Bicycle Mechanics - Combatting Rust on a CroMo Steel Frame

Hey, I have an 80s Fuji Roubaix with a steel frame that has accumulated its fair share of dings over the years, especially on the underside of the downtube (from contact with rectangular bike racks for years) and I was wondering - Is there a product I can apply to prevent rust on exposed steel areas where the paint has been scratched and to prevent the rust from spreading? Is this even a valid concern?

Is there a product I can apply to prevent rust on exposed steel areas where the paint has been scratched and to prevent the rust from spreading?
There sure is. It's called "paint". :rolleyes:

Seriously, there are commercial preparations that will remove the rust and treat the bare metal to inhibit further rusting. Naval Jelly is one brand but there are others. Then use touchup paint to cover the bare spots.

Ospho on the rust, then touch up the paint

Would you guys actually worry about it? None of the rust spots are very large at present. Is it an impending problem, or would I do better to just leave it alone? Thanks for the quick responses!

I've heard periodic application of linseed oil can inhibit the spread of rust. Anyone confirm / deny?

I just stripped a 70's steel frame because it had some rust spots showing through a few places. Upon removing the paint in the area of the rust, there were spider web like trails of rust running far away 6" to 10" from the original rust spot and running under what appeared to be good paint.

You have to chemically kill the rust (naval jelly, extend etc. ) so it doesn't continue to spread.

knotty

Would you guys actually worry about it? None of the rust spots are very large at present. Is it an impending problem, or would I do better to just leave it alone? Thanks for the quick responses!
I certainly wouldn't ignore it. The spots you see are small but, as knotty said, rust can undercut the paint where you can't see it. It sounds like your bike was stored outside for quite a while so I'd definitely pursue this further. Consider stripping the frame completely, treating it and just giving it a rattle-can paint job unless it's worth a professional paint job to you.

I've heard periodic application of linseed oil can inhibit the spread of rust. Anyone confirm / deny?

Pretty much anything that blocks water's access to the metal will prevent rust. The reaction requires water. It also need to be continually present ie not washed away.

I used to do body work on cars as a hobby and found the best stuff ever in the world to combat rust and provide a nice surface to work with. The stuff is called POR-15. It's a thick black liquid that brushes directly on to rusted surface, neutralizes it, then chemicaly seals the area, further preventing rust, all the while leaving the area with a nice, smooth, semi-gloss surface to paint upon, or just leave as is. I have tried all the brush/spray/acids(naval jelly) rust converters and nothing comes close. The coolest thing is, no elbow grease. You spray on some degreaser(they have a recommended one of course, but i use simple green), then brush/roll it on bare rusty metal and come back the next day, and its damn near bulletproof. The magic of it is is that its a moisture cured coating, not a solvent based paint, so the more humidity in the air the better. If i sound like i am selling it, that's because I am, and today only at this special... Seriously, if i had the money, i would buy everyone this stuff for their stocking, becuase it works fantastic. drawbacks... the price is higher than most, and I can't ever find it locally, so you have to pay shipping on top of it. The good news is that for bikes, a pint/quart should last forever. Last one is a minor inconvenience. If it gets on your skin, make your peace with it cause it'll be there for a few weeks, That being said, this stuff, although industrial doesn't have hardly any of the nasties that come with solvent/acid stuff. I wouldn't drink it or bathe in it, but other than that, pretty harmless. I just revisited the site and looks like they have some new things that i can't wait to try, like a high gloss clear coat made out of the same stuff, and some different colors. I always just used black, and that even looks nice, Especially if its on beloved commuter/tourer/utility that you would hate to lose to cancer. Alright sorry about the book, but some things a person feels strongly about, and this is one of them for me. really, try it. they have a starter kit that you can buy, but 1 quart and you'll be sold... Thanks for listening, Frank


Damn, almost forgot... www.por15.com

You know...that sure sounds familiar...almost verbatim as a matter of fact.

That said, the stuff is supposed to work but is also supposed to be fairly toxic. For bikes I would use something a bit less 'industrial' but maybe that's just me.

Frank - isn't the clear POR-15 basically just super glue (isocyanate)? Also - you don't remove the rust when you apply the POR-15, you just paint it over the de-greased top of the rusty area?

If that's the case, couldn't I just simple green the areas and super glue over the top of them? The areas are small - only a few millimeters in diameter. Thanks for the tip!

im not a chemical engineer, but there is a clear difference. The main one being that your digits wont get stuck together,and it doesnt ball up like super glue, it flows like paint, dries hard as hell, and you can sand/prime/paint on it.The MSDS is listed on the site so take a look, but this has fewer warnings than super glue. Now,for all i know you could have a shaman bless your ride with chicken blood and that may do a better job, but i gave my personal, average joe,rust-haters opinion. Until somebody else can chime in and back me up, then you just gotta take the red pill,Neo(or was it the blue one). Anyway, best of luck to you all, whatever method you choose.

Can't vouch for it personally but have heard of people using it on their prized steel frames: Weigle's Frame Saver

Can't vouch for it personally but have heard of people using it on their prized steel frames: Weigle's Frame Saver

I just have to ask - is frame saver really necessary? Good insurance? Piece of mind?

I used boiled linseed oil thinned with mineral spirits for better flow. I pour it into an empty lighter fluid container because the little spout allows me to get it into the tiny holes in the stays and fork.

POR-15 is certainly the thing to use on the rust. We use it on old British cars to save them all the time.

Thanks for all of the help - I ended up sanding down the offending areas and putting a few coats of rustoleum clear enamel, but I have some POR-15 on the way for a cruiser that I'm restoring that has a little more rust than my Fuji did.