Cleaning and painting rusty steel frame
 

I got some cheap old rusty steel frame that I want to restore but I don't want to spend much on it. There's no paint left. I can remove external rust with sandpaper as it's not that deep but I would also need to clean internal tubes somehow. I was into few methods like dremel or some drill attachments but I'm not sure if they are going to work, perhaps there's something better than that? Next, I need to protect those internal tubes from rust somehow, I know there are many ways of doing so but I don't want to spend much as frame ain't worth the work so I'd like to ask what to use. Finally, what to use for external paint. I could get some crappy anti-rust paint and just do it, pour some into internal tubes and then brush few coats externally, then use some normal color paint on top of it. It would be cheap but probably not really strong but I see no other alternative, except for real lead paint that I actually got(not completely illegal here) but I'm not sure if possible risks are worth of it.

There are chemicals that will "freeze" rust in place, effectively converting the rust to a stable state. Evapo Rust https://evapo-rust.com/ is one. Or coat the insides with a rust inhibitor like Frame Saver. As to the exterior expect the rust to return in the tight spots. Maybe you can find a sandblaster to dust the otherwise already cleaned frame for you before any primer/paint is applied. Andy

As Andrew said I have had good results with Evapo Rust.

Search 'Removing Rust With Electrolysis'. I've done that with large antique car parts. When 'done' pour acetone or lacquer thinner into the tubes to wash away remaining water, dry using compressed air and repeat a few times. Pour linseed oil (Waxoil or similar) into the frame, plug the holes then rotate the frame to different orientations to coat the insides. When satisfied let the excess coating drain out. Re-clean the outside and prep for paint!

...the cheapest treatment for rust internally is to immerse the frame and fork for a couple of days in a solution of Oxalic acid, that they sell as "wood bleach" in most paint and hardware places. (I can buy it at Home Depot here.) I don't recommend it in your case, because it's much more hazardous to use than something like Evapo-Rust, and you need to neutralize it before disposal. Also it's absorbed throught the skin, and can crystallize in the kidneys with bad results.

But it's useful if you're doing a bunch of bikes at once, or can leave it outside somewhere to reuse a number of times in a tank you can cover.

You can get by with lesser quantities of Evapo-Rust by closing off all the holes in the frame except one (like the seat tube), then filling the frame with the stuff and letting it sit for a few days in warmer weather.

Thanks for answers. I know that Evapo Rust and Frame Saver are great things, but to get enough to cover whole frame would probably exceed the value of frame itself. I don't have tools and containers for electrolysis, but Oxalic acid sounds pretty good. From what I know I should mix powder acid and warm water in 1:10 ratio, then pour it inside frame and wait for around 12 hours, then dilute the acid with mix of water and baking soda and clean the remaining with just water. Am I correct here?

Now, speaking of paint I am unsure what to use, I've heard that 2-ingredient epoxy paint with hardener or 2-ingredient reactive paint with hardener are best primers but those are pricy compared to some anti-rust/corrosion 2in1/3in1/"paint and forget" solutions. Are those mixed paints really that bad, because everywhere where I look people disdain them. Also, would pouring some of such pain inside frame work as anti-corrosion cover? As noted above, I could try linseed oil for that but boiled version also costs alot here. Perhaps linseed varnish would work, I could get it cheaply.

Finally, what about that lead paint which I could get. It's relatively cheap and I could mix it with linseed varnish to create nice priming solution like they did 70 years ago but is it worth possible health hazards?

You can get what is called Industrial Rust Eliminator. I ordered a batch that can make 10 gals, From your neck of the woods. Works best if you keep the solution warm during the process, I have various size metal trays i put on top of the woodheater, so I try to do my rust removals during winter time.

Including shipping it works out to about a third of the price of Evapo Rust, damn sight cheaper.. and does the same job

I'm yet to figure out how to soak a whole frame though, i have one in mind.

If you would like to pursue electrolysis make your container from plywood or cardboard then line with polyethylene plastic sheet. The 'container' doesn't even need a bottom for the ground will suffice. You will need some way to keep the bike frame from poking holes in the plastic. My car parts held scrap lumber down easily enough. You could even treat sections of your frame piecemeal in a smaller home made container. I used my car battery charger as the power source and hardware store steel music wire as the sacrificial electrodes... you'll go through a few!

This works great and no rubbing/sanding required. Just connect everything then let it work for you!

Disclaimer: plug into a GFC (ground fault circuit) and use caution. Electricity can cause harm or death.
@le mans- make a container as outlined above!

...please do not do this with oxalic acid solution. The idea when using the stuff is to do it outside, and to handle the frame as little as possible, to minimize your skin and breathing exposure to the oxalic acid. So some kind of kid's wading pool with oxalic deep enough to submerge the frame is how most people do it.......outside somewhere.

If you're going to the trouble of plugging all the holes to fill the frame with a rust removal solution, it does not take very much solution at all. So in that case Evapo Rust ( which you can save and reuse a number of times), in the small container from Home Depot is your best bet. There's also the plastic bag method, where you put enough of it to cover your frame in a havy duty plastic bag and use some sand bags on the outside to move the stuff around so it fills and surrounds the frame.


If you go with oxalic acid, wear heavy duty rubber gloves, and it does have some fumes that are probably bad for you.

Thanks again. I am also wondering about electrolysis, I could use thick plastic foil and car battery charger or maybe old 9V cellphone charger. Just wondering is 9V enough and for how long should I keep it turned on. I guess it partially depends on type of rust. Another issue is sort of slime that could be produced by electrolysis, would pressure generated by water hose be enough to get rid of it from inside of tubes or maybe there are better ways?

I also need to protect internals of frame and the cheapest thing I came with would be just to pour bit of anti-rust paint inside and just shake frame to make it cover as much as possible. There's also boiled linseed oil, the thing is - it costs much more than raw one. And cheapest here is linseed varnish, but I am unsure is it possible to use them for protection.

Finally, type of paint. As I said, I could cheaply get some leftover lead paint but I am getting little paranoid reading about possible health hazards. Should I be even considering it?

One more thing, is heat gun safe for steel bike frame? I was thinking about quick-drying frame internals with it.

Where are you that you have leftover lead paint?

Use spray enamel or even rustoleum with a brush!

The car battery charger works because of the amperage, not the voltage. The phone charger won't work.

Fluid film aerosol will be enough to halt corrosion on the inside, once dry. The linseed oil would work too, and should be cheap. Boiled linseed oil is a drying oil and it's used to finish furniture. It will harden, don't use it. Linseed varnish is probably the same, and meant to harden, don't use it.

Is cuyd an artful troll? lead paint? 9V cell charger? This must be leftover from the '60s for the paint or the '90s for the charger.

Call it if they all about which chain lube is best.
:lol:

https://cimg8.ibsrv.net/gimg/bikefor...37737da03f.jpg


,,,this stuff works on the inside as a preservative, once you have a handle on the rust. Again at Home Depot about 6 bucks. Originally recommended to me by a local frame builder as what he uses. A heat gun works fine on bike frames, but don't use it after the interior oil treatment or it will just smoke off.

Does not make a good chain lube.

The lead paint, I got plenty of sources - some industrial/military leftovers are still possible to buy, I can get some second-hand from paint shop owners(not sure how they get it) or import it from most Asian countries. There's even red lead oxide powder for DIY paint, has to be mixed with linseed oil/putty and possibly turpentine or chalk, depends on needs as there are various recipes.

As for cell phone battery charger, here's some guy doing it on youtube - I've asked because I got plenty of those useless 90's chargers and I'm about to trash them. I got car battery chargers too, so no problem here.

[I can't post youtube links yet, so] /watch?v=WfZlFFrgxQw

You might want to price out the cost of all the materials that everybody has mentioned. Unless the bike that you are working on has sentimental value it's usually more cost effective to look for a donor frame that's in better condition.

That's sadly true. The frame was pretty good in it's prime but current value is close to nothing. The thing is, it's very hard to find anybody selling such frame. I really liked the geometry, as it was blazing fast and comfortable same time, something I can't archive with other bikes. If I would be going the cheapest way, instead of lead paint and electrolysis I would just go for cup brush de-rusting and leadless red oxide primer with cover paint on top. And I would just drip red oxide primer inside tubes, fill rest with some wax and call it a day. Perhaps I should do it this way, what do you think?

Yes, a heavy, toxic bike for you. :rolleyes:

Red lead oxide belongs on a wooden boat, and a wooden boat only. Do you have evidence of extensive rust inside the frame? Store it out of the elements and dry well, and you only really need to handle the exterior.

...this will work well enough for what you seem to have in mind. There are certain common points of failure due to rust on some of the better frames built of thinner drawn, high end steel tubing. So if it's already apart, check the stays where they join the BB shell for anything that looks like it might be rusting through. And I've seen some top tube rust in the thinner sections of the top tube that looked kind of troubling on bikes with internal cable routing. But a lot of steel frames will outlast you even if they look awful with regard to rust.

Not certain why you think this one has geometry that is both blazing fast and comfortable at the same time, but is unavailable in the used bike stream. There's almost every geometry and construction imaginable in the used bike stream.

Oxalic acid is highly toxic. I would not recommend it. A better solution would be phosphoric acid, which actually does a better job making rust inert. Boeshield makes a product called "Rust Free" which works quite well, and there are others on the market that are less expensive.

Do not use lead paint. Find one that has a zinc compound like zinc phosphate. These work very well. Locktite Extend Rust Inhibitor(?) is basically phosphoric acid in an acrylic polymer coating. It's thicker, has to be brushed on, but makes a good primer.

Worked a lifetime in coatings. Simply do not believe you can find a retail paint store owner anywhere who will sell you lead paint. Those guys live under a microscope and know the law. Light-fingered military and warehouse managers certainly exist, buy from them and you are breaking the law just as much as they are.

I know ways to get small quantities of lead paint. Some of them even legal. If I told you how to do it that would be illegal.

If there is any truth at all in the stories being told the party telling them certainly has no idea how to use the product safely. Just stop thinking about lead.

https://www.amazon.com/Gallon-Grade-Phosphoric-Remover-Clean/dp/B06XZSW3QX/ref=sr_1_6?keywords=phosphoric+acid&qid=1569936741&sr=8-6

This stuff is 85% pure, food grade to boot. I've used it on rust. Dissolves it and turns it black. Beer brewers use it to adjust the PH of the water they brew with, all you need is a few drops.

Thank you for that link! The local hardware store no longer carries it, and my supply was getting low.

What about de-rusting with citric acid? I found it to be pretty cheap and afaik it's less toxic than other acids. I could make a makeshift container for frame and just fill it with water and acid then wait for few days. Seems I could just clean it with pressure water and no other chemicals, but would it be effective in de-rusting?

Also, people suggesting various methods but I found that most of them leave sort of slime left that has to be brushed off. Thing is, I won't be able to brush it off internal parts of frame and the only thing I got is pressure water. But pressure water might cause flash rust to appear...

Citric acid is unlikely to produce the results you want. It can even promote corrosion, especially in concentrated forms. You don't just want to remove the rust, you want to rust-proof the metal. Phosphoric acid is also a relatively weak acid, but does not promote corrosion of ferrous metals. It combines with iron oxides to form an insoluble iron phosphate. The process is called phosphatization, and is used to rust-proof ferrous tools, especially military equipment and firearms. Commercial phosphatizing solutions are available and faster than phosphoric acid alone.

Any chemical agent that you use is likely to be hazardous to one degree or other. Read and follow safe handling procedures