Foam-iT! 5 Rigid Polyurethane Foam expands significantly, up to about ten times its original volume, according to the manufacturer's description.
It's pretty versatile, so you can use it for things like prop making and filling gaps. This foam comes in a two-part system where you mix equal parts by volume, and once it's set, it has a density of about 5 pounds per cubic foot. It also becomes tack-free in roughly six minutes, which is handy if you're tackling creative or functional projects.
That said, our research shows that people have had different experiences with it. While the manufacturer talks up its expansion capacity, some folks found it only grew to about 1.5 times its thickness despite sticking to the recommended temperature and environmental conditions. This suggests that its expansion might depend quite a bit on specific conditions, like how accurately you're mixing it or the environment where it's used.
We also saw some variability in achieving the expected density, with results sometimes differing based on things like the shape or size of the mold or container you use during the curing process. These variations highlight how important it is to be precise with mixing and applying to get the results the manufacturer aims for.
To deal with these quirks, it might be a good idea to start with small test batches. That way, you can see how the foam behaves in your particular setting and make any needed adjustments to get the density and expansion you're after.
Folks who have some experience with projects like casting or prop building often find it effective for large models or reinforcing structures.
Just keep in mind that Foam-iT! 5 is rigid, so it's not suitable for stuff like making squishy toys or flexible items. If you need something flexible, you'll want to look elsewhere.
But if you pay close attention to how you mix and apply it, you can really make it work for your project.