Using foam gap filler in frame?

[Jpat34721]

What do y’all think about filling your TJ frame with expandable foam to keep out salt, dirt and water to prevent rust? Any downside to this?

 

[TJ4Jim]

What do y’all think about filling your TJ frame with expandable foam to keep out salt, dirt and water to prevent rust? Any downside to this?

I think it would be too easy to trap moisture and could accelerate rust.

 

[Zorba]

NO! It'll just exacerbate the problem.

 

[BlueC]

Any downside to this?

That's a terrible idea. No upside, all down. Those foams are generally open cell and are virtually a sponge which hold water. Even if you used closed cell foam, it would create voids and pockets that would trap dirt and moisture. You can see this in many houses if you look around. Lots of rot damage is caused by spray foams.

 

[Artsifrtsi]

It would undoubtably act like a sponge. I have seen where idiots used it for body repairs, and it holds everything you are trying to exclude, and just dissolves the metal at an accelerated rate.

 

[P man]

Absolutely not

 

[Chris]

Sounds like one hell of a stupid idea

 

[Shank]

https://wranglertjforum.com/threads/filling-the-frame-with-expanding-insulating-foam.27081/

 

[BlueC]

Sounds like one hell of a stupid idea

So Chris, who's burner account is it? Is it Boogie? He's always talking about rust, and new wives, and biden... I'm pretty sure bad idea fits in there somewhere.

 

[Zorba]

Perhaps someone should ask ChatGPT...

 

[P man]

So Chris, who's burner account is it? Is it Boogie? He's always talking about rust, and new wives, and biden... I'm pretty sure bad idea fits in there somewhere.

I dont think it's a joke I have seen this come up a few times over the years

 

[roverhi]

Had a fuel tank bedded in poured foam on a boat. Of course the tank leaked. When I pulled the tank the bottom against the foam had completely disappeared because of corrosion.

 

[BlueC]

Had a fuel tank bedded in poured foam on a boat.

Lots of smaller boats, I think it's 29' and under, with the required flotation foam have significant rot issues after a decade or so. Rotten transoms and soft spots in the floor are common due to the moisture held by the foams, even though closed cell is used.

 

[Steel City 06]

Some OEMs will do this to stiffen car bodies and cut down on noise. However, they use a 2-part closed cell low pressure foam, usually with a relatively high density. Very different than insulating foam.

 

[BlueC]

Some OEMs will do this to stiffen car bodies and cut down on noise. However, they use a 2-part closed cell low pressure foam, usually with a relatively high density. Very different than insulating foam.

Are the bodies also coated/dipped before applying the foam?

 

[LONGJP2]

The factory foam didn't help the rockers on my '04 Grand Cherokee. It rusted out there first.

 

[srimes]

Spray foam is strangely popular with meth heads. You don't want people thinking you use meth.
Instead, fill the frame with quickcrete. Much stronger.

 

[L J]

What do y’all think about filling your TJ frame with expandable foam to keep out salt, dirt and water to prevent rust? Any downside to this?

clean the frame out and use Eastwood's internal frame coating:

https://www.eastwood.com/eastwood-internal-frame-coating-14oz-aerosol.html

 

[Steel City 06]

Are the bodies also coated/dipped before applying the foam?

It depends. Usually it is only done in unibody vehicles, or in the body only of a body-on-frame vehicle. So the exposure to salt spray is less than a typical frame sees.

Generally there is some sort of coating, or the foam mixture has a low enough viscosity to flow into every crevice and act as a sealant by itself.

 

[Rut Row]

a closed cell foam might work. Closed cell foams do not absorb water.