Great Stuff under pressure?

[Vincenzo]

I want to insert a piece of pipe in a fitting in the pilot of my 2" piston valve, and fill around it with Great Stuff. I am just not sure if it will be able to withstand the pressure? I will be using a max of 120 psi.

[Hotwired]

Helps if you tell us what it is.

I've checked and the most likely product seems to be insulation foam in a can...

No.

That isn't going to hold 120psi. A proper reducer/bushing is needed. You don't want to make the back of a 2" valve out of something you can poke your finger through.

[jackssmirkingrevenge]

That isn't going to hold 120psi. A proper reducer/bushing is needed. You don't want to make the back of a 2" valve out of something you can poke your finger through.

Unless he's just using it to fill dead volume and not as a stressed structural component, in which case it should be reasonably adequate at those pressures.

[ramses]

Even to fill dead volume, it could be compressed. Any closed cells in the foam may fatigue and rupture. Then the foam would store air, but only absorb/release it slowly. Something like this I use caulk in my hybrid to fill dead volume, and it seems to work fine.

[Vincenzo]

On second thought, how about plaster of paris? There won't be any force on it and I'd coat the top of it with something else... Should I take a pic to show you guys what I'm trying to do?

[Selador]

I want to insert a piece of pipe in a fitting in the pilot of my 2" piston valve, and fill around it with Great Stuff. I am just not sure if it will be able to withstand the pressure? I will be using a max of 120 psi.

Use the foam in the way that you wish.

But then cut away some of it, and fill the void left, with epoxy.

On second thought, how about plaster of paris? There won't be any force on it and I'd coat the top of it with something else... Should I take a pic to show you guys what I'm trying to do?

The foam is going to make for a lighter weight piston.

Yes, take the picture.

[saefroch]

I wouldn't recommend using great stuff on a spudgun, as it is quite a flimsy material. As a general rule for myself, I say if it's ghetto, it's a bad idea. It does however make for a pretty good target. Picture would help with suggestions of alternate materials.

[Fnord]

If in doubt, bondo.



It's cheap and fairly tough.