Thread: Rust in 110's

but aint they aluminium ??
so how do they rust ??
is this Defender doors also ??
Thanks
Regards Adrian

Originally Posted by Defender=1st

but aint they aluminium ??
so how do they rust ??
Thanks
Regards Adrian

coz they are steel?

the door frames are steel, the firewall is steel... and galvanic corrosion doesn't help either with the mix of metals.

There's a bit of confusion between rust and corrosion.

Steel rusts, aluminium corrodes.

Where aluminium and steel connect (eg. door frames and body panels) corrosion accelerates. Not sure of the exact physics of it (others can tell you) just take it as gospel that it does.

I have some small amount of bubbling corrosion on my door body panels down near the bottom of the door. I took it to my local panel beater who advised me it would be cheaper and easier to be on the lookout for a secondhand set of doors that were rust-free and in reasonable nick. He could then paint them up, I could fish oil / lanolin / rust proof them and swap them over when ready.

In the meantime he recommended scraping off the rust / corrosion and just using some touch-up paint with some fish oil or lanolin to protect the door as long as possible.

... which is why I am trying to find the right paint code for my Blue '94 300tdi Defender 110 Station Wagon

Aluminium corrodes with a non-water-permeable oxide. "Annodised aluminium" cookware has been force-corroded to protect the base metal. Bolting steel onto aluminium creates a small battery (when exposed to water) which reproduces the annodising process and forces the aluminium to corrode. Note that in theory this protects the steel, though not in practice The galvanic corrosion of the aluminium doesn't result in "annodised aluminium" panels due to the thinness of the panels, instead it can corrode the panel right through.

Adrian, there's very little aluminium in the body of a Defender (or County, Or Series Land-Rover). It's just the cladding and rivets. Everything else is mild steel.

Mine is rusting under the heater box, on the door frame under the lower hinge and surface rust above the vents other than that its all good.

Plan on stripping down at Christmas time for a repair.

The age-old problem with the composite steel and aluminium construction used on these beasts is that the two dissimilar metals work like a battery when they are wet (more so with salt water) so you have electrolytic corrosion as well as good old fashioned rust. It is easy to prevent by using simple insulating barriers like polythene sheet and sealant but LR seem to be a bit hit and miss about using this preventative. Plenty of lanolin spray and CRC Soft Seal or the like goes a long way to slowing it down.

God you lot don't know real rust. Any defender i have seen in Aus (and disco and rangie for that ) has had in my terms (and what i am used to ) no rust at all. Just look under my 90 and then under my Disco. Both same age and the 90 had the chassis stripped back and redone 4 years ago and now it is alot worse underneth than the Disco.
I keep winding up my brother than my 95 disco has less rust under than his 2002 D2.

Originally Posted by Grizzly_Adams

There's a bit of confusion between rust and corrosion.

Steel rusts, aluminium corrodes.

If we are being pedantic - corrosion is a term that applies to ALL metals which oxidise - including steel.

Rust, as stated - is something intended to apply only to steel (or ferrous metals).

Galvanising (zinc coating) protects steel because zinc has a lower electode potential than steel - so it corrodes preferentially. This also means that zinc coatings still protect if there is bare steel. Tin on the other hand, has a higher electrode potential, which is why the steel of a tin can will corrode if scratched, rather than the tin coating. Aluminium has a lower electrode potential than zinc and steel, which means it also corrodes preferentially if the 2 are in direct contact.

I saw a seminar a few months back by a visiting professor, who said that biological corrosion (corrosion by microbes) is a much bigger factor than people think.