Fighting Corrosion with Zinc Blocks

[crashz]

This is not tractor related, but close. This referes to my 1 ton dump truck.

My truck was used to plow and salt roads and parking lots for many years. The body has been completely replaced about two years ago, and while it is starting to corrode a little, its not too bad. The frame and suspension of the truck is very corroded though. When I bought the truck this past May, I inspected it closely and found only one weak spot in the frame. I had that fixed by a certified welder, and all is good. My quest now is to remove as much rust as possible, seal and paint the frame, and possibly prevent any further corrosion using dissimilar metals.

Zinc blocks have been used in marine environments from ship hulls to steel peirs and also in the natural gas industry along steel pipelines. I'd like to use this technology to protect the frame of my truck from any further corrosion with small replacable blocks of zinc bolted directly to the frame. Somewhere in my chemistry notes, I have the calculations for influence area affected by sacrificial metals, so I'll be able to figure out spacing and sizing.

I can't seem to find a source for the zinc though. Has anyone done something like this before? Where do I find the materials? And does anyone have a better method of rust prevention?

 

[YotaBota]

Hmmmm. Interesting idea with the zinc blocks. Cool idea. There's been alot of hype about zinc lately, so it might be difficult as a private individual to latch onto zinc blocks. I would suggest using POR 15 or Rust Bullet to coat your metal.

 

[/pine]

Just about any commercial marine supply outlet should have just about any shape and size zincs...

 

[crashz]

Can't beat ths site for info!

I came back to this thread to read it and found a link to an online marine supply store! Ordered two large peices for the rear section of the frame and 8 smaller pieces that I'll distrubute evenly from front to back.

Before I do that, I need to spend a few days wire brushing the frame, painting and finally grinding clean spots to mount the zinc annodes. My initial thought is to have the two large blocks centered on the outside of the web of the frame just forward of the spring hangers. The small blocks will be installed on the inside of the of the frame in a similar manner with three forward and one behind the larger blocks.

As I work on this I'll continue to update this thread. But be patient, 'cause I don't plan on working on the truck until after April 16th. Thats the day of my PE exam.

Thanks!
Leo

 

[Diamondpilot]

The guys are right about the zinc blocks being available from marine supply business. Make sure you have the area where the block is mounted cleaned up good, use anti-seize, and good stainless hardware.

Chris

 

[Cruisin]

Sorry, zinc blocks won't help much unless the truck frame is going to be underwater like the lower unit of an outboard motor or ship's hull. The zinc is a sacrificial anode. It's eaten up by the galvanic corrosion that occurs when dissimilar metals are immersed in an electrolyte of some kind. It's is more active than steel or aluminum so it goes first. If bolting on zinc blocks would stop the rust, they'd never paint a steel bridge.
You can use a zinc based primer and paint.

 

[MMagis]

Cruisin is right, zinc blocks aren’t going to keep your truck from rusting. Hope you didn’t spend too much.

 

[20 20]

I'll 3rd the bad news. The zinc blocks used on ships etc. work because they are covered in salt water. On a vehicle they're not going to do anything except add weight.

 

[caliver68]

I bought a motorhome a few years ago that was rusted very bad on and under the frame. The previous owner kept it near the ocean. I sand blasted. Then sprayed it with a product called Salt-X. Then coated it with anti-rust stuff.

 

[JC-jetro]

You do need a solution (salt) in order to complete the circuit. You can put zinc on your truck and chassis and submerge the truck in salt water and it'll work. Don't reckon you would want to do that. Zinc as sacrificial anode is used quite often to protect underground piping (Passive cathodic Protection) for years, and moist soil act as the conductive solution.

JC,

 

[RoyJackson]

Yep, zinc blocks on a seagoing vessel are sacrificial anodes...but to work, they need an electrolytic bath (salt water).

 

[gerard]

They do have plug in electric systems that put a charge on the whole body. You have to plug it in for it to work. Won't work when your driving but if you can plug it in when parked it would help. Not sure how effective they are but the physics says it would work.

 

[DarrylH20]

Yep, zinc blocks on a seagoing vessel are sacrificial anodes...but to work, they need an electrolytic bath (salt water).

I see hes from New England. The way they salt the roads up here he will be in a eletrolytic bath

 

[Tractor Parts]

The anode of the ships wills corrode and deposit on the ship's propeller. If the anodes were not there, as a result of dissimilar metal corrosion, the propeller would corrode and deposit on the ship's hull. Thus, the zinc was used as a cheaper alternative, rather than replacing the very expensive stainless steel propeller.

However, the concept is fine. There are devices that are being sold that continuously keeps a very small current running through the body of cars/vans etc. As per the "region of corrosion" (a term in metallurgy), the small current will prevent the metal body from excessive rusting. It's called the "No CounterAct Electronic Rust Protection System." You can see the description here No CounterAct Electronic Rust Protection System

Its actually specially designed for snow removal trucks.
regards
Marlon
Caterpillar Alternator

 

[some zilch]

the best way to stop/slow down vehicle rusting is to wire brush/sandblast the frame, and use something like POR-15, or even a good primer/then paint. i have 4 dodges, all former municipal vehicles, all carried salters, and all plowed roads their entire life before me. i know about rusty trucks. salt is an evil, evil, material.

 

[JC-jetro]

the small current will prevent the metal body from excessive rusting. It's called the "No CounterAct Electronic Rust Protection System.
Marlon
Caterpillar Alternator

That is also called "impressed Current Cathodic Protection". I have used it on underground gas piping system before. Many gas companies use that till they convert their metal underground piping to Plastic (cross linked Poly Ethylene" .

JC,

 

[Egon]

However, the concept is fine. There are devices that are being sold that continuously keeps a very small current running through the body of cars/vans etc. As per the "region of corrosion" (a term in metallurgy), the small current will prevent the metal body from excessive rusting. It's called the "No CounterAct Electronic Rust Protection System." You can see the description here No CounterAct Electronic Rust Protection System

In Canada it may be illegal to sell these devices???

http://www.bushman.cc/pdf/corrosion_theory.pdf

A site giving some explanations for corrosion.

 

[alchemysa]

I bought one of these 'Electronic Rust Protection' systems once as I was considering retailing them. (Although it wasn't the particular brand mentioned above). I set up a simple test, with two pieces of thin sheet metal side by side mounted on a plastic board. Each piece of metal was about 6" x 6". I sanded each piece with grit paper to remove any surface film. One piece was then wired to the system, the other was not. Occasionally I sprayed a bit of salt water on both to accelerate the rusting. After about 2 months the surface rusting was identical on both pieces and 'the system' appeared to have provided no benefits whatsover even on such a small piece of metal. My conclusion was that it was useless.

Regarding using zinc anode blocks, I think its possible that they would be beneficial even on a truck, although they would only work when the truck was damp.. and its my experience (living in salty air) that cars and tracks are damp very often.

 

[Skyco]

Whenever I want to absolutely have no corrosion on something I use a "cold galvanizing" paint. Works very well. This stuff is used to touch up hot dip galvanized communications towers and seems to do the job.
There are a number of brands on the market.

 

[crashz]

Darryl hit it on the nose.

The truck is parked on gravel in a enclosed building. All summer is had condensation on the frame. Anytime its taken out into the rain, through puddle, etc., the back od the truck gets soaked since its wide open to the dual wheels. With the amount of moisture that is seen by the frame (especially in the back) I tend to think that this may work to a degree. From late fall through spring, our vehicles are immmersed in a nice brine of NaCl, CACl, PoCl as ice and snow control, so when soaked, this system will theoretically work.

I also agree that a strong barrier type coating and a nice thick coat of frame paint is the primary protection. I've started the frame cleaning this past summer and used a rust converter (forms a tough epoxy like coating) on the outside of the frame. I've also liberaly coated the underbody with Fluid Film (FF) and will continue that each year. I plan on using the heavier wax flim that FF markets for the frame and chassis.

Fortunately, the zinc blocks didn't cost much (~$50) and I think its worth it if it works at all. If it doesn't work, pretend you never saw this thread...