surface rust chainstay bridge area

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  • hi, i have a dawes audax from the mid 1990s which has got a lot of surface rust on and around the chainstay bridge area. It seems to have spread under the plasticky coats the factory put on . I've got most of the rust off with a little rotary wire brush attachment on a drill, thinking of wire wool to get the rest off (in awkward spots) . when I did a similar job before i used zinc primer after getting it down to shiny metal, with an automotive top coat on it lasted years.

    does that sound like a plan ? maybe use kurust for the bits i cant quite get shiny ?

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  • of course long experience, tells me these problems are like icebergs - you dont realise the extent of the problem until you really get into them !

  • If the original finish is anything like powder coat then clean off what you think you need to plus a good bit extra, water can get right under powder coat and sit there doing its thing without you realising until it’s too late.

    Zinc primer definitely a good idea, I use it when I’m painting frames I’ve built and send to do a good job of keeping the rust at bay.

  • Yeah I've given it all the full works ... Kurust .... Zinc primer .... Smoothrite.

    At least it should keep it at bay for a few years when full powder coating will be necessary I think. Amazed how far it had spread under the powder coat.

  • Amazed how far it had spread under the powder coat.

    Well, this seems to be typical of powder coating (as mentioned elsewhere). I think the problem may be that there is a belief that powder is a one coat finish. Probably, if the work were primed properly this wouldn't happen. Yellow etch primer will not inhibit the electrostatic effect which the powder needs to make it stick to the frame, but it would go a long way to preventing rust.

    The difficulty is that you have no control over what actually happens in the paintshop.

    I doubt whether anyone would try to get away with one coat of stove enamel - the shot blasting would show through, but it's common practice to do this with powder.

    Moral: Stick to wet paint (stove enamel) for bike frames.

  • Sorry about multiple posts. Anyway this is the finished article. These areas always take a battering I think even with mudguards but this should suffice for a few years

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surface rust chainstay bridge area

Posted by Avatar for iggypop37 @iggypop37