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Rust never sleeps!

Discussion in 'Amps and Cabs [BG]' started by ficelles, Dec 23, 2017.

  1. ficelles


    Feb 28, 2010
    Devon, England
    Slightly OT as this about a guitar amp not a bass amp... but anyway while replacing a volume pot and doing a quick service I noticed the transformer on my Mesa Boogie Nomad 45 has signs of corrosion. I haven't owned the amp that long so it must have been already like it when I bought it, strangely though the rest of the combo including the speaker and cabinet is in mint condition, not a mark or sign of other rust anywhere. Any ideas? More importantly, should I worry about replacing the transformer?

  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Not a problem.
    Kro and ficelles like this.
  3. BadExample


    Jan 21, 2016
    You should see my variac! Spooky.
    Kro likes this.
  4. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Rust is a good insulator and doesn’t harm the transformer unless it is really bad and eats away too deep between the plates. Trying to remove it can harm the transformer if you remove the protective coating that is present between the plates.

    Your transformer looks fine.

    At the same time, if the rust bothers you...Never use a wire brush to grind it off from the plates in the center. I gently remove any loose rust, then apply a transformer insulating lacquer such as Corona Dope: 4226 - Super Corona Dope - Insulating Coatings | MG Chemicals.

    A transformer manufacturer once recommented dabbing on a thin coat of an oil based urethane or a rust paint such as Rust-Oleum. Both seal and protect, the paint converts the rust.

    The end bells can be cleaned of loose rust and the same type of rust stop paint dabbed on to make it look nicer.
    deathness likes this.
  5. farace


    Jul 9, 2016
    Connecticut USA
    [QUOTE="beans-on-toast, post: 20753881, member: 123838

    The end bells can be cleaned of loose rust and the same type of rust stop paint dabbed on to make it look nicer.[/QUOTE]

    There is a product called Evapo-rust that shockingly does exactly what it claims to do. I use it mostly on car parts myself, but I bet it would take the rust off the bell covers. It won't bother the paint, and it's even safe on skin as it's not corrosive. I would take the bell covers off, of course, before soaking them. :D Then a good paint as mentioned above.

    Then there's always POR-15. POR stands for "paint over rust"; it chemically combines with the rust. Won't be as pretty as removing it. It's mostly used on car chassis and suspension parts.
  6. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    I use Evapo-Rust as well. Good product.

    For something like the bell ends, I use a product called Restore Rust Remover Gel. Being thick, it stays where you apply it. You don’t have to soak the part in it like some other products. The stuff is expensive but a little goes a long way.

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