Viewing 27 posts - 1 through 27 (of 27 total)
  • Metallurgists – help with aluminium
  • Jolsa
    Full Member

    I’m having fun trying to restore a metal cart. I found Cillit Bang gave it a decent clean and Autosol metal polish cleaned it further yet simply emphasised the scratched/worn areas.

    Hence I’m still wondering how to get to a more even finish that reduces the scratches with just elbow grease as power:

    I’m assuming it’s anodised aluminium, with the scratches/wear marks revealing the shinier look beneath.

    Is it possible to even it all out to an acceptable state without having to use power tools? I’m thinking of having a go with a “Garryson Aluminium Oxide Very Fine Abrasive Block 240 Grit” next, but would I be wasting a fiver? 🙂

    I don’t think I could do much more Googling, so hoping a STW bod who knows their stuff could give me a few pointers?

    jemima
    Free Member

    If it’s anodised leave it to soak in a bath of caustic soda solution. Bit of fine grit wet and dry afterwards and it’ll come up a treat. But won’t be anodised obviously so might need occasional polishing to keep it shiny.

    NOTE: I am not a metalurgist

    ahwiles
    Free Member

    wire wool then T-cut?

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    rascal
    Free Member

    What a refreshing change.
    A genuine ‘ist’ as opposed to a wooderist, vanerist, runnerist etc etc 😉

    TPTcruiser
    Full Member

    Why polish?
    If it is anodised won’t polishing take away the coating and just accentuate the surface scratches. Unless you go down into the surface to the depth of the deepest scratch.

    muddy9mtb
    Full Member

    the scratches on your alu look far deeper than elbow grease is gonna remove – look at youtube for alloy wheel repair to get some idea on how best to go about it.. will probably involve a power tool of some sort.

    globalti
    Free Member

    I don’t think it was anodised, unless it was yellow and has faded badly in UV light. Looks to me like a brushed satin finish followed by lots of atmospheric dirt including tars, maybe from smokers? If you want a perfect finish, as above, polish in progressively finer grades of wet ‘n dry finishing up with abrasive paste polishes, through Solvol Autosol to car polish, which is the finest. Then protect it with a spray lacquer if it’s going to be in a damp environment.

    sandwicheater
    Full Member

    Cover it in stickers.

    cheekyboy
    Free Member

    What kind of metal cart ?

    globalti
    Free Member

    Looks like an airline meal cart to me. Is the OP starting a budget airline?

    Jolsa
    Full Member

    Ha, I’m no Stelios, but yes it’s an airline cart. Thanks for the responses so far, brushed satin finish sounds right – I just guessed that it was anodised seeing the difference in matt (original) and glossy (scratched) areas.

    So it sounds like I could try the varying grades of Garryson Aluminium Oxide Abrasive Blocks? Same idea as wet and dry?

    Will the scratches/worn patches start to look like the brushed satin areas? Then I guess I could use the Autosol?

    Sticker idea is a good shout if my efforts totally ruin it 🙂

    molgrips
    Free Member

    Paint…

    wobbliscott
    Free Member

    Wet and dry will get the scratches out easily and quickly. Aluminium is really really soft. The colour change will probably be to oxididisation. I doubt it will be anodized (I’d be surprised). It’s an airline cart, they need to be really really cheap and anodizing is expensive.

    marko75
    Free Member

    Can you do a resistance check before and after light polishing with sandpaper? if its anodised then then the resistance will remain the same (unless you go through the anodised) whereas there will be only a slight reduction in resistance if you polish pure aluminium (you will remove the oxide film).

    Caustic soda etches Al (attacks it) but will not touch anodise (Al2O3) so don’t leave submerged in it over night but dab it or submerge it for minutes at a time. If you remove the surface of the Al with caustic then you might be able to remove the scratches that way

    Good luck!

    Jolsa
    Full Member

    Thanks for all comments, think my next step will be to test the various grades of Garryson abrasive blocks on a section somewhere, and see how it blends the scratches out, and if the resulting finish looks wildly different to the surrounding bits.

    Don’t want to get caught in the spiral of overdoing a section and having to go over the whole cart frame to match.

    Get this part out of the way so I can concentrate on spray painting the panels (thread revival in ten years!) 🙂


    RaveyDavey
    Free Member

    That’s definitely treated in some way. Doesn’t look like anodising though, maybe electrostatic sprayed? Aerospace parts are highly unlikely to be left in a raw state, even something as basic as a cart.

    Greybeard
    Free Member

    You may be better with wet & dry paper than abrasive blocks. The blocks will only contact the high spots, so you will eventually get a flat and uniform finish, but it will take much longer than using paper that follows the contours and gets a uniform finish without having to be 100% flat. Whichever, keep all the movement in the same direction.

    brocks
    Free Member

    Try your local bead blasting company they may be able to help.

    cbike
    Free Member

    I’d use it as a tool box.

    takisawa2
    Full Member

    Looks anodised.
    Either way, one of those BBQ cleaning brushes, with the brass bristles, should at least give you a uniform finish. Then a course scotchbrite pad to smooth it out a bit more.
    If you get it re-anodised they would etch the surface back anyway but it won’t be cheap.

    globalti
    Free Member

    I’ve just remembered that I know a South African guy who re-finishes and restores airline carts and catering equipment at Johannesburg airport. Have emailed him for advice on the finish and the best way to polish it up.

    Back soon.

    Jolsa
    Full Member

    globalti – very kind of you, thank you! Sounds like the perfect person to ask.

    andyl
    Free Member

    soda blast it to a nice texture?

    globalti
    Free Member

    I’ve saved the two pics above and emailed them. Back soon with suggestions.

    globalti
    Free Member

    It will be Wednesday as South Africans are all out lighting their barbecues now.

    Jolsa
    Full Member

    Great, thanks for asking him globalti.

    Thanks for other suggestions, soda blasting looks fun but I’d rather start by exploring options that take elbow grease and time than buying more kit.

    Not looking for a perfect finish, just to equal out the brushed/anodised/electrostatic sprayed/whatever it is areas with the bits that have worn over the years revealing the shiny metal underneath.

    If nothing really does the trick, then I’ll decide it’s an aesthetically pleasing patina that I wanted to keep!

    globalti
    Free Member

    You are on the right track; I’m afraid his reply, just received, doesn’t help much:

    “From the pictures that you send it looks like the trolley might be anodised.
    The trolley can be stripped but is not really necessary to do so if you want to paint it as for the aluminium extrusions to remove the dents and deep scrapes the extrusions would have to be replaced.
    Please take note that if the trolleys are used on an aircraft the paint must be approved for aviation?”

Viewing 27 posts - 1 through 27 (of 27 total)

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