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  1. #1
    Join Date
    Dec 2007
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    Default How to clean rusty bolts

    I usually clean up rusty bolts on the bench top grinder with a wire wheel.

    I’m wonder if there is a cheap and non toxic chemical option which could be used on bolts by the handful perhaps left for an hour or overnight?

    Something that doesn’t require a secondary process to make them presentable again after.
    I tried one of the commercial acid based solutions which worked converting the rust. It works on the surface only so good for light rust. The problem it leaves a dull grey finish with white residue that isn’t presentable.
    …..Live a Quiet Life & Work with your Hands

  2. #2
    Join Date
    Mar 2017
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    Default

    Have a look at Evaporust. Not so cheap, but works well, environmentally friendly, and neither acidic or alkaline on the steel (or your hands). Cheers, Tony

    Sent from my SM-G955F using Tapatalk

  3. #3
    Join Date
    Aug 2011
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    Melbourne
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    Default

    You have no doubt already heard of this option, but I have used molasses with great success. It requires a bit more time than just overnight but after 2 weeks in a 10 parts water 1 part molasses solution the parts come out beautiful.

    I have also used electrolysis too which is OK. A bit quicker too although not as forgiving as the molasses solution.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  4. #4
    Join Date
    Jul 2012
    Location
    Griffith NSW
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    435

    Default

    Using a wire wheel on a bolt / screw is a bad idea, it creates lots of little nicks and slices on the surface of the thread. At the bottom of the thread valleys, a nick in the surface can be a stress raiser and allow the beginnings of a crack. If its just some nice bolts for your workbench, meh, send it. But if its mission critical, DO NOT wire wheel. Buy new bolts.

  5. #5
    BobL is offline Member: Blue and white apron brigade
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    Default

    I have not tried any of these but the cheapest solutions involve the use of a weak organic acids like oxalic, citric and vinegar.
    I'm told citric acid acid acts like a fast acting molasses and will not dissolve raw steel.
    This is another experiment I will do when I get around to it.

    Once you get them done remember you will have to act quickly to put a protective coat over the raw steel or it will rapidly rust again

  6. #6
    Join Date
    Jul 2008
    Location
    near Warragul, Victoria
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    3,718

    Default Citric

    Quote Originally Posted by BobL View Post
    I have not tried any of these but the cheapest solutions involve the use of a weak organic acids like oxalic, citric and vinegar.
    I'm told citric acid acid acts like a fast acting molasses and will not dissolve raw steel.
    This is another experiment I will do when I get around to it.

    Once you get them done remember you will have to act quickly to put a protective coat over the raw steel or it will rapidly rust again
    Yes citric acid is great for these little clean up jobs. Having restored a few pressure lanterns , the citric is a wonderful cleaner and it isn't that nasty either.

  7. #7
    Join Date
    Aug 2006
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    Melbourne
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    Default

    Is the molasses reusable over and over again? I've always wanted to give it a go, it seems that it is available at coles.

  8. #8
    Join Date
    Nov 2017
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    Default

    I think the molasses starts to degrade over time, but mine still works from the original brew after 12 months.

    Not sure if Coles prices, but our local rural supplies place was around $25 for 20kg last time I bought it.

    Steve

  9. #9
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    May 2011
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    Just wondering, will molsasses plus any of the previous mentioned solutions remove the millscale from new steel?
    Kryn
    To grow old is mandatory, growing up is optional.

  10. #10
    BobL is offline Member: Blue and white apron brigade
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    Default

    Quote Originally Posted by KBs PensNmore View Post
    Just wondering, will molsasses plus any of the previous mentioned solutions remove the millscale from new steel?
    Kryn
    The weaker organic acids take around 24-48 hours to remove mill scale.
    If you want to do it quickly get some concentrated Hydrochloric acid (HCl) as this will do it in around 30 minutes depending on how thick the scale is.

    Precautions for using HCl
    Carefully read the MSDS
    Wear gloves, eye protection and clothing protection as HCl will dissolve clothing. It may at first not appear to do anything to clothing but the next time you wash you clothes any HCl splashes will turn into holes.
    If you get any on your skin immediately continuously flush the area with copious water like you would for a burn. You may not feel anything at first but later it can feel like a cigarette burn.
    The pickling should be performed outside as the fumes can literally take your breath away.
    Avoid doing the process inside a shed as the fumes will end up rusting every bit of exposed metal.
    The process generates hydrogen so use a container that once filled with steel and HCl leaves little volume behind in the container so the H can easily float away.
    Before you remove the steel from the pickling bath have a bath of neutraliser (baking soda) ready to neutralise the acid or it will start rusting immediately.
    Leave the pickled steel in the neutralising bath for a few minutes after the steel stops bubbling.
    Then rinse off the neutraliser with water and use an oil bath or spray, or paint primer ready to add protection or it will still rust.

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