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  • Metal treatment/ coating.
  • Ambrose
    Full Member

    I work as a science teacher and as a project over half term I’ve decided to renovate the very old and rusty retort stands in my lab. The bases are cast iron, the uprights are mild steel bar, threaded into the bases.

    Step 1- dismantle
    Step 2- dishwash the bases to remove candlewax, sticky gunge, blu tac/ general horrid stuff. Done whilst MrsAmbrose is out of the house.
    Step 3- wire brush on angle grinder, take all bits back to shiny bare metal.

    Top tip #1 Wear suitable PPE. I ended up with a bit of wire embedded in my forearm.

    Step 4- Paint bases with Hammerite. Wait 48 hrs. Repaint.

    Top tip #2 Do not use Hammerite in a small shed on a hot day. Nor the solvent for cleaning the brushes.

    Stem 5- Ask STW how to coat/ treat the steel uprights in such a way that the users won’t get covered in oil/ cack/ gunge, will remain clean and safe and will hopefully ensure that the stands don’t get rusty.

    The steel bar will have clamps attached using screw fittings. These will easily break through any paint or lacquer. Previously we have purchased chrome plated stands which have proved to be nasty things- the chrome gets damaged, the rust forms, the chrome blisters off, the users get filthy and cut on the sharp edges from the plating.

    I have come up with a possible answer-

    Electroplate with copper, just a very thin layer. The bars are quite long but I suppose that they could fit into a bath made from a long thin plant pot holder thingy. I can get loads of copper sulfate from work.

    Any suggestions?

    http://www.philipharris.co.uk/products/lab-equipment/lab-essentials/retort-stands-accessories#resultspage,1|resultsperpage,10000|
    Wipe down with a wax of some kind.

    maccruiskeen
    Full Member

    Step 3- wire brush on angle grinder, take all bits back to shiny bare metal.

    Step 3a – spend hours extracting a 1000 crimped wire pubes from your clothes / hair / teeth / socks / bum crack

    Step 11f – continue finding wire pubes for months and years afterwards

    Ambrose
    Full Member

    Tell m e about it. Also embedded in the nice interlocking foam matting on the bike shed floor. I have a feeling that that is a mistake that will come back to haunt me no matter how well I sweep up.

    jonba
    Free Member

    Paint won’t really work for the reasons you mention. Copper electroplate would be an interesting experiment but it too will get scratched off. I’d suggest you try a more reactive metal, that way even if it gets damaged it offers cathodic protection. Zinc being the obvious choice. I don’t think electroplating or hot dip galvenising are something the enthusiastic amateur can do but google suggests you can plate in other ways. You could probably knock this kit up yourself?

    http://gaterosplating.co.uk/Zinc-Plating-kit.php

    maccruiskeen
    Full Member

    do the stands get hot in use? – heated galvanised steel can give off some pretty unpleasant fumes

    timba
    Free Member

    Temper and quench in oil??

    Ambrose
    Full Member

    The stands may well get hot. Combine Bunsen burners, teenagers and absolutely anything else you care to think of- things will get hot.

    Timba- I’ve been thinking about that too.

    Ambrose
    Full Member

    jonba- I’d thought about plating in a more reactive metal as you suggest- but cannot think of doing it at home. Zinc seems the metal of choice though, we have one or two Zn plated pieces of equipment.

    RustyNissanPrairie
    Full Member

    Zinc or nickel plated – professionally.

    Paragon Enamel for the base (Hammershite is crap)

    Ambrose
    Full Member

    RNP- I wish I’d known earlier, such is life eh?

    Bookmarked for future reference.

    motivforz
    Free Member

    If it were something of mine in the garage I would just oil and put up with greasy hands, but I realise that’s not great for a classroom.

    What about black oxide by heating the stands up and dipping in oil? Gives you a coating like a wok, not hugely durable, but slightly malleable and easy to reapply, and isn’t very sticky. Good excuse to buy a blow torch or use the hearth in the D&T class!

    http://www.practicalmachinist.com/vb/general-archive/oil-blackening-rust

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