Midyear bumper rust on the inside....

[Patrick T.]

I have a beautiful set of rechromed bumpers on my '67. Lately however, I have been getting concerned on the accumulation of rust on the inside of the bumpers. No, you can't really see it, but rust never sleeps.

My question is, how can I attenuate this situation or should I? Should I leave them as is, in the open air, or apply some kind of rust preventative? I'm not sure if sealing the inside surfaces would drive the rust through to the outside chrome. I thought about cathodic protection for the bumpers but that's out since I can't wire the bumpers with sacrifical anodes, without it being detected. Do we have any corrosion engineers here?

Thanks in advance for any suggestions. Patrick

[Mike M.]

Re: Midyear bumper rust on the inside....

not a corrosion engineer(didn't know such critters existed) but this ole hillbilly uses Neversieze to coat the inside of freshly re-plated bumpers. gives them the as new factory appearance. ya just gotta hope the judges don't finger the insides as you'll be detected.

[Geoff C.]

Re: Midyear bumper rust on the inside....

I would suggest trying Merde Cream. Smells like crap, but it supposedly does wonders for what you need.

[Eugene B.]

Re: Midyear bumper rust on the inside....

Gentlemen,
What do you think of using a product like Rust Converter or Extend. It states that it "turns rust to a blackish primer"? I used it on the backside of my '65 bumpers and to me it looks pretty good. At least, it will not come off on your hands like Neversieze will.

Regards,
Gene

[Patrick T.]

Re: Midyear bumper rust on the inside....

Mike and Gene, I do have a can of Loctite Extend rust neutralizer which I could use, it's for existing rust. I am not familiar with Neverseize. Another reason I'm concerned about sealing the rusted area is that a couple years ago, I bought a pair of new '57 cresent bumperettes at Carlisle.

When I got them home, I washed them with soap and hot water, let them dry in the sun and then applied a coat of chrome wax on both the inside and outside. Wrapped them up in newspaper and then into a box and stored them in my closet for a year or two. When I finally opened them up, the outside chrome was full of red rust dots, so bad that I had to have them rechromed.

[Mike M.]

Re: Midyear bumper rust on the inside....

Pat: i believe chrome polish is hygroscopic(attracts H2O) I've had friends who did the same thing with waxes or pastes and it didn't protect from oxidation. As far as Never Sieze goes, its a coating thats sold as a rust preventative. Its a very greasy based material that will prevent a coated bolt immersed for years in salt water to stay rust-free--at keast that's the advertising gimmick the company used l5 years or so ago when i became acquainted with the product.Bostic makes it. Loctite and permatex make similiar anti-seize compounds. lately i've switched to the loctite variety as it is easier to remove from my hands and various parts i coat and yet don't want the judges observing my attempts at rust prevention( the loctite is white and wipes off enough so that ists nearly undetedtable whereas the gray never seize is nearly impossible to remove from hands or vet parts) mike

[Chuck S.]

Re: Midyear bumper rust on the inside....

Patrick, one of the methods of corrosion engineers is coatings.

I believe I would try POR15 which stops rust by excluding air. One of their "Super Starter Kits" would probably be enough to do your bumpers. It comes in gloss clear which would give you a permanent rust prevention coating that would reveal the original semi-plated appearance (or raw steel depending on the condition), and it won't transfer or rub off. Bumpers don't get much plating on the backside...that's why you have the rust.

A couple of cautions: (1) The prep solution is phosphoric acid based and it will attack and maybe remove any remaining chrome plating residue. If this is a concern for you, I believe I would try it first in a limited area to see how it affects the finish on the backside. Also, BE VERY CAREFUL in applying the prep solution. Use a small brush carefully with the outside masked with plastic film...if it gets on the outside surface, it may damage the chrome finish. One option would be to just skip the prep solution altogether and mechanically clean the surface; you may sacrifice a little adhesion for safety.

(2) POR15 is not UV resistant. It may get some UV exposure on the backside of the bumpers, but probably not a lot. It would last a pretty long time, but for a PERMANENT (as long as the grass grows and the rivers flow) solution, you would have to top coat the POR15 with one of their UV resistant top coats.

[Patrick T.]

Re: Midyear bumper rust on the inside....

Chuck, how are you doing Amigo? Long time, no see! Clear POR 15 sounds like some good stuff for a permanent fix, but I would be afraid to use the acid prep for fear of getting it on the nice chrome. I put acid on my VIN pad once to clean it up and the pad started smoking! I will check it out on an old bumper first.

Mike, I always keep a couple tubes of Loctite antiseize compound, which I use on every nut and bolt on the car. Never thought about using it inside the bumpers, but it is silver and relatively harmless, and it will come off your hands, although it will stain black paint. If I don't like it, I can easily take it off.

As Chuck mentioned, since he is a pipeline engineer, there is a such discipline called corrosion engineering. They are the guys that constantly monitor and maintain such structures as the Trancontinental Oil Pipeline (Transco) and the Columbia Natural Gas pipeline, both of which are high pressure steel and run from Louisiana up to Canada. The Alaskan oil pipeline is the same. Corrosion is of a BIG concern here, cause when one of those baby's blows up, and they do once in a while, there is a major liability situation to deal with.

[Chuck S.]

Re: Midyear bumper rust on the inside....

Some variety of high temperature (aluminum or copper based) "never-seize" is, in my opinion, an absolute necessity for changing sparkplugs in a late model Corvette with aluminum heads. My choice was a silver, aluminum based product made by Wurth.

Install dry steel spark plugs in aluminum heads at your peril...next time you change'em, you'll possibly remove the aluminum threads with your plugs. Never happened to me, but I did experience a little abnormal resistance the first time I changed plugs (pray, go slow, and hope it comes out without significant damage to the threads). I was lucky until I got smart.