22 replies to this topic

[Cooperman]

When doing a body restoration it can be a good idea to fill some 'blind' area with expanding gap-filler foam as obtainable from Home-Base and other DIY outlets.

 

The places worth doing include;

 

The enclosed areas at each end of the screen scuttle panel which can be accessed at the inner rear ends of each wing.

The ends of the rear valence, after drilling some holes at the bottom edge to let the foam out as it expands.

Around the jacking point by way of holes drilled in the inner sills.

 

It may be worth considering doing the bottoms of the rear side companion boxes beneath the liners to keep the rear quarter panels from corroding.

 

On a Mk.1 & 2 I've seen foam added at the lower screen level into the A-post void where it meets the A-panel and front wing. Sometimes there is a small gap around that area where water can get in from front wheel spray, but be careful in case the foam expands and pushes the outer panel surface outwards. I remember a friend who filled the new sills on his Triumph 2000 with this foam and he didn't put enough expansion holes in. It split the new sills from the body-shell!

 

Allow sufficient expansion holes, trim off the foam which projects from these holes after the foam sets and use a little bit of body filler to seal the holes off then paint over them with body colour.

 

Any way of keeping moisture out is good on a classic Mini. In fact I've just done one side of the '64 car I'm restoring.

 

[Quicksilver-ash]

If I bought a car that was full of expanding foam I'd be expecting bodges, I wouldn't recommend it

[lewBlew]

I guess this advice is more for people who have no intention of selling their classics and just want them to last.

[Dan]

  The first Mk1s had expanding PU foam filled sills and it was found to accelerate rusting.  The foam I think is non-absorbent but as the panels flex around it they break away from the surface leaving a tiny gap that fills with moisture by capillary action and this gets trapped there.  At least I think that's what was going on but modern foams will be vastly different and maybe it works better now.

[Cooperman]

As I said, it's a tip for people restoring their cars and wanting them to last and not rust again.

[Cooperman]

The reason the foam filled sills were discontinued on the very early cars was because if the sills had to be welded the foam gave off noxious fumes & vapours and, apparently, some guy in a body-shop ended up in a bad way due to this.

The modern foams are used in aerospace applications to increase the rigidity of some structures and to eliminate moisture ingress. Apparently they work very well. On a classic car with rust-prone almost enclosed structural voids a good modern expanding foam is absolutely ideal so long as there are sufficient expansion holes which can be sealed and painted over afterwards.

[OhDear]

there is a couple of types of foam  general foam expands eg. lets say x10  where as you can get a grip foam ( for plasterboard adhisive) which is like x2 say

 

My little advice

[Minilegs]

Thanks cooperman for this post. I'm currently restoring my mk1 which did have foam filled sills etc from the factory.

I have removed it all as it's a major restoration , and I have been trying to decide whether or not to refill them again. I think you have now made my mind up, foam back in just a more modern one 😃

[CityEPete]

Even if you are keeping the car repairs from accidents can still be required, sweating between the foam if not 100% sealed and water sneaking in tiny crevices is more than likely, id rather have cavity wax and rubber plugs put in to re apply regularly on a nice warm day, its not for me thanks.

[Vipernoir]

Waxoyl or Dinitrol for me - I've seen what happens to expanding foam when it gets old and wet, and it just crumbles.

[KernowCooper]

I injected all my Car with Ensis Fluid its the Rust Preventer they use on North Sea Oil Rigs, and it dont get much more agressive then that. Kernow Oil Hayle Cornwall will fix you up or tell you the agent in your area.

 

once sprayed its never hardens leaves a oily wax coating and rust preventer on the metal, it also creeps as well so excellent product but some know it and some of the restoration forums are aware of it.

Edited by KernowCooper, 10 January 2014 - 06:55 PM.

[Tamworthbay]

Bilt Hamber stuff all the way for me, developed by Peter Hamber who learnt his trade in the North Sea oil industry. Great stuff.

[Rog46]

If you filled the sills with foam what would happen to condensation running down the pillars? Wouldn't you need to fill these as well?

[Cooperman]

The foam I use is the same foam as I used to waterproof my garage workshop where it was leaking about 6 years ago. The foam has been subjected to really heavy rain-water and is still fine.

Anyway, that's what I do as well as Waxoyling everywhere and it seems to work. In particular at the ends of the screen scuttle panel it seems very good.

[Durknp]

what about this stuff. is it any good?

 

http://www.ebay.co.u...=item46186a7df7