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,