• You can put a stainless steel strip on that chain stay.
    For the rest of the frame: there may be some goodies in the market that you can spray / wipe on to your frame to protect it against rust, but I don't know that so well.
    You could do some research.
    Or consider an extra layer of clear coat, but still that will not stop the corrosion completely. Maybe you have to speak to a real painter and ask for his opinion (as long as the frame doesn't get a full repaint).

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