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Removing rust from an old steel frame

annoyingtwitannoyingtwit Posts: 127
edited March 2016 in Workshop
I have an old steel (531) framed bike which has some rust spots.

What should I do about them? From a quick google it seems that the correct strategy is to clean off the rust (e.g. aluminium foil - does this really work?), sand down the area, then spray with automotive paint. I can knock the frame to check for a 'dead' sound to work out if the rust is structural. If it is, then I need a new frame(set).

Any advice on this, or is the above a 'plan'? If I'm not sanding down the entire frame, just spots, then there must be edges around the sanded area. What happens when I spray paint around them? I think that stripping the entire frame is beyond the time that I can afford to spend on this.

Posts

  • sungodsungod Posts: 16,093
    various methods, depends on the extent

    http://www.sheldonbrown.com/paint-prep.html
    my bike - faster than god's and twice as shiny
  • Thanks. I'm off to B&Q for some gardening stuff. I don't care what the result looks like, so I will paint on some enamel with a brush. I am not too worried by drying time, and marine enamel sounds expensive and fiddly. Removing the rust is more tricky? Phosphoric acid? I think that fine sandpaper will be better. I didn't know about sealing the inside of frames.
  • FishFishFishFish Posts: 2,152
    I don't care what the result looks like,

    Good man!
    ...take your pickelf on your holibobs.... :D

    jeez :roll:
  • FishFish wrote:
    I don't care what the result looks like,

    Good man!

    It's an old bike that a few weeks ago I thought would never turn a wheel in anger again. I decided to use it to practice maintenance stuff on. It now has a rebuilt rear wheel with new DT Swiss spokes, new chain/rear derailleur/freewheel, and now I'm working on rust spots. I'm alternating my technical posts between here and another forum. It's getting close to being in good condition for its age, and perfectly rideable. It's also now got more gears than it used to have 10-->12. I have a sort of perverse pride that it looks like a heap of junk, but mechanically it's getting better and better.
  • arlowoodarlowood Posts: 2,561
    How much are you prepared to spend on it?

    Reason I ask is that a couple of years back I looked into the options for fettling up a steel framed bike to give it a new look and colour scheme.

    At the time I looked into the option of having it powder coated and found a fairly local powder coating company who offered to do the lot for £60. By "the lot" I mean sand blast the old frame back to bare metal then apply powder coat in a standard colour. All sensitive threaded areas etc would be masked appropriately

    They had a limited range of colours and the deal was that when they had a job to do with a run of, say, red they would slot in the frame in that batch. Hence the relatively cheap price but it meant waiting until they had a run of the colour I wanted

    The project nose-dived when I realised that the frame had a carbon fork which would not survive the powder coating process.

    If you are prepared to spend a little bit you might be able to find a similar company in your area.
  • £60 is a bargain. I looked, and a local company will do it for about £140, though that's regular price.

    I don't think it's worth spending that much on this bicycle. It only cost me £65 in the first place. I'm using it to practice technical stuff myself. If I was going to have it painted I'd strip the paint and spray paint it. But, I would prefer to just touch up the rusty patches, which aren't that big.

    I'm encouraged by Sheldon Brown's experiences, where a bit of DIY on a frame resulted in a frame that lasted another 30 years. I'm not sure that I'll last another 30 years (though I hope so :) ).
  • arlowoodarlowood Posts: 2,561
    £60 is a bargain. I looked, and a local company will do it for about £140, though that's regular price.


    I think the £60 figure was so low because they do largish volumes of other components and as long as you were happy to take a colour that was being applied in a large volume batch then the addition of the frame into that colour run added a low incremental cost.

    May also be partly a geographical thing - I live in the East Midlands and the company is based locally so maybe the unit costs are a bit lower than elsewhere.
  • arlowood wrote:
    £60 is a bargain. I looked, and a local company will do it for about £140, though that's regular price.

    I think the £60 figure was so low because they do largish volumes of other components and as long as you were happy to take a colour that was being applied in a large volume batch then the addition of the frame into that colour run added a low incremental cost.

    May also be partly a geographical thing - I live in the East Midlands and the company is based locally so maybe the unit costs are a bit lower than elsewhere.

    Thanks very much for the information. BTW: I also live in the East Midlands, in Leicester.

    I'm just starting another project today, and I note that the carrier on this new one has some rust. (Alloy frame, so no rust there.) I'm going to practice removing rust and repainting the carrier first before moving onto the frame.
  • fudgeyfudgey Posts: 854
    In birmingham is city powdercoaters, they shotblast and powdercoat. Pretty good job they do, i had a set of car wheels done for £20 a rim. Think a bike frame is £35. Lots of colour choice too.

    As for removing rust, sandpaper will do it, the finer the grade the less scratches.

    Or use one of these:

    https://m.youtube.com/watch?v=CLaBFkeHG0A
    My winter bike is exactly the same as my summer bike,,, but dirty...
  • keezxkeezx Posts: 1,322
    I have an old steel (531) framed bike which has some rust spots.

    What should I do about them?

    Anle grinder with steel brush > blank> sand around these spots> primer these spots> sand lightly> spray 2x or 3x local with rattle can> JOB DONE.
  • Keezx wrote:
    I have an old steel (531) framed bike which has some rust spots.

    What should I do about them?

    Anle grinder with steel brush > blank> sand around these spots> primer these spots> sand lightly> spray 2x or 3x local with rattle can> JOB DONE.

    Thanks for the advice.

    I haven't got an angle grinder nor steel brush. I'm going to try sanding directly and see if it works. I've got a rattle can but also some brush on enamel paint. This is the first time I've done this, so wish to experiment.
  • SMESME Posts: 348
    I've heard of a few homemade concoctions that seem to mostly use white vinegar or lemon juice, laced with baking soda, brushed on and left for a while before rinsing off. Never had to use such myself though, so can't vouch for them.
  • I chose a bit on the right seat stay which had some patches of rust busting out of the paint.

    I tried using white wine vinegar on it, but I didn't manage to get the rust off. What helped was using some fine sandpaper, and a sanding block. The rust turned out to only be surface (though, not trivial 'surface') so I soon got down to bare metal. I tried some silver pound shop automotive spray paint, but the result looked awful. Painting on some silver enamel gave a better result. It won't fool anyone, even from a distance it looks exactly as if it has been repainted by hand. But I'm happy that I can remove rust and repaint so that the rusting of the frame will be slowed.

    One good, in a way, thing is that my 'Reynolds 531' stickers say nothing about double butted tubing. So, they're probably straight tubes, and therefore there was more tube thickness to rust through. I think that if I choose various bits to clean and repaint, then over time I'll end up with a dreadful looking frame, but one that has a much better protective coating.
  • SportivemanSportiveman Posts: 157
    I would use a rust remedy eg a gel you brush on leave ten minutes and wash off it takes all rust out and Gos to bare metal works brilliant on cars can't see it being much different a pot is about £5 for a holts rust gel. Just make sure to use a touch up to stop it re rusting
  • Baking soda is one of the most widely used and efficient chemicals for rust removal on bicycles. To make a paste out of baking soda, combine it with water in a 50/50 combination. The rust must be entirely coated with this paste, which will be put to the surface. Allow the solution to sit on the surface for around 15 minutes.

    After 15 minutes, use a scrubbing pad or a toothbrush to scrub the baking soda solution. You will see the rust breaking and falling off the surface. If not, apply more baking soda solution until the rust will be removed.
  • davidofdavidof Posts: 3,023

    I tried some silver pound shop automotive spray paint, but the result looked awful.

    I did this with rattle cans:

    https://youtu.be/fh4YC-aTzfU

    rust is hard to cure permanently.

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