dense expanding foam to fill 20mm square section tubing 400mm long

[lfnfan]

Hi

I am looking for recommendations for a really dense expanding foam that I could use to fill lengths of 20mm square section tubing to a depth of 400mm.

Would also be grateful for advice on best method of application to ensure I reach the desired depth (and without getting expanding foam everywhere - I've never used it before).

Many thanks in advance

 

[opps]

A depth of 400mm? Do you mean length rather than depth?

I used to purchase the cans of expanding foam that had the nozzle included. One day, I purchased a gun to use with gun grade foam. The gun was a tenner, but it allowed me reduce the rate at which the foam was expelled. It really was a game changer.

I no longer buy expanding foam unless I additionally buy a can of (acetone) gun cleaner.

If you mist the areas to be filled, it will improve adhesion and speed up the curing times.

 

[lfnfan]

Hi @opps - thanks very much for your response. Really appreciate it.

Yes, sorry, 400mm length, not depth.

Interesting I had seen the gun variety but wasn't sure. That definitely sounds like the right way to go to avoid shooting the foam all over everywhere.

Are any foams more heavy / dense than others ,do you know? Or are they all basically the same substance made by different manufacturers?

Many thanks again!

 

[Deleted member 174758]

Are any foams more heavy / dense than others ,do you know? Or are they all basically the same substance made by different manufacturers?

The main difference between different construction foams is generally whether or not the foam is a low expansion foam or a standard expansion one. Low expansion foams tend to be used more for tasks such as fixing skirting board, plasterboards, etc as opposed to blocking gaps and holes. TBH in construction foams density isn't really the issue - all the foams we use are fairly low density. This is partly as a result of the foam cannister containing both the polyurethane material which will expand and set on contact with moisture in the air and a compressed gas propellant.

If you need a dense material you'd be better off looking at something like resin potting or casting compounds (electronics suppliers or modelling supplies respectively)

 

[lfnfan]

If you need a dense material you'd be better off looking at something like resin potting or casting compounds (electronics suppliers or modelling supplies respectively)

This is really interesting.

Truth is I don't know if I need dense or not. I have a whole bunch of dining chairs with hollow metal legs that make a proper racket scraping on the hard floor whenever we get up or sit down. After putting felt on the bottom of one chair legs, I don't think the issue is chair-floor scraping, it's chair-floor vibration, which happens even with the felt. So I'm thinking: fill the chair legs to damp the vibrations. I don't know if light or dense is better.... Cost-wise going foam+gun or resin/casting is going to be about the same.

 

[Tigercubrider]

You might be better packing the legs with some kind of felt lagging? Roll it into a tube and ram it in with a dowel?
The felt should deaden the sound, keeping the felt in one piece allows you to pull it out if it doesn’t work.

 

[lfnfan]

Nice one - thanks for the suggestion! I have a bunch of felt I can use to give it a go, so that's a low-cost thing to try.
I will report back!