Pioneer Silver Era Knobs- SX-780- Refinishing Tips?

Discussion in 'Pioneer Audio' started by Arthur Smith, Jul 10, 2018.

  1. Arthur Smith

    Arthur Smith Well-Known Member

    Messages:
    822
    Hi, I have noticed on my 780 knobs that the silver paint, or plating, or whatever they used 40 years ago, has started to fade off, revealing a whitish plastic underneath. Is there an "easy" way to refinish the knobs that members here have used with success? Thanks, Arthur
     

     

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  2. Watthour

    Watthour Electron Rancher - JS3600

    The switch caps and potentiometer knobs are aluminum. These were hard anodized to prevent oxidation and dulling. If the anodized layer is worn through, the aluminum will turn a dull white/gray color. These can be either re-machined or polished, then anodized again or covered with a clear coating while they are still bright.
     
  3. Arthur Smith

    Arthur Smith Well-Known Member

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    822
    Polished with what, exactly?
     
  4. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    Your not going to be able to polish them. They are anodized, that bakes deep into the aluminum. It's pretty hard to strip ALL the anodizing off but can be done. A professional service can strip and reanalyze them but would be cheaper to just buy better ones.

    If I tell you what strips the anodizing, you'll probably do it but then the knobs will just oxidize looking worse than what you have now.

    Someone probably already soaked them in a cleaner that harmed the coating turning them whitish.
     
  5. Arthur Smith

    Arthur Smith Well-Known Member

    Messages:
    822
    What if I just find a chrome-like paint, and shoot them with that? I'm not super picky, but I just want them to look better.
     
  6. savatage1973

    savatage1973 Addicted Member

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    Most paint will not stick to aluminum without appropriate preparation and priming--especially in the existing condition--so an $8 can of spray paint is not likely going to "fix" anything.
     

     

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  7. Arthur Smith

    Arthur Smith Well-Known Member

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    I guess I am going to leave them as is. Thought someone might have some type of suggestions.
     
  8. savatage1973

    savatage1973 Addicted Member

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    Location:
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    I have no idea if this will even remotely work, but I'll throw it out there... I would not try this with one of your knobs without testing it on something that you don't mind throwing away, but if you know someone that polishes brass for reloading ammunition, try dropping it in one of the drum type machines (no chemicals, just the dry abrasive) and let it run for a little while. I would guess if it turns out nice, you would have to seal it with some sort of clear-coat to protect it when done. I guess the ones for polishing stones are about the same, but I don't know the grit levels of abrasives used in them.

    EDIT--brain fart when I posted--the real name of the machine is a "tumbler"--used for polishing brass, jewelry and stones.
     
    Last edited: Jul 10, 2018
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  9. Watthour

    Watthour Electron Rancher - JS3600

    Polish the aluminum with a rouge wheel, then coat or anodize it immediately, before oxidation can occur and dull them again. Metal finishers do it all the time.

    You can also polish them then apply acrylic or urethane clear coat, but it is not as durable as the anodized surface.

    http://lmgtfy.com/?q=anodizing+aluminum
     
  10. EastPoint

    EastPoint Factory Code No. 4200 Subscriber

    Messages:
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    Location:
    Milwaukee, WI
    I’ve seen Technics SA-300 (200, 400, etc) lever knobs do that, but they just seem to be painted. I don’t think I have ever seen SX-780 knobs with that issue.
     
  11. john stumpf

    john stumpf AK Subscriber Subscriber

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    Location:
    philippines
    company called caswell sells a home anodize kit,tried it once in my motorcycle days. if you like to fiddle around. i wouldnt send it out as commercial polishing/polisher's will be expensive and make the ebay prices seem quite reasonable. ebay is what i would do.
     

     

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  12. Arthur Smith

    Arthur Smith Well-Known Member

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    822
    I am not looking to go crazy with this. Thought there might be some kind of simple solution.
     
  13. savatage1973

    savatage1973 Addicted Member

    Messages:
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    Location:
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    Some Simichrome and a toothbrush. Grab a couple beverages and allocate a couple hours of your time. Any MC shop carries Simichrome.
     
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