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🛠️ Float, fill, and fortify—foam that means business!
Fiberglass Supply Depot’s 4 lb density expanding pour foam is a two-part polyurethane closed-cell liquid foam designed for rapid curing and superior buoyancy. Perfect for boat and dock flotation, soundproofing, insulation, and filling voids, this quart kit produces 1/2 cubic foot of waterproof, sandable, and paintable foam that bonds with common resins without melting. Engineered for professionals seeking precision and durability in demanding environments.










| ASIN | B08T255GS5 |
| Best Sellers Rank | #31,363 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #69 in Urethane Adhesives |
| Brand | Fiberglass Supply Depot |
| Brand Name | Fiberglass Supply Depot |
| Color | Black, Clear, Yellow |
| Compatible Material | Vinyl |
| Container Type | Bottle |
| Customer Reviews | 4.4 out of 5 stars 126 Reviews |
| Full Cure Time | 5 Minutes |
| Item Form | Liquid |
| Item Package Quantity | 1 |
| Manufacturer | Fiberglass Supply Depot Inc. |
| Material | Foam , Resin |
| Material Type | Foam,Resin |
| Package Information | Bottle |
| UPC | 819794022897 |
| Unit Count | 64.0 Ounce |
| Viscosity | Medium to High Viscosity |
| Volume | 1 Quarts |
| Water Resistance Level | Waterproof |
C**S
2part foam
The foam is exactly what I needed. It worked perfectly. Awesome product.
T**S
Expands quickly
I created a rear wing which was hollow and needed to strong as it is active and used as an air brake so I needed to fill it with foam. The 4 pound foam was perfect but calculating the internal volume was difficult. To be sure I wasn't going to come up short I added a little extra and did two pours. Because of the shape I couldn't see where the first ended so I proceeded to do the second pour. As soon as I saw it I had like 2 seconds before it over flowed. All good as I planned for this and could just cut the excess off. So be warned and prepared if you mixed too much. It sticks to everything and there is no stopping it. My wing now is as hard as a rock and strong so it worked well for me.
J**.
Great product! Directions a bit off.
This works great and made a nice, firm filler that I needed for a place on my kayak. It was easily sand-able and paintable. It is firmer/stiffer than the spray foam you buy in cans at the home improvement store. Just be aware that the directions are a bit off. In the video we watched online, it looked as if it foamed up instantly, and the directions said to count a number of seconds and no more before pouring. Our experience was that it took a bit longer for it to foam up, and we wasted some that poured through some holes in the cavity we were trying to fill. I would say an extra 10-15 seconds would have worked better.
R**O
Right product
Good product
J**.
Taxidermy work
Used for taxidermy purposes. It's a denser foam that does not expand as much as the lighter weight foams, but it has been great for form alterations etc Might be a waste to use for habitat work as you'd get more expansion from the lighter weights.
W**O
Good stuff!
Follow the instructions and work quickly. The foam pours easily after mixing and expands rapidly. Worked perfectly to fill and seal a baseboard area of my pole barn. Best I can tell, the estimated volumes are accurate.
M**T
Solidifies and foams up in a span on 8 seconds
Instructions were unclear and also we're not included so I started off slow poured some in at equal amounts of both solutions with nothing happening so I poured more started to mix and get thick but still barely forming so I figured I'd put all of it into a four gallon bucket started to see it mix more turned around for about ten seconds to prep the area on the wall to fill and I turn back around and it's all just a solid bucket of useless hard unmailable foam no choice at this point but to throw it all away wouldn't recommend if you plan to shape it in any way shape or form
R**D
Works as described!
I purchased this product to secure a fuel tank in a boat. It worked perfectly. I carefully followed the instructions, adding part A to part B (not the other way around), working in an ambient temperature of about 70 degrees Fahrenheit. It expanded slowly over a few minutes and did not "explode" as described by others. The instructions emphasize the mixing order, and I suspect that is the key to avoiding disaster.
Trustpilot
3 weeks ago
1 week ago