How can I remove rust from a bicycle?

Question

I came across an abandoned old classic bicycle. I was thinking of restoring it but the biggest obstacle is all the rust! It's super bad. Does anyone have any recommendations on what to do?

Answer 1

Presuming you intend to ride this bike - start by checking the bike over closely. You do not want to get part-way through a restore and find some part is broken/missing and is hard to find. Old bikes can be difficult to get parts for.

Also, make sure the bike will fit you when its re-assembled ! Would be gutting to spend time and money on a bike that turns out to be too small. Many old bikes tend toward the smaller sizes.

1. Start by photographing any decals or stickers. They may not survive a clean.
2. Wash the bike with soapy water and an old dish brush and lots of gentle sprinker washing. Allow to drain/dry in the sun.
3. INSPECT. Top to bottom, underside, close look at every weld/braze. Push/pull firmly on chainstays and dropouts etc. You're trying to find reasons to not do the restore, so you're going into this with eyes open.
4. Dissassemble - remove all component assemblies off the bike. Take photos of anything you're not sure of. Store bolts with nuts back in the hole they came from.
5. Power wash the whole frame and wheels. Normally this is bad, but you're probably doing a balls-up rebuild of all the bearings anyway.
6. INSPECT AGAIN

Now you've got a bunch of photos, a clean but rusty frame, and bags of part components.

Figure out what you have both from the disassembly, and from your own parts bins. Identify what you'll need and start sourcing them. Scour ebay/gumtree/trademe and if the Right part comes up, buy it.

Also decide what kind of rebuild you want - a concourse rebuild with shiny paint and chrome? Or just enough to ride it?

Also decide your budget - these have a habit of being broken.

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Once you have a general idea of results, clean the frame. Your options are:

1. Sandblast it (maybe glass bead, walnut, or other abrasive) This will remove all the paint and stickers, leaving the steel bare. You would prep the frame by masking off every threaded area. A commercial blaster will spray the whole thing with grey weld-through primer to stop it flash rusting, but this is not a long-term coating. This is not something a home user would do, it has a cost.

2. Sand it yourself - cheaper but time consuming. You could use sandpaper, a brass-wire wheel, a rolock sander, etc. This make a heap of rusty dust so PPE mask/eyes/ears is important.

3. Convert rust - there are paint/spray on converter chemicals that will change the red rust into black oxide. They are often high in phosphates and the black iron-phosphate is not going to continue rusting. However this has a surface finish that is not flat and will make the bike look awfully lumpy. Can be combined with clear-coat paint on the frame too.

Personally I'd go with #1 if I had the cash, and a combination of #2 followed by #3 to catch whatever I don't sand off.

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Mods - now's the time to add bottle cage mounts, mudguard mounts, brake mounts, or any other brazeon fittings. Do before you paint.

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Protection - after cleaning the frame you need to protect it, else the rust will return.

1. Powder coat - a plastic layer that is firmly baked onto the outside of the frame. Costs money and needs a pro to do it with ovens etc. Very hard wearing finish.

2. Galvanising - this is uncommon in bikes cos its kinda ugly, but car/trailer/truck chassis are often hot-dipped in a bath of molten zinc. You can do this first then apply other options

3. Spray paint - this could be an air sprayer with a 2 part paint, through to rattle cans from the local bigbox store. The tricks are to use compatible primers and base layers, allow paint to dry, thin coats, light scuffs between coats, and cleaning all the dust off. You also want multiple clearcoats.

4. Bare - not recommended, this allows the rust to return. You might choose to leave it Ugly, and simply have a bunch of clear layers to keep the rust off.

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Components - while all that is happeneing, focus down on a component set and clean it. Sometimes a wash is all you need, sometimes it needs a complete strip-down and inspect. Anything with bearings needs repacking and check all the bearing surfaces. Replace all the bearing balls too.

I've found that chasing threads is helpful too, as long as you have the exact same threads.

Rechroming parts is hard for the home user, so again send out anything that has to be shiny. You can use electrolysis to replate parts with Nickel etc.

Having all the parts clean means the rebuild goes easier.

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Reassembly - put the bike together.

Start by putting fishoil or "automotive frame protector spray" in every tube of your bike. These products often come with a long applicator straw that you can feed into chainstays and seat stays because the BB and seatpost are out. This will prevent new rust from forming while smelling awful.

Expect to replace all the rubber. That's tyres and tubes, rim tape, brake pads, bar grips or bar tape, and possibly the saddle and pedals if they're too far gone.

There's a lot more detail, but a full bike rebuild will take weeks at minimum, and probably months. I wouldn't be surprised if it takes years either.

Have fun!

Answer 2

Yes. Use rust converter inside the frame. It's quite runny. Remove everything from frame, block the bottom bracket, head tube, and add copious amount of it thru seat tube, and shake.

Removing surface dust is easier. Use angle grinder with a brass brush. It will quickly remove rust without creating too much swirl marks. Then, sand with 800 or finer grit, wet. Apply thick primer. Then paint.

Chrome parts can be cleaned by polishing paste and buffing wheel. It's cheap, fast and effective.