Commonly sold in spray-on form out of aerosol cans, foam adhesive is a particular type of bonding agent used to join an assortment of porous materials. Foam itself comes in many varieties. From polystyrene to polyurethane, known as foam rubber, foam has a variable level of porosity. Foam rubber can be quite airy and very porous, while polystyrene or Styrofoam is harder and less porous. Foam adhesive is engineered to bond foam to itself. In addition, it can effectively bond foam to other materials as well such as various kinds of fabric, wood, certain plastics and metal.
Foam Adhesive Options
Foam adhesive comes in all-purpose varieties such as 3M's Super 77 spray adhesive, good for bonding foam to numerous other surfaces. It also comes in more specialized varieties, for example, polystyrene adhesive or foam and fabric adhesive. All-purpose foam adhesive features a high tack, does not wrinkle surfaces, nor does it stain them. It is water resistant and quickly forms a bond between several lightweight materials. Heavy-duty foam adhesives are designed to form a stronger bond. The same idea is at play, only the chemical makeup of the adhesive increases its strength.
Foam adhesive, most commonly, features a low soak-in rating. What this means is that most of the spray-on adhesive stays on the surface of the foam despite the fact that it is so porous. The result of this is that foam more effectively bonds to other surfaces including other foam. Depending on the grade, foam adhesive will resist heat up to a point.
With certain brands, the width of the spray pattern may be adjusted when applying the adhesive. Foam aerosol spray adhesives typically feature a low mist application in either a web-like or controlled lace pattern. For extra strength, double apply the adhesive layer before bonding the surfaces. As with many adhesives, application should only be undertaken in a well-ventilated area.