How should I treat surface rust where there is silkscreen?

Discussion in 'Hobby Engineering' started by /invariance\, Apr 18, 2019.

  1. /invariance\

    /invariance\ Member

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    I have a B&O amp (Beomaster 1900) that I am going to partially restore. I say partially restore because I am not going the whole hog with applying new timber veneer/full recap/transistor upgrades/etc.

    My problem is the metal base and rear panel is suffering from surface rust and I am looking for ideas on the best way to at least neutralise the rust without affecting the silkscreen?

    How well would diluted white vinegar work whilst not affecting the silkscreen?
    Post treatment? Clear lacquer or car wax?

    Thoughts/suggestions/ideas welcome. :)

    IMG_1468.JPG
     
  2. aXis

    aXis Member

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    Phosphoric acid will covert rust to a stable form. Bunnings has it as "Ranex" rust converter.

    No idea about it's impact on the silkscreen.
     
  3. Jazper

    Jazper Member

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    You could try white vinegar, try a drop of it on a small area first to see. It coupled with a little elbow grease/cloth tends to work well
     
  4. Matthew kane

    Matthew kane Member

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    Sorry none of the solutions thus mentioned will work without removing the silkscreen on the plate, doing more damage than the original state. I do restorations and rebuilds with vintage audio (both valves and solid state) on the side and the only way you're going to restore that plate is by getting it completely sanded down, rust converted then blasted with walnuts with a finish either powder-coating or spray painting it black and have a new silkscreen applied. This is only worth it if the return is worth the effort and costs involved. Easiest way is to leave it and seal it or buying a replacement piece off ebay (spare part from donor).
     
    firey4059 likes this.
  5. OP
    OP
    /invariance\

    /invariance\ Member

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    Thanks everyone.
    I suspected this would be the case.
    I’m kind of tempted to wax just the silkscreened area and sand/repaint the rest as I don’t really have the time to make this a full on project.

    I suppose to be honest, I’m a little daunted with the silkscreening aspect and eager to have it connected.

    I should think on it more and convince myself to do it properly :)
     
  6. Matthew kane

    Matthew kane Member

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    Don’t apply any car wax product onto the rusted plate because they may react with the degraded parts of the plate and you will have this whiting splotches over time.

    Clean the plate and seal it with 2X rustoleum clear spray paint.
     
  7. OP
    OP
    /invariance\

    /invariance\ Member

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    Might just do that for now as the amp is from my father in law and he would like to hear it going again as he is getting quite frail.
    I hope to get back to it and do a proper job.
     

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