Is there an art to using expanding foam
- Thread starter JP_
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just trim it off
you can get neater results by covering the surroundings with cling film, taped down at the edges. It is easily removed once set.
Spraying water into the hole will make the foam expand and skin faster, helping you gauge how much more to use.
You can also spray water onto any excess that bulges out, this makes it skin over so it will not stick so easily to whatever it touches.
If you have a deep hole to fill, you can tape over it tightly, punch a hole in the tape just enough for the injector tube, and then block the hole. Because the foam cannot expand out through the hole, it will expand into the cavity, filling it better. I got good results filling gaps round windows by drilling through the frame or a batten fixed over the gap; the foam had to expand into the gap. When you see it bulging out of the next hole above, you can be fairly sure it is filled up to that level. Trimming off the wart of foam that gets through the hole is easy, once set. You can inject into each side in turn to give the other time to expand.
Spraying water into the hole will make the foam expand and skin faster, helping you gauge how much more to use.
You can also spray water onto any excess that bulges out, this makes it skin over so it will not stick so easily to whatever it touches.
If you have a deep hole to fill, you can tape over it tightly, punch a hole in the tape just enough for the injector tube, and then block the hole. Because the foam cannot expand out through the hole, it will expand into the cavity, filling it better. I got good results filling gaps round windows by drilling through the frame or a batten fixed over the gap; the foam had to expand into the gap. When you see it bulging out of the next hole above, you can be fairly sure it is filled up to that level. Trimming off the wart of foam that gets through the hole is easy, once set. You can inject into each side in turn to give the other time to expand.
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gosh look at all those cracks the foam has caused
powerful foam ....
The house will get new render one day .... maybe next year!
If you find normal foam expands too much, try the 'exact' variety. You pump it in to fill the gap until you have enough in there. It will stop filling the gap when you stop pressing the nozzle on the can and won't keep on expanding.
I use exact foam on upvc window gaps between the frame and brickwork. This is because on larger frames normal expanding foam can expand too much and distort the upvc frame. The exact foam fills the gap and no more. Much neater too, with no trimming after.
I use Everbuild Exact Gap Foam from Toolstation.
I use exact foam on upvc window gaps between the frame and brickwork. This is because on larger frames normal expanding foam can expand too much and distort the upvc frame. The exact foam fills the gap and no more. Much neater too, with no trimming after.
I use Everbuild Exact Gap Foam from Toolstation.
After about 10-15 mins you can normally touch expanding foam depending on temp without it sticking to your fingers.
When its still soft but not sticky anymore you can manipulate it and push it back into the gaps it came out of without the need to wait until its fully cured and then trimming it back to carry on working.
When its still soft but not sticky anymore you can manipulate it and push it back into the gaps it came out of without the need to wait until its fully cured and then trimming it back to carry on working.
I've found this to happen with out of date cans, bought a case full cheaply before and the first one went in a similar way, right mess. Once I knew to expect it, then i was ready to use the lot in one go. Now I always buy a fresh can right before using it and never had the same trouble.
I would have thought the 'flammable' on the tin refers to the solvents/vapours inside, but generally the standard tins are flammable but you can buy fire retardant foam.
The standard ones are really flammable, especially when cured.
They light up like petrol.
For anything that needs to be fire resistant, use the pink foam which is fire resistant.
In any case, put very little, stand back and if you're thinking "i haven't put enough", it means that you have put too much already.
They light up like petrol.
For anything that needs to be fire resistant, use the pink foam which is fire resistant.
In any case, put very little, stand back and if you're thinking "i haven't put enough", it means that you have put too much already.
I find the 'gun' ones are more controllable, ie, less expansion of the foam and easier to control the foam. Downside is you have to buy a tin of cleaner so you've doubled up on the cost and no matter how well you think you've cleaned the gun through, after a dozen or so uses the gun becomes clogged.
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