Adding water to expanding foam

[Mathew Newton]

I seem to be using expanding foam more and more ever since I bought a gun applicator now that I can actually control the stuff and don't need to use it all up in one session.

I always read instructions, but don't always follow them. One instruction is the warning not to overfill - I am slowly getting there on this one - but another is the recommendation to mist spray the surfaces and/or foam (if applying layers) with water. I wondered what the actual effect would be (I know; I should just try it) and stumbled across

which suggests it *really* does help - greater yield, faster cure and few voids.

Does anyone else do this?

[harry]

It's water makes the foam go off (Usually from the air) Also water improves adhesion (strangely)

So if injecting foam into a closed space, you need to spray a little water in first.

[Jim K..]

Yes.