Polyurethane foam in a spray can

Actually guys, after further reading of the threads on polyurethane foam and water logging woes, im much discuraged about the product .I may just go back to my original idea of using styrofoam sheeting, the blue or pink stuff .

 

Styrofoam is dissolved by gasoline etc...

When I was thinking about flotation I came across DOW Thermax.
It is closed cell gasoline proof insulation polyisocyanurate foam sheeting and comes in various thicknesses.

Look at table 4 to see how good this is compared to styrofoam
http://www.fabricationspecialties.com/pdf/thermaxwhite.pdf


http://msdssearch.dow.com/Published...fety/pdfs/noreg/233-00589.pdf&fromPage=GetDoc

 

Without the aluminum skins, it's useless.

 

Styrofoam and gasoline makes a pretty decent napam, turning the liquid gas into a putty like mixture to a thick liquid, not a very good soultion around areas where you may have spills.

PAR, the Great Stuff foam, as you said can push a door frame out of shape in a cavity, so it expands with some pressure, but I wonder what the outter skin that forms is like on the areas it is in contact with, does the surface that touches the surface (like wood) form the same protective surface or is that by the virtue of hitting the air?

 

I found that these spray foams are considered to be like solid gasoline by fire departments. Even during the application they can ignite due to the extreme heat that builds up due to the reaction.
Scroll to mid page to see the fires
http://www.tasconindustries.com/CelluloseVsFoam.html

I have never used these foams and likely never will. Seeing how dangerous they can be why take that risk.