Theory for protecting frame against rust

[Tungsten]

Good old frame rust. Anybody that lives up in the salt belt knows all about it. Salt makes the metal on the frame oxidize (or rust) much quicker than it will normally. An oil coating can protect the frame but it doesn't necessarily go everywhere. Recently I have been looking at boats and they come with these interesting strips of zinc attached to them called zinc anodes. Apparently when metals like iron suck up zinc, they will not corrode. Galvanized frames have a coating of zinc on them so they corrode on the surface by reacting with the metal underneath and prevent the frame from corroding. Zinc can be effective in feeding iron when submerged either in water or in oxygen. The best part of all is that you really need to do is just make electrical contact between iron and zinc. So my theory is that by bolting a block of solid zinc to the frame you are effectively galvanizing it and protecting it against any corrosion. Sounds almost too good to be true but I am going to try it and stop by a local marine place and stick zinc blocks to my frame. Maybe it will survive salty winters for much longer.

[ahardb0dy]

I think you are thinking about Cathodic Protection, we use it at work to protect our larger water mains,

 

http://en.wikipedia.org/wiki/Cathodic_protection

[Tungsten]

That's it. If it works in industrial applications then why not cars and trucks?

[3rdtimesacharm]

One issue here is protecting the whole of the car. I hear thats not such a concern on marine applications due to it being generrally wet out there and the charge uses that to its advantage.

 

Applying zinc blocks might help directly where its touching the metal but then it could also just be an area for moisture and salt to get trapped.

 

Hard work, a zinc primer and a decent over coat is probably the best solution..

[nunya]

you have to factor in that the underside of any vehicle is not constantly submerged all its life and those rust inhibiting factors are being sprayed against it. As well one of the wd21 issues is it's boxed frame that traps it's own demise within itself and mixed with clogged drains which tend to be overlooked by many which speed the process. Keep the outside of it coated with some form of rust preventive paint (which I am due for a fresh sanding and coating personally), keep your drains clear, and rinse out your frame regularly There's a bunch of access holes all along each rail that make this a little time consuming but not a challenging task

[AzZo]

Yea,Rust never sleeps.Must be on a constant watch or else!! It will creep up on you I also live in the salt belt and my pathy needs serious grinding on frame rails and welding and recoating with a good rustproof primer and paint.

[Alkorahil]

I have heard of this rust stuff on frames.

(sarcasm)

 

 

There are many ways to help prevent it, some noted here, even spray on rust prohibitor and undercarriage sprays, but washing the salt off periodically is the best solution really.

Edited November 24, 2012 by Alkorahil

[Tungsten]

You don't need submersion in water for it to work. Zinc is sacrificial even in the presence of oxygen. Theoretically even welding some zinc wire along the frame rails should prevent the frame from rusting. Salt is only a catalyst to rust. The frame will still rust even in non salt belt states only much slower. The reaction with oxygen or water is what makes rust hence the name oxidizing.

[Precise1]

The frame will still rust even in non salt belt states only much slower

Yes, by an order of magnitude or two. So slowly as a matter of fact, they look rust free...

 

B

[Slartibartfast]

Can't be too hard to test. Best way I can think of is to take two identical steel plates, stick a piece of zinc (the outside coating of an alkaline battery should do) to one, then hang them both from the transmission crossmember over the winter. Check them in the spring, and if they're still there, see which is oxidized worse.

[Tungsten]

That's actually a really fun idea. I'm going to try it.