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Thread: Removing two metal plates bonded together by epoxy ?

  1. #21
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    Quote Originally Posted by hobbybob View Post
    It worked. I thought it was epoxy but it was soldered !
    I heated it with a blowtorch i picked up at the local hardwarestore.
    just like 20-30 seconds, screwdriver in a slot and i was able to move it from eachother easily and then i noticed it was just some sort soldering (looked like silver!).
    Ok, just to be perverse, I'm going to ask people how you'd put that back together.
    I'm interested because apart from silver-loaded epoxy I don't know how a strong thermal and physical bond between aluminium and copper plates can be made. I tried messing with stuff called HTS2000, a 'brazing' alloy that can bond them, but the mess is terrible because the resultant aluminium alloy has a lower melting point that the aluminium substrate so the whole thing collapses like a hot wet sponge! It's not easy to make HTS2000 meld either, you have to literally scrub it onto the surface, so when the substrate collapses, great gouges result in the surface. I had hopes that a fast heating of powdered HTS2000 alloy with a flux might allow a bond to form before the surface of the aluminium dissolved the alloy and collapsed, but I never found a flux that worked.

    The reason for putting Cu onto Al is that a thin Cu layer can be easily used to mount other parts by solders of varying melting points onto a cheap Al heatsink or other form to make cheap and stable small optics systems. Big ones would suffer from thermal bimetallic action but a thin Cu on thick Al ought to be ok for many small DIY projects like beam combining.

  2. #22
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    "liquidized chemical metal"
    Hardens when in contact with oxygen, can be obtained with varying temperature tolerance. Very handy, very expensive.

  3. #23
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    Got any linkage to details? I Googled for "liquidized chemical metal" (and tried liquidised too) but got no results. I get lots of results if I omit the quotes but then I get so much noise I can't find a signal..

    Another difficulty I have with this is that if the bond is formed from something that needs oxygen, it quickly becomes a very anaerobic location sandwiched between two metal plates. Using the oxide layer on the aluminium would be nice but there's not much oxygen there. Worse, it's VERY firmly bonded so anything aggressive enough to use it will take to the point of saturation from free air and become useless long before I got it spead between two plates of metal. Not saying this is what happens, just how the problem appears to me... I'm also not sure how this stuff might become a metal bond that desolders with simple heating as hobbybob describes it. In other words, I really don't understand this 'chemical metal' bit.

  4. #24
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    My next door neighbour buys it, he's a metalurgist although he buys it priovately for himself not through any trade contacts.

    Its very hard to find these days as technically its chemical metal but Plastic Padding have adopted the name for their fibreglass compound so a google search usually brings up fibre glass epoxy compounds and not true chemical metal which as Occularis says is actually a metal in a tube that you can squeeze out onto joins where it then sets into a true metal joint. Its very hand for repairs where something has broken away on a vital part because you can put a blob on, let it set, then grind it down to shape.

  5. #25
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    I am not sure how to remove it but I know how to bond it.

    I have some aerospace grade epoxy for bonding composite materials to metals (aluminum) to carbon fiber. Using some extra I bonded two sheets of .035' alu to each other. I tore the alu before the epoxy let go. It is locktite Hysol 5XXX something.

    Totally amazing.

    Chad


    When the going gets weird, the weird turn pro.


  6. #26
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    maybe electroplating copper on the aluminium with a CuSO4 solution would work? If so, it would be useful to electroplate zinc on it beforehands, or the copper wouldn't stick on the Al - just an idea

    then you could perhaps solder a copper plate on the copper-plated Al by heating them to the correct temperature and adding flux

  7. #27
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    Hmm, yeah. The Plastic padding chemical metal is not what I meant, although that stuff is very good as well. However their product can be used to fix holes in materials that are exposed to several hundred degrees C of heat (engine parts and such) without dissolving. Unfortunately I dont have any reference to the stuff I posted, just remember the stuff since it was so puzzling to me how it worked.

    These might have something useful:

    http://www.itw-devcon.co.uk/index.ph...con_adhesives/

    http://www.nch.com/europe/section.as...ID_SECTION=191
    Last edited by Occularis; 03-26-2010 at 04:13. Reason: added links

  8. #28
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    Thankyou all, that's good reading. I like the electroplating idea, I don't know what the best and firmest order of events (and metals) is but laying down directly to Al resulting in a secure Cu surface is ideal, if I can get it. (Basically, is Al-Zn-Cu enough to do this solidly, if not, any other method to use?)

    White-light, any chance your neighbour might reveal more? This stuff sounds interesting, I'm definitely not after a metal-loaded epoxy, I can already get those, the thing I'm most curious about is whether this 'chemical metal' results in a true metal bond between Al and Cu that can later be unsoldered as hobbybob describes. If that really is what results, it's very weird, because there is surely some other element(s) involved in the business, and I have to wonder what they are, and where they go. If they vanish from between two plates of Al and Cu it begins to look like alchemy.

  9. #29
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    It's no pesky alchemy, it's magic!

  10. #30
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    Occularis had the right people, Devcon is the place to go.

    Here's a link direct to the liquid metal putty page. Just hover over the "products" heading to get a pop up list of all the putties available.

    There are several designed for different products / strength of joints eg Aluminium, Stainless, Titanium, bronze, metal, underwater etc

    Link: http://www.devcon.com/products/produ...tal%20Surfaces

    There's also another company called bezola but I'm dammed if I can find them!

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