Expanding Foam - great stuff?

[Sir Percy]

Hi,

I'm going to fit some slabs of insulation (Celotex/Kingspan etc), and plan to cut them to fit loosely, filling the gaps around the edge with expanding foam.
I expected the brands available to be much of a muchness, but have come across this:
Dow Great Stuff
http://www.wickes.co.uk/Wickes-Expanding-Foam-Filler-750ml/p/109746
which seems to be a lot more expensive than others, and straw, not gun grade.

Just makes me think, is there a difference in the foams available that I need to be considering?

Cheers

 

[MikeJhn]

If this insulation is going in between roof rafters you need a gun and gun grade foam, trying it without is a really messy, there is not much difference between various makes as its the exclusion of moving air that is the main insulation in any void, the substrata of the insulation mediums are much the same.

Mike

 

[Sir Percy]

If this insulation is going in between roof rafters you need a gun and gun grade foam, trying it without is a really messy, there is not much difference between various makes as its the exclusion of moving air that is the main insulation in any void, the substrata of the insulation mediums are much the same.

Mike

Not quite roof rafters, but similar. Will check out other brands of gun grade foam, thanks.

 

[MikeJhn]

Don't forget to cost in the gun and the essential gun cleaner.

Mike

 

[RobinBHM]

I found cutting the celetex accurately and then push in place the best method.

Mark the exact size on the foam then cut to the line but use a tapering cut, which allows the piece to push in nice and snuggly. Use the gun foam for sealing around awkward shapes that cant be cut easily in the celetex.

I found cutting loosely and using foam not very good.

 

[Lons]

What Robin said, it's much easier to cut the celotex accurately and slightly tapered than fill with foam later. I fitted over a 100 8 x 4 sheets that way on a stable conversion without problem, used a very sharp old carving knife and straight edge.
If you do use foam just get the cheapest you can as there's little difference in the canned stuff but as Mike said it's much better to use gun grade if using a quantity.

 

[MikeJhn]

Cheapest I'v found @ £2.87 inc VAT : http://www.powertools2u.co.uk//Expandin ... 0wodpDcC2A

Mike

 

[MrDavidRoberts]

Yes there is a huge difference in expanding foams- as in how much volume you actually get out of the bottle.
I have tested like 5-6 different ones (mainly because I find it really expensive and just searching for alternatives...)
and by far the best one has to be this one from TS , Don't believe what they write on the bottle about how much you can get out of 1 can , each brand differs a lot when you actually come to use it
http://www.toolstation.com/shop/p27912? ... panding%20

+ much cheaper than your wickes as well.

 

[Lons]

Yes there is a huge difference in expanding foams- as in how much volume you actually get out of the bottle.
I have tested like 5-6 different ones (mainly because I find it really expensive and just searching for alternatives...)
and by far the best one has to be this one from TS , Don't believe what they write on the bottle about how much you can get out of 1 can , each brand differs a lot when you actually come to use it
http://www.toolstation.com/shop/p27912? ... panding%20

+ much cheaper than your wickes as well.

I've used that one and it's been fine but can't agree with

"there is a huge difference in expanding foams-"

I've used just about every brand of the canned stuff in my building business over the years and very little difference as far as I found between brands in as much as it all does the job. Quite rightly there is a variation in how much you get out of a tin but you're just as likely to get that using only one brand, it's pot luck whether a good tin or a bad and none of it keeps very well either.

One difference I did find though was the quality of the nozzle mechanism. By far the best method is gun grade however!

 

[MikeJhn]

Agree with Lons, practically no difference between brands, but It also makes a difference at what temperature you are operating in and how well you have shaken the container, they need at least a few minutes of agitation to allow the whole thing to discharge.

Shop around for a good deal, I got two boxes of Soudal foam for a very good price and free delivery, you just need to perceiver when looking around.

I would not use anything other than a gun to dispense it, makes a huge difference.

Mike

 

[MrDavidRoberts]

heh you must be totally blind not to see the difference in amount you can get out of each brands can
The liquid volume is the same, but to how large volume it expands after its out of the can is totally different for the cheap Vs expensive ones..
The more expensive brands are much better value as they just hold more stuff + dry faster/ application nozzles are better etc, but it gets to a point where paying too much diminishes the value for money.

 

[MikeJhn]

And that is your considered opinion. :roll:

Mike

 

[Lons]

I'm less polite than Mike and after 20 years running a business where I used a great deal of the stuff I'd say your considered opinion is misinformed bull****.
You can take several cans from the same manufacturer and batch and get different volumes out of all of them. Whether you believe it or not I've used most of the brands available and having just looked have cans from Unibond, Jewsons and Screwfix on a shelf at the minute. The Unibond was 3 times the price of the others and absolutely no better.

It's your money fella and if you want to waste it by paying twice as much as necessary that's your business but I'm certainly not blind. Maybe you should do a test using a few hundred cans to prove your expertise on the subject.

 

[Bm101]

Straying a little bit off topic... interesting point about the brand vs price... do you tend to find the same for mastics, fillers, basically gunned stuff overall? I'm not talking about specialist stuff like pipe sealant for large scale boilers in big buildings etc but run of the mill caulk, mastics etc. I have often wondered if the trade ones are any different from the big brands. I tend to get a lot of stuff like this from my local builder centre types for my house. I tend to avoid the big diy sheds if possible as the pricing doesn't make sense to me generally though they compete well on certain products. For a time I bought the branded names but for the last few years have bought the cheaper variants and I have to say I have seen no difference in finish or longevity at all. Be interested what you guys who do it day in day out think.

Tbh I tend to think of it like buying branded Neurofen of Aldis Ibuprofen these days. Do the same job but one is a hell of a lot cheaper than the other, costs go on branding. I'm sure there's certain products that earn their price tag but I'm not sure how many of the rest do. Interesting to hear what you all think.

Back on topic I worked on a house renovation many years back now and the roofer used a hot wire contraption to cut cellotex. No idea how it worked but he had it set up on a jobbed up contraption. It was very efficient (think table saw efficiency) but I'm guessing hes in a bit of a 2 and 8 now 'cos he wore no mask and he was breathing that in all the time. Who knows.
Cheers.
Chris

 

[Simou1]

I'm less polite than Mike and after 20 years running a business where I used a great deal of the stuff I'd say your considered opinion is misinformed bull****.
You can take several cans from the same manufacturer and batch and get different volumes out of all of them. Whether you believe it or not I've used most of the brands available and having just looked have cans from Unibond, Jewsons and Screwfix on a shelf at the minute. The Unibond was 3 times the price of the others and absolutely no better.

It's your money fella and if you want to waste it by paying twice as much as necessary that's your business but I'm certainly not blind. Maybe you should do a test using a few hundred cans to prove your expertise on the subject.

Not so much misinformed bovine exretia, but total bolleaux. Used foam for many years here and in Germany and have never noticed any difference between the so called premium brands and the Screwfix/OBI/Hornbach own brand equivalents. What does matter is application using a quality gun and an appropriate cleaner. The actual volume of foam out of the can depends on ambient temperature, sufficient shaking, shelf life of the product and the quantity of propellant. Never ever known the next can to be the same as the last; they all vary.

As for sealants/mastics and fillers I cannot see much of a difference either though I did use Sikaflex to mount a sat dome and a solar panel on the roof of my motorhome and find Everbuild's Stixall to be a superb product. The rest I buy from Screwfix (own brand) or look out for the excellent offers on Amazon which are delivered next day.

 

[MikeJhn]

=D> =D> =D>

Mike

 

[Sir Percy]

...
Back on topic I worked on a house renovation many years back now and the roofer used a hot wire contraption to cut cellotex. No idea how it worked but he had it set up on a jobbed up contraption. It was very efficient (think table saw efficiency) but I'm guessing hes in a bit of a 2 and 8 now 'cos he wore no mask and he was breathing that in all the time. Who knows.
Cheers.
Chris

Not quite on topic, but I remember back in the '70s my mum coming back from the Ideal Home exhibition with a 'craft gadget' which was a basically a wire strung between two arms and a handle, connected to a big old battery like you'd run your Scalextric off. It was supposedly for artfully sculpting polystyrene. The fumes! Gak!

Anyway, fwiw I ended up with the Siroflex.

 

[MikeJhn]

I used to use one of those hot wire bows to cut foam wing cores, it was not easy when the wing had a taper and the speed of cut was critical to ensure no dips or burning of the foam core, those where the days. 8)

Mike

 

[Simou1]

Crickey, fond (I think) memories of building model railway layouts with my sons out of foam. As we were in Germany at the time, we bought a Proxxon foam cutter not too dissimilar to the one Amazon sells

http://www.axminster.co.uk/proxxon-12-e ... 0wodY0oHQQ

It was remarkably effective but the foam did emit a smell when melted and you had to move sharpish to separate the cut bits as they could re-weld together nano seconds after the 'cutting' action.

We built some fabulous layouts with Fleischman and Marklin trains climbing mountains resembling those in their film of the moment, 'Where Eagles Dare'!