Just insulated over the rafters with insulation boards and filling any gaps with foam but seem to be spending rather a lot of time trying to unblock foam guns. Onto my third one now. I leave the canister of foam on if not finished and put something over the end. When finished I clean out with gun cleaner and have disassembled the nozzle, pin and poke the ball bearing valve to make sure not blocked but still can't get them to work. Any tips would be much appreciated!

My method is, once finished:

1) Take the can off. Can be messy.
2) Spray cleaner where the can connects until it's visually clean
3) Put the cleaner in the gun, open regulator fully
4) Trigger the gun until the foam stops coming out and then it's just cleaner coming out
5) Take the cleaner off, last spray around
6) Close the regulator
7) Put the foam can on, nice and tight ready to use again

Thanks for the tips.

Gravelld,

You say:

1) Take the can off. Can be messy.

7) Put the foam can on, nice and tight ready to use again


are you suggesting there is a valve in the can, then? There did not seem to be when I took a can off too early and effectively decorated the room (including a Chinese silk lampshade) with foam until the can was empty.

My experience is that taking the can off when not in use and spraying the foam cleaner inside is the worst thing to cause blockages. It might work a couple of times, but eventually you'll leave it just that bit too long, and the foam will start to set.

I've used tonnes of the stuff, many different guns and the best luck I've had is as Mike George said. Keep the cannister on until it is empty, and always screw closed the valve on the back to shut it off after use. When you need to change cannisters, do it immediately. Don't leave the gun exposed to air with all the foam inside it.

I've tried taking a gun apart, and it's pretty much impossible without damaging it, so once it's gunked, it's junked.

Even doing it Mike George's way, and I've done it religiously, some guns still managed to seize. I think it's an inbuilt flaw that forces you to buy more foam and more guns, but I certainly wouldn't waste time with the cleaner.

Maybe a better quality gun has better seals.

Posted By: JT101When you need to change cannisters, do it immediately. Don't leave the gun exposed to air with all the foam inside it.

Yes - I should have said that. foam begins to cure very quickly

Just a gentle reminder to you foam users. The fumes are inflammable. Responsible for the Glasgow School of Art fire. And now this: http://www.standard.co.uk/news/london/fireball-engulfs-builders-arm-as-he-uses-foam-to-plug-mouse-holes-10079536.html

100% with All of Mike George notes.

I tried the other way, with cleaner and thoroughness. did not work. I now have a gun per type of foam.
I have left one gun unused for many months and come back to use it. All good
If i lend the gun to anyone/let them use it, first thing I do is check the that regulator is screwed up.
Sometimes when taking cans off they have a life of there own. still plenty of foam, even though its not coming out via gun. As soon as a the nozzle from the top of the can gets stuck to gun, the gun is a write off.
I tried all metal guns and guns with just metal nozzle. No difference.

Cleaning foam from clothing : my approach has been slow attrition. Minor scrape of foam before a wash, wash item, then another minor scrape. Its just gets into everything. If its gets on me, leave for a few days as per glues and minor attacks on it when gets to annoy me .

Posted By: gravelldI'm just using the screwfix products (gun and foam)

Prob as gd as any - rebadged Soudal.

Posted By: alexc
I have left one gun unused for many months and come back to use it. All good

Same here. I eventually killed one by leaving it for over a year on a very nearly empty can.

Posted By: alexcAs soon as a the nozzle from the top of the can gets stuck to gun, the gun is a write off.

Come to think of it, that's just what happened with the dead gun when I came to take the last can off.

Can anyone recommend a decent foam gun?

My cheap screwfix one is kaput

Thanks

yes... the guns are very simple, the 'seal' is a brass nipple at the end with a tapered pin pushed home onto the internal machined female cone.
Unscrew the adjustment knob at the back, remove keeper spring, grip rod with molegrips, rotate and 'unscrew'.
The pin/rod will have debris stuck to it, that need to be wire-wool-removed, but be careful where the pin enters the tube 'chamber' by the trigger... laborious but can resurrect a dead gun.

... not yet

I have tried cheap and pricey. The way I use it seems to have more influence on it getting gummed up or not. Leave it on the can for regular use or give it a darn good clear out with cleaner and leave it on the cleaner can if left for longer periods.

I've got one of these. Came free with a box of foam. Works fine for me (first time foam user).

https://www.uksealants.co.uk/concept-pu-expanding-foam-gun.html

There are obviously more expensive models. But the main think is that it regulates the foam output in a controlled and adjustable manner.