TrueCast 65-Slow is a versatile two component liquid castable polyurethane elastomer. TrueCast 65-Slow combines high strength and elongation with excellent chemical resistance to create durable flexible molds or parts. It is insensitive to typical environmental moisture, has high strength and low viscosity. Some features for TrueCast 65-Slow include good grease and oil resistance, good flow into fine detail, good dimensional stability and good adhesion between pours. It is also tough, with high tear strength and insensitive to inhibition.

Application and Mix Ratio

Component A and component B are supplied in 1 and 5 gallon plastic containers. Component B should be thoroughly mixed before using. Component A does not need mixing. Carefully weigh out 100 parts Component A to 100 parts Component B by weight. Mix together for 1 to 2 minutes by hand using a spatula for small batches (1/2 gallon or less), or electric drill and jiffy mixer for larger batches. Use silicone mold release, even when using a silicone mold to avoid residual tack. Molds may be dusted with talc powder before pouring in liquid to produce a tack free permanent surface on cured parts. TrueCast 65-Slow is fully cured in 24 hours at 72°F. Colder curing temperatures will lengthen cure times. Warmer temperatures will greatly reduce working and cure times. Curing can be heat accelerated (150°F/ 8 hours) to speed up processing. Use methyl ethyl ketone (MEK), acetone or mineral spirits for clean-up.


Working Properties

Mix Ratio By Weight

100 parts A/ 100 part B

Mix Ratio By Volume

100 parts A/ 99.98 parts B

Viscosity @ 72°F (A Side)

2700 CPS

Viscosity @ 72°F (B Side)

2000 CPS

Viscosity @ 72°F (Mixed)

2300 CPS


Part A:



Part B:

Light Beige



Light Beige

Working Life @ 72°F

15-25 minutes

Full Cure Time* @ 72°F

72 hours

* Set time and Demold time depends on temperature and relative humidity.


Physical Properties

Specific Gravity (Part A)


Specific Gravity (Part B)


Specific Gravity (Mixed)


Weight/Gallon Part A

8.73 lbs.

Weight/Gallon Part B

8.73 lbs.

Weight/Gallon Mixed

8.73 lbs.

Cubic inch per lb. of product

26.19 in3/lb.

Hardness @ 72° F

ASTM 2240-85

55-65 Shore A

Tear Strength

ASTM D-624

375 lb./in.

Tensile Strength

ASTM D-412 die C

1700 psi


ASTM D-412 die C


Modulus (100%)

ASTM D-412 die C

437 psi

Modulus (200%)

ASTM D-412 die C

675 psi

Modulus (300%)

ASTM D-412 die C

960 psi


Clean Up

Dispose of all empty TrueCast 65-Slow component containers in accordance with local, state and federal regulations. Empty component containers can be rendered non-hazardous by rinsing the containers with a small amount of mixed material and allowing material to cure for 24 hours. The containers will then contain non-hazardous cured urethane.

Storage and Shelf Life

TrueCast 65-Slow is shipped from the factory in sealed containers. The containers should be stored in a cool, dry area that is protected from direct sunlight and moisture. Storage temperatures should not exceed 80°F. The shelf life of the factory sealed containers stored under these conditions is six months. Containers that have been opened should be resealed immediately after material has been removed in order to prevent solvent evaporation.


Shipping Class: Class 55 Non-hazardous