Expanding foam test

[Wightsparks]

This came up recently on here about using expanding foam to prevent rust. many have said that it just absorbs water and promotes rust. Personally I am not sure, so test. Cleaned and abraded plate, 2 dobs of Everbuild fire rated foam in fetching pink. One cut one left sealed. Left outside on my boat next to the sea....



Will see what's underneath in a while..

Might try some box section if I can find some handy...

 

[123hotchef]

how long is a while

 

[Keith 66]

Well every boat i ever worked on that had expanding foam in it was a soggy mess full of rot, I can think of nothing less suited to keep rust at bay.

 

[Mark 2]

how long is a while

I have it on good authority that it's longer than a bit.

 

[Wightsparks]

how long is a while

Probably until I need the bit of steel for something else..

 

[Farside]

Well every boat i ever worked on that had expanding foam in it was a soggy mess full of rot, I can think of nothing less suited to keep rust at bay.

Leyland found that when they filled the Mini sills with foam. The foam lost its adhesion to the steel and created a capillary water path, just lovely for salt-laden moisture to creep along.

 

[Tupers]

Leyland found that when they filled the Mini sills with foam. The foam lost its adhesion to the steel and created a capillary water path, just lovely for salt-laden moisture to creep along.

Great fun when you go to weld your now rotten sills as well.

 

[Burdekin]

It’s an open cell foam.

We had some closed cell foam around a vessel a good few years back and wasn’t supposed to absorb water but did. We weighed it and then heated it up, water got in but steam didn’t get out and eventually exploded, didn’t expect that.

 

[Screwdriver]

This came up recently on here about using expanding foam to prevent rust. many have said that it just absorbs water and promotes rust. Personally I am not sure, so test. Cleaned and abraded plate, 2 dobs of Everbuild fire rated foam in fetching pink. One cut one left sealed. Left outside on my boat next to the sea....

View attachment 204500

Will see what's underneath in a while..

Might try some box section if I can find some handy...

Excellent. A practical real world experiment. I like that approach.

My assumption; it will actively promote rust due to the water retention and permeability. Over the course of even one year, there will also be noticeable UV degradation. The surfaces will effectively turn to dust and mulch.

This is one of the big problems with plastics IN the oceans. If they were floating on the surface, they would break down quickly under UV bombardment but because they sink they persist. Plastic waste in our ocean will be the death of this ecology unless we fix the problem very quickly. At the very leat, we should stop our manufactured waste products from being unceremoniously dumped into the seas in such gigantic volumes. Yes China and India, I am looking at you...

 

[Wightsparks]

Next time I open a can I will do the same with Instastik - which is a low volume foam that is an incredibly strong adhesive. If the issue is with water entering the foam/metal interface then that stuff will likely show better results.

 

[earthman]

Excellent. A practical real world experiment. I like that approach.

Me too, and by a totally independent person I assume.

Anyone seen the XCP stand at trade shows etc? It's all very well him having that board with bits of metal on, comparing ACF-50 and the like but the test weren't done by an independent body/lab, that doesn't give me much faith in the product to be honest.

 

[Wightsparks]

@brewdexta ran a rust coating test a few years back https://www.mig-welding.co.uk/forum/threads/corrosion-prevention-product-test.78045/

 

[earthman]

I like the brake disk, leave it outside for a few months test.

 

[Burdekin]

Also try putting them in water, weigh them before and after and then leave them to see if they dry out or just hold the water.

Insulated piping and vessels keep me in a job, corrosion under insulation is our biggest corrosion issue in the oil and gas industry. Mineral wool even use to leach chlorides when wet, just to make it even more exciting.:-) We’ve spent millions and millions stripping insulation, inspecting and fixing pipes and vessels. This year alone we’ve found a load at the terminal and hence prevented gas leaks.

What I would say is don’t put expandable foam anywhere you might get corrosion and then have to fix at a later date, you will regret it if you do.

 

[Wightsparks]

I like the brake disk, leave it outside for a few months test.

Interesting experiment - but totally unnecessary foul language.

 

[colnerov]

Leyland found that when they filled the Mini sills with foam. The foam lost its adhesion to the steel and created a capillary water path, just lovely for salt-laden moisture to creep along.

Ditto with Rootes and the Hillman Imp!!

 

[Dcal]

Ditto with Rootes and the Hillman Imp!!

Ditto with Alfa and the Alfasud.
Evil stuff when you have to repair it (and you will as it soaks up the water) I still remember the fumes from over 20 years ago.

 

[stuvy]

Vauxhall experimented with filling the A, B etc pillars with expanding foam to add crash strength was back in the viva days

 

[500e]

Only ever done it on comp cars to add stiffness that worked but life of the shell was fairly short so rust not a problem, had other problems as expanding foam was fairly new & we did not really understand it. It was stronger than a lot of spot welds & even some of the metal
Water was not a problem, we cut up some shells & founds stess cracks in foam which could have led to capillary problems if longer life was the the object.

 

[cheb]

A stationary test is one thing. But what are the effects of constant flexing going to do to the foam's matrix?

The foam's expansion is powerful enough to burst boat decks from the hull too, as I've seen people find out the unfortunate way.