On Sun, 18 Jul 2010 18:26:13 +0100, John Rumm
wrote:

two guns would be sensible if using two different types
of foam regularly.

I had a can of "normal" foam that I found had expired in June. I used
this up and replaced it with a new can of the same foam and there was
a difference: the fresh foam came out much faster and expanded more.
I'm not sure whether that was an advantage or a disadvantage but there
is obviously some deterioration with age.

Near the end of the can of old foam, I could hear that there was
something left when I shook the can but it just squirted "air" out of
the nozzle when I tried to use it. I am sure it was not air but
something far more poisonous. What would it be: butane? Is that the
propellant?

When I unscrewed the empty can, foam leaked out the can-end of the
gun. Does this mean the valve in the gun is faulty? The trigger was
locked closed so it shouldn't have leaked, should it? And why was
there foam in the gun considering it was only spraying gas out the
other end?

I bought a third can, this time of the adhesive foam, and a new gun,
to fix my celotex with. I think I did this partly for the novelty: I
had never used this foam before. It occurred to me afterwards, why
didn't I use a grab adhesive like gripfill, no more nails, etc. I
wonder whether they would have been less messy? Is there an advantage
to using the foam? the only thing I can think of is that it is easy to
cover large areas. I wonder whether a tube of something would have had
more initial grip? I think that might be my fault though, because I
think you are supposed to apply the foam and wait for it to go tacky
before pushing into place.

I used all this glue foam up in one day and when that was empty, it
was empty and it came off the gun completely clean too, so I think
there must have been a problem with either the other can or other gun
or both.

When using the gun cleaner spray to clean up the gun, I saw it
contained acetone. I never expected that. I thought it was cellulose
thinners, I don't know why. You used to be able to buy small bottles
of acetone from the chemist. I wonder if they have been banned now? if
not, it might be worth getting one for cleaning of wet foam.

Thanks.