Attach the hose to your vacuum cleaner and vacuum the panels to ensure they are free of dust particles and other contaminates that will interfere with the paint layer.
Dilute water-based primer with water. Use 2 to 3 parts of water for every 10 parts of primer. Acoustic foam is typically gray and needs to be primed white before painting with color. Diluting will allow the primer to absorb into the foam, keeping the foam’s surface pores from becoming clogged.
Paint the primer onto the foam with a bristle brush and use the bristles to work the primer into the foam. Do not paint thick layers. Again, this will help prevent the pores from being filled. Allow the primer to dry once finished. You may want to use a spray primer, however many aerosol products will disintegrate foam.
Dilute water-based paint with water. Use 2 to 3 parts of water for every 10 parts of paint. Paint the foam with a thin coat--again taking care to not fill the foam’s pores. Alternatively at this stage you can use spray paint, as the primer has created a barrier that will prevent it from eating away at the foam.