Dow Firestop 3-6548 Silicone RTV Foam

Surface Preparation

The penetration opening and all related surfaces must be clean of dirt, dust and loose impediments. Surfaces must also be free of water, oil or other free liquids.

Mixing

Prior to use, Part A and Part B components must be thoroughly stirred in their original containers to uniformly disperse any fillers or pigments that may have settled. When mixing, use clean containers and mixing equipment. If stirred containers stand for more than four hours, re-stir. At time of installation, material temperature should be between 18 and 27°C (65 and 81°F). (Materials can be warmed by placing them in a room at these temperatures for 12 hours.) Please check material temperature prior to use if there is a possibility it is outside this range. To properly catalyze Dow Corning 3-6548 Silicone RTV Foam, add Part A to Part B in a 1:1 ratio (by weight or volume). Mix vigorously and thoroughly for 30 to 60 seconds by hand or with power mixing. The mixed product will begin to foam shortly after mixing

therefore, it should be dispensed in the penetration as soon as mixing is completed. For large-volume applications, the use of suitable automatic mixing, metering and dispensing equipment is recommended. A list of equipment manufacturers is available from Dow Corning. The type and degree of mixing can significantly affect the cell structure and density of the final foam product. Mixing with a 198-g (7-oz) Semco® cartridge will generally result in a slightly higher density than mixing by hand. Hand mixing, in turn, will result in a higher density than power mixing by automatic mixing, metering and dispensing equipment. Likewise, the expansion ratios of foam volume to liquid volume can vary from 2:1 to 4:1, depending on the type and degree of mixing and degree of confinement. If foam rise is restricted or confined during foam cure, densities as high as 0.48 g/cm3 (30 lb/ft3) can result.

Clean-Up

Excess cured foam around the penetration seal can be removed with a sharp knife or blade. Spills of Part A and Part B liquid components can be removed with high-flash-point mineral spirit solvent. Caution: Consult solvent material data sheet for safe handling information. Follow state, federal and local environmental regulations.