Trimming Spray Foam
Trimming excess spray foam insulation takes time and wastes foam, so skilled spray foam contractors do their best to avoid overfilling stud bays. More trimming is usually required for open-cell (½ -pound-per-cubic-foot) foams like Icynene than denser closed-cell (2-pound-per-cubic foot) foams like Corbond. There are two reasons why 2-pound foams are rarely trimmed: since they have a higher R-value per inch than softer foams, fewer inches of foam are required; and since dense foam is difficult to trim, installers have a strong incentive not to overfill stud cavities.
Like A Sawzall
When ½ -pound foam needs to be trimmed, contractors can use a Sawzall-like tool with a reciprocating blade. One such tool is the air-powered polyurethane saw
manufactured by SprayFoamSaws.com. The polyurethane saw uses a sander motor; it has a 23-inch blade
and a blade travel of 1 ¼ inch. The tool requires an air compressor that can deliver 7 cfm at 90 psi.
Steel Curry Combs
Even the most careful installer occasionally needs to trim sprayed foam; for trimming small amounts of foam, hand tools are adequate.
The most popular hand trimming device is a curry comb. Designed for grooming horses, curry combs come in two basic varieties: rubber and steel. Foam installers are looking for the steel curry combs, also known as spiral curry combs.
A steel curry comb consists of an assembly of concentric toothed steel rings attached to a handle.
They can be bought in tack stores, ranch stores, or wherever equine products are sold When rubbed against cured foam, a steel curry comb abrades the surface. One of the good
things about a curry comb is it leaves slightly larger pieces than other tools, making cleanup easier.
Powered Foam Planes
When a spray-foam job requires a contractor to trim a great deal of 2-pound foam, hand tools are not an option. The fastest way to abrade protruding foam is with a powered foam plane. Foam planes are equipped with spinning brushes or blades..
