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 |