Flotation Foam is a 2-part polyurethane foam that, when mixed in equal parts and put in place, this foam will be soundproof, insulate or provide extra buoyancy. 4 lbs. 2 gallon density polyurethane flotation foam kit; Consists of 1 gallon of Part A and 1 gallon of Part B and produces 4 cubic feet. Once fully cured, this foam can be laminated with any type of polyester, epoxy or vinyl ester resin without melting. 4LB density also works well in floating bait or taxidermy applications, as well as many other sculpting, casting, carving and other filling applications. All provided expansion rates and times are temperature critical. Temperatures below 75° F will decrease the expansion rate, therefore requiring more foam. Ideal working temperature is 75° to 80° F or higher. Accurate measurement of these products is extremely critical. Working time before foaming approx. 45 seconds Time before full expansion: approx. 5 minutes, Manufacturer: Fiberglass Supply Depot Inc.