Foam Reaction Rates Explained
Our spray foam kits are available in two cure rates or formulations. The cure rates affect how quickly the foam expands (not how much) and how quickly the foam reacts/cures (sets or hardens). As a result of these differences in reaction time, the formulations are better suited to particular applications:
Spray-on foam expands fully within 30 - 50 seconds and is tack-free (not sticky to the touch) within 60 seconds. It is hard enough to cut in 2 - 5 minutes and has completely cured within one hour.
This formulation is best suited for spraying onto walls and roofs where the foam is required to stick and cure quickly rather than drip off. Spray-on foam will not drip if applied in thicknesses of up to 1 inch per pass.
Injection foam expands fully in about 90 seconds and is tack-free within 3-5 minutes. This slower curing formulation is better suited to injection applications e.g. cavity, mould filling and buoyancy applications. Handi-Foam injection foam had US Coast Guard approval for marine applications