How to slow/stop rust under fenders

[Triley41395]

Just curious what most do to the underside of your fenders. I'd like to try and stop the rust under my fenders so that they might last another 50 years. I could sandblast and paint, use undercoating, I know POR is pretty good stuff. Aside from re-chroming what do most of you do. I'm thinking just sand and throw some primer on them.

 

[Skipp]

Chrome or powder coat are the two that I do…

 

[Mr. Pink]

I'm thinking spray on undercoating would work well.

 

[2old2care]

For a low buck approach, just sand, prime with Rustoleum red rust primer, and paint with some enamel - If you wanted to keep stones, etc from wearing the paint, then add some rubberized undercoat, or bed liner stuff, to that. But paint first, to get the rust fixed, if you want the undercoat to stick.

You can also kill the rust without harming the top chrome, by using an oxalic acid bath - This really works - I have done it.
https://bmxmuseum.com/forums/viewtopic.php?id=351132

You can also use citric acid:
https://bmxmuseum.com/forums/viewtopic.php?id=121049

If you remove rust from chrome with acid, you'll need to use a good wax on it at a minimum, and keep it out of the weather, or the rust will return.

 

[Strigoi]

An electrolysis tank would get rid of the rust and then you could just paint it. I'm not sure if that would ruin the chrome that's on it though. Electrolysis works awesome for getting rid of rust.

 

[Doc1976]

What condition is the chrome on the top side? If it's worthy of using as it is, I would media blast and undercoat or use a bedliner product.

 

[Triley41395]

I think I'm gonna try a combination of a couple of these. I have to find out first if powder coating heat will hurt the top chrome. If not I think I will blast and powder coat followed by some rubberized under coating for noise reducing. I'm only going to do this to the underside, I would like to keep the top chrome.
Thank you all for the input.

 

[Bird Brain]

Spray flex seal coating underside after removing as much rust as possible. Protects and dampens rock chipping would be my thinking. Powder coat option is good to when done correctly. Its Tuff stuff.

 

[manchester1]

I like to keep things original. Remove rust with evapororust. Under the fender I use WD40.

 

[manchester1]

 

[Triley41395]

View attachment 291317

That came out really nice. I am going to try and leave the top original chrome but it's a bit worse than I thought. I did clean the underside with 0000 steel wool, taped off the top and primed them,I had planned on undercoating them before I reassemble the bike. When I removed the tape alot of the chrome came with it. It's just kind of flaking off. Not sure what I'm going to do now if anything. I didn't want to power coat the tops but I might paint them now, still undecided.

 

[manchester1]

Soak in evaporust and lots of wax.

 

[manchester1]

 

[manchester1]

 

[Triley41395]

Soak in evaporust and lots of wax.

It's hard to get a good picture of how bubbly it is,but they look like this all over. They do look decent from a few feet away.

 

[manchester1]

I'm a original person so removing rust and keeping it original is my game. I wouldn't worry about the lumps. They are only original once.