Aluminum question

Discussion in 'General Slingshot Discussions' started by codido187, Jan 15, 2014.

  1. codido187

    codido187 New Member

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    Ok when I start getting my crucible hot enough the aluminum cans in melting don't melt it starts turning into liquid and doesn't go past that it turns almost into flaky liquid substance. Where might I be going wrong my forge is hooked up to a blow dryer and I've turned iron bright orange close to white to where I can shape it freely. Any ideas
     
  2. BeMahoney

    BeMahoney Builder of things

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    Aluminum oxide has a melting point of 2300°C..
    Depending on the thickness of your material (cans?) you might have
    a rather high amount of that? Did you take a magnet to check if
    there´s no iron in there?- Ask theartofweapons.. he incidentially
    "invented" thermite ;) ... And that thermite invented heat!
    and burned his crucible +...

    Be
     

  3. codido187

    codido187 New Member

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    They're very thin cans an no a magnet doesn't stick to it. And it started melting it but I dot know what's stopping it my forge gets really hot I can work thick rebar into shapes my crucible is a paint can. And I heard about that lol Jesus is that dangerous I may just stick to hdpe
     
  4. Obl1v1Aus

    Obl1v1Aus Meh!

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    I remember someone saying that aluminium cans are a pain to melt because they are so thin, I think TAOW had a video of him using Aluminium foil that he had to fold repeatedly and hammer into a larger mass so it would melt (I'm pretty sure it was TAOW, apologies if I'm wrong).
    You might have to try that
     
  5. buckshot500

    buckshot500 Hoonigan Jeeper

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    I think you need some kind of flux.

    My googling has led me to think Borax or "Lite" salt or even a small handful of limestone can help.

    It is not supposed to be necessary for a flux to be used though for home casting of aluminum. I think you might want to try flux though, if you really want to cast aluminum and can't get the results you want using no flux.

    Here is a helpful link I got from dangster;
    http://www.backyardmetalcasting.com/

    Here is another link I found;
    http://foundry101.com/archive.htm
     
    Last edited: Jan 15, 2014
  6. codido187

    codido187 New Member

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    Hey thanks for all the help guys I'm going to check it out and see what I can do to melt ill use foil I think aluminum cans do not melt what so ever
     
  7. buckshot500

    buckshot500 Hoonigan Jeeper

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    I just thought of something else that might be at work here.

    If the heat is not transferring to the cans properly, maybe the crucible is too hot. in other words the metal is so hot by the time it melts, it's just burning up. Try putting the cans in the crucible with the heat on your crucible. When it seems hot enough, maybe try hitting the cans with a propane torch to initiate melting. Once there is some melted metal, the rest of the cans might melt easier into it.

    Also there will be a thick layer of slag/oxides and very small amounts of melted metal until many cans are melted.

    Also there are many sources of aluminum besides cans and foil. Maybe thicker chunks is all you need.
     
  8. Obl1v1Aus

    Obl1v1Aus Meh!

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    I asked my dad about this as he has was working with aluminium in his last job.
    Cans do melt but as BeMahony said the aluminium oxide layer has an incredibly high melting point, but the aluminium under the oxide layer melting point is less than half of that. As cans have such thin walls there is more oxide than pure aluminium.

    If your going to use foil you will have the same problem, here the link to theartofweapons video i was talking about

    [ame]http://youtu.be/SlKV_ALrcnQ[/ame]
     
  9. codido187

    codido187 New Member

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    Thanks I appreciate I will study it I was so upset I was making like a slurry almost
     
  10. codido187

    codido187 New Member

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    Thank you guys for yor help hopefully I'll get some spare time to melt some foil
     
  11. yep in the past i have cast some foil but again it is kind of expensive to get a slingshots worth of foil so you can also use cans and i have been experimenting with them lots recently and i find that it works best if you beat them really flat with a hammer so that there is less air and then less chance to form aluminium oxide. it also helps if you melt some other aluminium in a crucible first because then there is much more surface area against the cans
    you will usually only get about 50% yield from the cans because the rest is all slag and burr
    also i find that the cheapest and easiest way to get aluminium is just to go to a local scrap metal yard (got loads where i live) and just ask for some scrap and tell them what it is for
    i went the other day with a slingshot to show them and they just said "we have 5 tons of the stuff so you can have what you like" took enough to make a few slings and to them that is worth nothing
    i have got a casting tutorial here but a much better one is coming out this weekend
    [ame]http://www.youtube.com/watch?v=WfI7oA1VY78[/ame]
     
  12. Slagskimmer Mike

    Slagskimmer Mike thinks TBG smells better than roses

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    +1 about salvage yards.

    Dead automatic transmission from pickup truck + sledgehammer and safety glasses = many chunks of lovely cast aluminum, with byproducts of sweat and maniacal laughter.

    Please be safe with this stuff, many things explode instantly at temperatures high enough to cast with, showering molten metal down on you...
     
  13. Alukuchen

    Alukuchen Senior Member

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    i think what will help is to melt some other pieces of more solid aluminium in your crucible and then push the cans into the already molten metal. Worked for me :)
     
  14. codido187

    codido187 New Member

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    Thank to guys for the advice I do appreciate it.


    Taow could you please tell what kind of forge you had how did you make the crucible what is it made of. And is that a gas forge???
     
  15. codido187

    codido187 New Member

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    Lol I'm going to my scrap yard to pick up some aluminum next week
     
  16. buckshot500

    buckshot500 Hoonigan Jeeper

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    I'm one of those guys who tends to add/display info if i feel it might be relevant to something that is going on in the thread. in TAOW's video, he had a problem with large voids in the underside of his cast fork.

    There is a product called "Lumniweld" that is basically a solder for aluminum. I don't think it even needs flux although the base area should be cleaned first. You use a propane plumber's torch to heat the base metal just enough to feed the lumniweld rod into the void or crack and weld it up.

    I've seen a vid that he made (after this one) that turned out much better, but Lumniweld is good to have around when working with aluminum.
     
  17. codido187

    codido187 New Member

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    That's pretty cool to learn. And also I can get a 4inch pipe about 2ft long with a welded cap would that work as a crucible???
     
  18. buckshot500

    buckshot500 Hoonigan Jeeper

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    Aluminum melts at a much lower temp than steel does. Most electric kilns can be set to an exact temp to avoid overheating.

    A coal forge can easily get temps high enough to melt the steel pipe crucible. Some care could be taken to ensue the crucible doesn't get so hot it starts to melt too.

    All in all, it should work fine
     
  19. Obl1v1Aus

    Obl1v1Aus Meh!

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    +1 for Lumniweld, that stuff is awesome. I've patched a holes in my Utes Tray with that stuff, you do need to clean it with a stainless steel wire brush first.
    And its damn strong too!, Bloody expensive to get here though
     
  20. I will have to give some of that stuff a go!
    Also I was using a coal forge with a graphite crucible that I got off eBay
    Have fun casting and post pics of your sucsess or failire! :)

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