Rebound™ will not stick to most surfaces, so surface preparation is minimal
Rebound 25 is soft, flexible and is good for making molds of models with deep undercuts. Depending on model configuration, Rebound 25 can be inverted as a glove molds.
Rebound 40 is harder and less flexible. These products are compatible. For example, you can apply two coats of Rebound 25 and back it up with two coats of Rebound 40.
This product must be applied in layers. Mold makers generally find that four thin layers (minimum 3/8” thickness) is suitable for a strong, working mold. Using a stiff brush, the first coat of rubber should be applied in a very thin layer to capture intricate detail. Use dabbing strokes, especially around undercuts, to reduce entrapped air. Subsequent coats will add strength to the mold. Let the first coat dry for 60 minutes at room temperature until it becomes “tacky” before adding the next coat. “Tacky” is defined as sticky to the touch, but does not come off onto your gloved finger. Once “tacky”, you are ready to apply the next layer. Tack-time can be reduced with mild heat (hair dryer or heat gun). Repeat until the necessary mold thickness is achieved.
Coverage: 1 gal. unit=7 sq.ft. (0.65 sq.m) - 5 gal. unit=35 sq.ft. (3.25 sq. m)
Note: Although not necessary, adding a small amount of Silc-Pig® color pigment to every other mix of rubber will help you distinguish one layer from the next. Ensures that you apply a thorough coating each time and help build uniform layers.
Option: Add Thi-Vex® thickener for greater thixotropy—adding a small amount of Thi-Vex® will thicken the rubber for filling deep undercuts and detail. Amount to add? 1% of the total volume of your mix will increase thixotropy substantially.
Option: Add Smooth-On Silicone Thinner to your initial mix to lower the viscosity of your “print coat”.
Apply A Support Shell - Once the mold is fully cured, a rigid support shell (mother mold) is necessary to support the rubber mold during casting.
Note: These products will not work with modeling clay containing sulfur under any circumstances.