GI-739 is a thixotropic (resistant to flow) tin catalyzed silicone designed to be used when painting or spraying onto vertical surfaces. GI-739 does not contain the mold rotting thixoadditives widely used today, but offers the end user the same ease of use and detail reproducibility. When catalyzed with one of our library life extending catalysts (see supplemental products) and stored correctly, a longer life of the cured mold should be expected. Its high tear strength, elongation and tensile strength make it an excellent choice for any mold making application. It is also resistant to inhibition by most common mold making substrates, eliminating the need to use mold sealers.
Typical Properties Uncatalyzed Compound Color Base: White
Activator: Teal
Viscosity (cps) Base: 325,000 - 400,000
Activator: 900 - 1100
Mixing Ratio (B/A) By weight: 100 / 10
By volume: 100 / 11.1
Mixed Viscosity 300,000 - 350,000
Working Time 1 to 1.5 hours
Cure Time 16 - 18 hours
Shelf Life 6 months
Vulcanized (cured) Properties (7 days @ 70° F / 50% relative humidity)
Shore A Hardness (±4) One day: 15 7 Days: 18
Tear Resistance (ASTM D624) 70 ± 10 ppi
Tensile Strength (ASTM D412) 275 ± 25 psi
Elongation (ASTM D412) 500 ± 50 %
Service Temperature (° F) -60 to 350
Shrinkage 0.10 %
Specific Gravity 1.10 Coverage (in3 / lb) 25.2