FOAM INSULATION - Continued
Surfaces to be bonded or foamed MUST be clean. Metals should be cleaned with
solvents, " using clean wiping cloths (use only once), followed by an abrasive cleaning of steel or suitable
cleaning of aluminum. Remove blast with dry compressed air.
Chemicals should be stored in a cool and dry location. Before using, check that shelf
lives of chemicals have not been exceeded. Carefully cover and seal partially used chemicals.
After performing foam procedures, check whether the proper foam penetration and
expansion has taken place, so that all voids are filled. Use suitable bracing to prevent bulging during the
All surfaces which contact foam must be primed for proper bond strength and corrosion
When grinding with rotating wire wheels, be sure to direct residue away from the surface
After foam has cured, cut away excess foam and seal any exposed foam to reduce the
opportunity for dirt to accumulate and bacteria to grow, to prevent entrance of moisture, and to improve
cosmetic appearance of the container.
In general, all materials involved in a foaming procedure should be at the same
temperature. Note carefully the curing time of foam and adhesives. As a rule, curing time is reduced as
ambient (outside) temperature increases. This may affect the manner in which the repair is planned.
Calculations regarding the proper volume and mix of chemicals generally assume a minimum
temperature of 68 (20 ). The temperature of panels during foaming must not be less than 50F
When panels do not properly adhere to foam, air pockets develop and water vapor can
condense. In addition to decreasing the insulating property of the foam, vapor invites bacteria, fungi and
Bulges in panels do not necessarily mean that the foam has been damaged. Careful
visual examination and probing is recommended to avoid unnecessary repairs. Air pockets can be
repaired using liquid adhesives injected into the skin.
Foaming Panels Less Than Half Height.
When foaming in a closed cavity, the panels on both sides must be supported. The
foam expands naturally, but is restrained by pressure from the panels. Use plywood back-up plates
pressed against the repair panels by mechanical or hydraulic means.