How Much Does 4-Pound Pour Foam Expand and What Volume Will It Fill?

How Much Does 4-Pound Pour Foam Expand and What Volume Will It Fill?

Four-pound density polyurethane pour foam is a closed-cell marine foam with greater strength and compression resistance than 2-pound foam. It is commonly used in structural applications, marine repairs, and flotation where additional durability is needed. Because it is denser, it expands less than lower-density foams.

Expansion Volume

• Mixing 1 gallon of Part A with 1 gallon of Part B yields approximately 4.5 cubic feet of expanded foam.
• At ~4 lb/ft³ density, it is heavier and stronger, making it ideal for load-bearing and high-impact areas.

Usage Tips

• Measure both parts precisely by volume for accurate expansion.
• Mix quickly and pour immediately; reaction time is short.
• Leave expansion room in your mold or cavity to avoid overfilling.
• Use proper ventilation and personal protective equipment when mixing and pouring.

At Fiberglass Florida, we carry 2 lb, and 4 lb pour foams for marine, automotive, and construction projects. Shop pour foam here.