2 Lb Polyurethane Expanding Foam
Adding or replacing flotation in a small boat? This 2 lb two-part pour foam fills under seats, inside bow and stern compartments, and other empty spaces with rigid, closed-cell foam that helps keep a holed boat from sinking right away. It uses a hydrofluoro-olefin (HFO) blowing agent.
How much do you need?
Here's the rule of thumb: one quart of mixed foam expands to about one cubic foot, up to about 30 times its liquid volume. Measure the cavity in cubic feet and you know roughly how many quarts of mixed foam to plan for. For best physical properties, pour to a core in-place density of at least 2.5 lb/ft³ (free-rise is about 2.0–2.2 lb/ft³).
- 2 quarts: 1 quart of Part A + 1 quart of Part B (2 quarts total), for small voids and repairs
- 2 gallons: 1 gallon of Part A + 1 gallon of Part B (2 gallons total), for mid-size flotation jobs
- 10 gallons: 5 gallons of Part A + 5 gallons of Part B (10 gallons total), for full-boat or shop quantities
Each cubic foot of cured foam provides approximately 70 lb of flotation. Every size includes both Part A and Part B.
What you get in the boat
- Stays dry: approx. 97.7% closed cells; water absorption 1.15%.
- Strong enough: compressive strength 31 psi; initial thermal resistance 6.1 R per inch.
- Bonds in place: sticks to fiberglass, wood and metal.
- Fuel-tolerant: it's petroleum resistant.
- Approved: meets U.S. Coast Guard 33 CFR 183.114 for flotation material.
- Finishable: cut, sand or paint it after it cures.
Pouring tips
- Mix Part A and Part B 1:1 by volume.
- Work fast. At 20 °C (hand mix): cream 25–30 seconds, gel 155–180 seconds, tack-free 250–290 seconds — pour in manageable batches.
- Use the foam within its 12-month shelf life.
It's not just for boats. You can also use it for flotation, caulking and insulation in vehicles and homes.
Data sheets
Related
- 12 lb expanding foam: the denser option
- All 2-part expanding foam
- Mixing containers and sticks
