This liquid rubber is a two-component, addition-cure, platinum-catalyzed, flexible mold compound. This product exhibits a tough, knotty tear, making it especially valuable to the mold making industry. This is an excellent mold material for casting polyester, epoxy and polyurethane resins, as well as for waxes and many other materials. Platinum-catalyzed silicones offers advantages over tin-catalized silicones in that they don't shrink, or release alcohol, while curing. Tin-catalyzed silicons do both. Alcohol production can inhibit the curing of polyurethane castings.
Mix Ratio (by weight) | 1A:1B |
Hardness, Shore A | 20 |
Pour Time (minutes) | 25 |
Demould Time (hr) @ 77°F | 4 |
Cured Color | Lt. Purple |
Mixed Viscosity (cP) | 12,000 |
Specific Volume (cubic inch/pound) | 24.7 |
Specific Gravity | 1.12 |
Shrinkage Upon Cure | Nil |
Note: Silicone-based release agents (i.e. Pol-Ease® 2300) are NOT to be used on surfaces that contact liquid PlatSil® rubbers since inhibition and/or adhesion may occure! Instead, we recommend either Pol-Ease® 2350 or Pol-Ease® 2500 as release agents. In addition, avoid using modeling clays containing sulfur, as they also may inhibit curing.
PlatSil® 71-20 has a storage life of at least six months in unopened containers stored at room temperature (60-90°F).
PlatSil® 71-20 is designed to be poured. Thickening agents (such as Cab-O-Sil or PlatThix) may be used to change PlatSil® 71-20 into a brushable material. When brushing PlatSil® 71-20, apply subsequent coats to the previous layer within one hour to obtain best adhesion.
You can accelerate the cure with heat or the addition of PlatSil® 71/73 Part X.
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 |
---|---|---|
2 lb. (1 qt) | PlatSil® 71-20 | $40.00 |
16 lb. (2 gal) | PlatSil® 71-20 | $235.00 |
This is used to accelerate the cure. Mix 71/73X liquid with Part B prior to adding Part A. Weigh and add Part A to the accelerated Part B mixture and mix thoroughly. Pour over a properly prepared mold as soon after mixing as possible. The addition of 1 part 71/73X per 100 parts of Part B decreases the gel time to ~ 1/3 the normal gel time. The addition of 2 parts decreases the normal gel time to ~ 1/4. The addition of 3 parts decreases the normal gel time to ~ 1/6. Experimentation on a small scale is recommended before making a larger mix.
Size | Description | Price |
---|---|---|
4 oz. (.25 lb) | PlatSil® 71/73 Part X | $28.00 |
To thicken PlatSil® 71-20 for brushing on as a blanket mold, add PlatThix liquid to Part B (before mixing with Part A) to achieve varying levels of thixotropy. Experimentation on a small scale is recommended before making a larger mix.
Size | Description | Price |
---|---|---|
4 oz. (.25 lb) | PlatThix | $9.00 |