How To Make Custom Foam Hollow Rocks for Outdoor Speakers

To start the gun, eject a small amount of material into a waste bucket. This is done to ensure a good mix and to put only the well mixed material into the mold. Position the Rebound® 25 brush-on mold to complete the support shell for spraying. Wear a Niosh approved mask.

Be sure to deliver an even coat across the surface of the mold. The foam will quickly begin to expand and form the hollow shell. Add another quick coat to ensure a strong, even piece.