Expanding Polyurethane Foam - Release Agent

I want to squirt some expanding polyurethane foam into a section of mdf box cladding covering some copper water pipes to cut down on draughts (an insects) from getting into the kitchen. Since I want to be able to remove the cladding if necesssary, what can I use as a release agent to prevent the foam from sticking to the inside of the cladding? The stuff seems to stick quite firmly to prety much anything.

I'll remove the section of cladding before applying the foam, but then replace it before the foam has set, to get a reasonable seal between the two.

Reply to
Davidm
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Line the piece of cladding with cling film may work?

Reply to
ss

I think I would go for slightly thicker polythene sheet (in one piece). Were you planning to let it mould over the pipes too? Does it matter if it sticks to the MDF, so long as the MDF and foam come off as one piece?

Reply to
newshound

It won't stick to polyethylene film, as such. Wrinkles and folds will hold the film on the foam. Just leave the film in place. Beware: one hole, and you will bond everything together.

Also:

If someone would remind me how to upload photos to the Wiki, I could do that...

Thomas Prufer

Reply to
Thomas Prufer

Thicker polythene (than clingfilm) and a quick blast of pledge before putting the foam in would be my choice if I really didn't want it to stick to stuff that was already there. Be aware that the expanding stuff is very keen on expanding and if it can't get out from a space througha hole will deform whatever it is inside making it bulge .

Reply to
Martin Brown

Also the solvent in it will melt some plastics...

Reply to
John Rumm

Once logged in, click on the "Upload File" link on the left.

To display your photo on a page just include:

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Reply to
John Rumm

Butter? Might pong a bit after a while though! How about lining the area with cling film or something similar before you squirt? Brian

Reply to
Brian Gaff

It needs to go around the back of the pipes, so don't want it to stick to the cladding. Cooking foil might be an alternative (comments about cling film dissolving noted).

It says on the can that it's ok to use on electric cables, but is it really (if it will dissolve some plastics)? Might have to put something over the cables.

Reply to
Davidm

Test it on some spare cable. My instinct is that it won't touch PVC at all but will dissolve/destroy expanded polystyrene very quickly indeed.

Reply to
Martin Brown

Sounds like a recipe for damage. The trouble with these expanding foams is they set solid THEN they expand forcefully in all directions.

NT

Reply to
tabbypurr

The foam needs moisture to expand and set. So it won't work. You can spray some water into the void before the foam but the results aren't very neat. Boats/cavity walls etc use two component stuff you have to mix. In practice it's mixed in the spray gun at the nozzle.

Reply to
harry

Would a dense wool type of thing not do a similar job?

Reply to
RayL12

try dried PVA

ISTR that is used at least for polyester resin

Obviously test first.

Reply to
The Natural Philosopher

My recent experience with a one part x50 expanding foam from a gun was that the resulting foam wasn't particularly dense or strong and I guess that further expansion would have been contained if the former was reasonably stiff and was securely fastened down.

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I will admit that I could see where all the foam was going and I did have a few test squirts to see how much it would expand.

Don't the one part expanding foams come in different expansion versions?

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Reply to
alan_m

they must, the last ones I used expanded with some serious force.

NT

Reply to
tabbypurr

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