>Dose anyone know the difference between CST'S SPYDER >(Blue) FOAM 2.3 lb./cu. ft and there High Strength (Blue) Foam 2.3 lb/cu ft. >They are both rated at 60 psi compressive strength.
Recently I measured both. I cut 1/2" thick, 1" x 1" blocks of each type of foam. The specific Dow sample I had is also called "Plazamate". The 1" square faces were carefully fine-sanded perfectly flat. I weighted them on a precision indoor scale. The densities were identical at 2.30 lb/ft^3. Each block was placed on a bathroom scale, sandwiched between two small metal plates. A drill press was then lowered onto the top plate to slowly crush the foam, while noting the indicated load on the scale. The load leveled off when the foam started to flow in axial compression. The max loads: Spyder Foam : 85 lbs (85 psi) Dow 60 Hi-Load: 75 lbs (75 psi) The loads at the onset of deformation surely were slightly lower, but this onset was impossible to detect reliably. In another test I placed two blocks face-to-face, and crushed them together. The Dow started to flow before the Spyder did. This confirms my subjective observations that Spyder has slightly more dent resistance than the Dow Hi-load. This may or may not be worth Spyder's higher cost. Both foams are vastly more dent-resistant than the lighter Dow grades. - Mark RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
