I think I'm doomed with foam

[Andy Burns]

When I was using a lot of foam (replacing all windows/doors) I had a decent foam gun, and kept it cleaned after each usage, no problems.

Then when I started using it less frequently it started to get "gummed up" between uses, so I stripped it down, it was ok again for a bit, I tried leaving it with the foam can attached rather than stripping/cleaning, and that ended-up completely blocked, stripped it down again, and after the next time, gave up on the gun.

Instead I bought a hand-held can and a bunch of replacement nozzles, used it once, discarded nozzle, cleaned the spout of the can with acetone then left it stored upright, indoors.

Just came to use some a couple of months later, went to shake the can and "uh-oh that feels almost solid" gave it a vigorous shake anyway, didn't really do any good, attach nozzle but when pressed down not even a dribble would come out.

So it becomes expensive to use in small quantities ...

[Brian Gaff]

Hang on, surely it should not go solid as the pressure is pushing out not sucking air in, unless the cleaning of the nozzle made it leak the propellant out and the air then got in. Sounds like that could be dangerous as it expands and might then presumably burst out of the can. Brian

[Andy Burns]

In the past, I've thought storing a part-used can inverted might be better, as the gas couldn't leak out without it being noticeable, but apparently storing upright is the correct way.

some foam (probably dissolved by acetone to make a thin "glue" before the acetone evaporated had created a seal around the nozzle on the can, I had to press it firmly to break that.

The can isn't under any extreme of pressure, it has some give when gripping it firmly, the contents aren't fully solid, but it seems there's a "plug" of cured foam above the liquid and whatever gas remains.

[tabbypurr]

A nail should free it then ;)

NT

[Tricky Dicky]

And foam everywhere if it does.

Richard

[tabbypurr]

shhhhh

[Iggy]

replying to Andy Burns, Iggy wrote: Don't clean nor take anything apart and let a big blob seal off the end of the nozzle/tube. When you need it again, in the same day or week, then cut the blob off with a bit of nozzle/tube. If it's months later, then you'll need to replace the nozzle/tube...I've had success with this for a can up a year old.

[Andy Burns]

The instructions recommend finishing the can off within one hour!

[Iggy]

replying to Andy Burns, Iggy wrote: I'm sure they do. But, the stuff won't cure unless exposed to air. Treat it like caulk, mustard, plasterboard compound or glue and it'll stay viable.

[harry]

The foam is expelled by means of gas. The gas leaks out over time so the cans have a shelf life. Buy them when you need them. There are various sizes.

The foam sets by means of atmospheric moisture, so it won't set in the can. If gas is lost, you just get a gummy liquid out. Good as a glue but no foam.