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Thread: Derusting with Molasses: Version 2

  1. #1
    Registered User Lurch's Avatar
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    Derusting with Molasses: Version 2

    After TK discussed De-rusting a Holden V8 block with Molasses in this thread:
    http://www.performanceforums.com/for...-with-molasses
    I thought everyone might be interested in how I used Molasses to de-rust a bonnet.

    Backstory:
    I'm helping my brother restore his Mk1 Austin Healey Sprite.



    When he bought the Sprite as a disassembled project, it came with a repoduction fiberglass bonnet. Originally these cars came with a one piece steel bonnet and Brotato
    wanted to restore the Sprite with an original steel item - problem being, these are now rare and good bonnets command silly prices.

    He found a bonnet on Gumtree in Perth that was a bit sad in condition, but it was complete and fairly unmolested.
    It had however been media blasted, given a light coat of Red Oxide then left to rust some 15+ years ago.
    He bought it for a few hundred dollars and I had it shipped over.





    Now I didn't want to have it Garnet blasted again to remove the rust and risk warping the already thin steel.
    Soda blasting was out as it won't effectively remove rust this ingrained, it could also warp the panels and it's an expensive process to have done.
    I considered sanding & wire buffing the rust then applying phosphoric acid, but this is laborious and probably won't remove every last spec of rust.

    The Molasses bath seemed like the best solution as I had success with this technique before on engine tinware (rocker covers, timing covers etc).
    So we unpicked the guards off the centre section of the bonnet - as the T-beading had rusted away and would have to be replaced - as well as the radiator intake ducting etc.
    I then went on eBay and bought a cheap 800ltr inflatable pool for about $140, bought 40ltrs of stock feed Molasses, filled the pool up with water and immersed the bonnet in it:



    We then mixed in the Molasses covering the part of the bonnet we wanted to de-rust (we are replacing the lower valance as it's beyond repair) :

    Last edited by Lurch; 13-06-18 at 07:27 PM.

  2. #2
    Registered User Lurch's Avatar
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    We then covered it over with a tarp and left it to do it's thing.
    A few weeks later we exhumed it for the mix to find that the rust was totally eaten away:



    A scrub with a scotch brite pad and wire brush while hosing the Molasses goo and remaining scale off with water left us with a rust free bonnet:





    Showing the line where the Molasses sat at:



    At this point the bonnet had flash rusted from being exposed to water and atmosphere, so I sat it in front of my Jetfire diesel heater to dry off.



    Once dry I we gave it a coating of Phosphoric Acid to remove the flash rust and left it to dry:



    The remaining red marks are painted lead & body filler which I have now removed.
    I just haven't had a chance to take a photo of the bonnet as it sits now, but IMHO this is the cheapest (under $200) and easiest way to de-rust this panel.
    Now we just have to do the guards & radiator ducting. I'll add some more photos to this thread when we've got all the parts/panels done.
    Last edited by Lurch; 13-06-18 at 07:29 PM.

  3. #3
    Registered User dnegative's Avatar
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    Photos not working
    Quote Originally Posted by cracka View Post
    Fuck I'm retarded

  4. #4
    Registered User Lurch's Avatar
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    Edited - hopefully that works.

    Edit 2: Photo hosting is not playing ball - I'll fix it tonight.
    Last edited by Lurch; 11-06-18 at 07:38 AM.

  5. #5
    Defective Faux Forg's Avatar
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    Excellent!
    Quote Originally Posted by Marlin
    Chickens will slip under water in the cover of darkness like a seal team and FUCK YOU UP.

  6. #6
    Registered User GreatWallGT500's Avatar
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    I cant wank if theres no pics

  7. #7
    no mods, leave it stock Jack Nicholson's Avatar
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    Wow great result!

    That last pic with half the bonnet done says it all!
    Jaguar XJR, Freelander 2 HSE, Jaguar XKR

    Quote Originally Posted by Marv View Post
    Look, just because you drive a couple of imported luxo Pommy cars doesn't mean you need to act like an Imperialistic Lapdog and be the last bastion of defence for Straya The Beaut's mid-20th-Century ideals
    Quote Originally Posted by nutttr View Post
    People must assume you are some sort of drug dealer with all these nice cars turning up to a fibro home

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    Registered User
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    Only two pictures show for me

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    Registered User I'm DJ!'s Avatar
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    Also no pics loading, but keen. That looks like a great result
    Quote Originally Posted by thebluerx7 View Post
    The fact they want to ban cash makes me want to go out and use it full time again now .


  10. #10
    no mods, leave it stock Jack Nicholson's Avatar
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    I can see all the pics on tapatalk
    Jaguar XJR, Freelander 2 HSE, Jaguar XKR

    Quote Originally Posted by Marv View Post
    Look, just because you drive a couple of imported luxo Pommy cars doesn't mean you need to act like an Imperialistic Lapdog and be the last bastion of defence for Straya The Beaut's mid-20th-Century ideals
    Quote Originally Posted by nutttr View Post
    People must assume you are some sort of drug dealer with all these nice cars turning up to a fibro home

  11. #11
    Registered User Lurch's Avatar
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    I've re-hosted the images - so they should all be visible now.

  12. #12
    Resident Oaf Jim's Avatar
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    Yep works now. Awesome job!
    Turns out, far too much has been written about great men and not nearly enough about morons


    Quote Originally Posted by seedyrom
    my neighbours called the cops...... not because of the sound of me working in the garage was too loud, but because i taped a cardboard box to my back, covered my self in vaseline and pretended i was a snail on their lawn

  13. #13
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    Awesome to see how well the bonnet cleaned up - must be good quality metal as I've seen plenty of old American tin take months and months to get anywhere near that clean.

    For cleaning flash rust and light scale I use Oxytech Anti-Ox (spray-on liquid) and then once that has dried I spray on Easy-Phos (also from Oxytech) to stop it rusting. It'll stay in good raw condition for 6 months if left indoors and you don't rub your bare hands all over it. Sure its more expensive than Bunnings Phosphoric Acid but it is also really convenient.

  14. #14
    anyone? MRMOPARMAN's Avatar
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    Worked awesome!

    Anyone got an actual proper pool i csn borrow? I have valiants and an E21 that could do with a dip!
    Quote Originally Posted by Rdyno
    70ynu has to be the most retarded cunt here. "Help me please" me "you need to remove your head" him "fuck off cunt I'm to lazy fuck off out of my thread you told me to do something I don't want to do so you're a cunt fuck off can some one please tell me an easier way???"
    Quote Originally Posted by Tripper
    Its a tight battle between you and rogercordia for the most retarded member on here, thou i think you have it by 5 window licks

  15. #15
    PF's Bogan Luxury Dept TUFGMH's Avatar
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    Great work, impressive result

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