Things You'll Need
Foam glue (3M Fast 7 spray adhesive or similar)
Foam rubber is used for a variety of purposes on several different things we use every day. It will add cushioning to your sofa or chair or help dampen noise when installed inside the walls of your home. Whatever your plans, there is a pretty good chance your project requires the gluing together of two or more pieces of foam. This project is fairly simply and it requires common glue you will find at the hardware store.
Wash the surface of the foam rubber with a mixture of soap and water. Remove any dirt, grease or stains from the surface. Also remove any paint that is remaining on the foam. If paint is present, use a scrub pad and vigorously wipe it away. Do not use sandpaper as this will damage the foam rubber.
Towel-dry the foam rubber surface and let it air dry for at least 20 minutes until the surface is warm to the touch. Warmth indicates the surface is truly dry, and there is no more water evaporating from the foam. Evaporation will cause cooling.
Apply a generous layer of the foam glue to the surfaces of each foam piece in the area where the two pieces will be bonded together. Allow the adhesive to sit for about 30 seconds or until it becomes tacky.
Press the two pieces of foam rubber together. If they are large foam blocks, hold them together for about 30 seconds and then release them. For smaller foam pieces that will fit inside a hand clamp, secure them with the clamp after pressing them together. Tighten the clamp just enough to hold the two foam pieces in place, but not enough to make an indentation in the foam.
Set the foam on a work bench to dry for four to six hours.