Outer Limits 4x4 Board

Ok currently repairing my sills from dents etc and in doing so pulling out handfulls of damp mud from inside the sills (and the last time i used it was months ago) and there is a fair bit of rust around.

What do you think of putting that spray expanding foam stuff inside the sill once completed through a small hole.
This would then fill up the whole space and not allow any water/mud to enter the sills, and may also provide more strength/rigidity to the sill having a 'solid' center.

Any thoughts? Anyone tried it?

The moisture would get between the foam and the metal = more rust!!

my 2c

nickw86au wrote:The moisture would get between the foam and the metal = more rust!!

my 2c

not if the foam sticks to the metal!

Nick is right, it will make it worse and trap water

Most types of expanding foam are hydrophillic by nature. They absorb water and this will soon ruin the bond with the metal, leading to further rust.

If you are interested in making this work for you, you will need to steer clear of the "foam in a can" type products and look towards a closed cell urethane foam as used by boat builders for in-hull floatation.

These do not absorb water, nor do they allow water to penetrate between the foam cells.


Talk to your local boat supplies merchant or urethane supplier. You can purchase the type of foam you need in a 2pac liquid form, ready to be mixed and applied.

If you want to prevent it rusting you could spray it with fish oil in there. I haven't used it myself, but have heard good things about using fish oil in sills and bottoms of doors etc.
Obviously not going to strengthen it though.

Ben

i'd go for fish oil than having a foam filled sill.

make bigger holes so ya can hose'em out!

don't do it my last car had it on the left hand side and repairing of anything on that side was hell......not to mention that side had more rust than the right side......

thoroughly clean the car and allow to dry.......spray with fish oil and I mean heaps of fish oil and cover this with cavity wax to seal the seams covered in fish oil........allow about 3 weeks for the smell to die down...

James

Might sound stupid but would silicone do the trick?
Very flexable and doesn't shrink, water proof etc!

jtraf wrote:allow about 3 weeks for the smell to die down...

Plus some

But I reckon it _does_ work. I've done it on two cars and haven't had any rust issues despite going down to stockton semi-regularly. Pull the seats and flooring out while you're going, I caught a heap of rust under the sound deadener paint in my zook whilst doing it - treated it with rust converter, painted it (no bog, you can't see what's going on under it - just like that expanding foam stuff) and it hasn't come back since, despite it having been bad enough to create holes in my floor... I'd only just gotten it, too . I've sprayed fish oil all over the place and i reckon that's helped stop it from coming back.

You can get scented (or de-scented...?) fish oil that doesn't smell as bad from supacheap I think...

Nick

lol i think that the best solution to this problem is to just cut them off!!!! That is what i am doing and then going to run my sill protectors up the side where the sills used to be

You could use silicone, as long as its neutral cure and there are no gaps between the sills and checkerplating.
ie you have to make sure you put enough silicone

i once used that expanding foam to fill in and re-shape a rear quarter on an Escort P/van. It was rubbed back to bare metal before the foam was sprayed in and it never rusted in that spot again.

built4thrashing wrote:i once used that expanding foam to fill in and re-shape a rear quarter on an Escort P/van. It was rubbed back to bare metal before the foam was sprayed in and it never rusted in that spot again.

...because there was no metal visible

On a serious note - did you basically use that stuff as bog?... cause i've seen somone fill a hole (a dent) in with bog; a few years later the bog caused rust as the moisture was trapped between it and the metal, and the bog lifted itself out. I personally don't fill any holes, I'd just rather soak 'em with fish oil (or any similar product) cause otherwise you can't see the rust until it's too late...

chop it oFFFFFFFFFFFFF!!!!!!!!!!!!!!!!!!!

50/50 Fish oil and Sump oil in the sills.

Klappers wrote:chop it oFFFFFFFFFFFFF!!!!!!!!!!!!!!!!!!!

I have chopped it off but now i have to put something back for my WOF (inspection)... grr...

Thanks guys some interesting thoughts there...
So maybe spray a decent coating of fish oil in and then fill it with a closed cell foam

i just used it as fill and bogged over it. the bog ate into the foam a bit and it came up un-noticable