Making Aluminum Bronze: Melting Copper and Aluminum

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About: I live in Minnesota, USA. I've been a Maker hobbyist for many years. It's fun to be Geeky.

Aluminium bronze is a type of bronze in which aluminium is the main alloying metal added to copper, in contrast to standard bronze (copper and tin) or brass (copper and zinc). A variety of aluminium bronzes of differing compositions have found industrial use, with most ranging from 5% to 11% aluminium by weight, the remaining mass being copper. The alloy I made consists of 11% aluminum and 89% copper. I personally made these just for the joy of creating and learning how to make alloys. If you have the resources to safely melt metal, then give this a try.

These videos show the process I used. The first video shows the test to see if it worked. The second and third video show the process of casting an ingot in sand to make a larger batch of beautiful bronze ingots. More details are in the following steps. For more videos like these and other DIY Projects click here.

Step 1: Unique Properties and Uses

Unique Properties:

  • High Strength
  • Very Hard
  • Corrosion Resistance
  • Tarnish Resistant
  • Low Reactivity with Sulfurous Compounds
  • Biostatic (stops microorganisms from reproducing)
  • Golden Color

Uses:

  • Coins (20, 200 and 500 Italian Lire, 10 Philippine peso coin on the inner ring, the one and two dollar coins of Australian and New Zealand currency produced by the Royal Australian Mint, and some Mexican coins)
  • Bearings
  • Landing Gear for Aircraft
  • Boat Propellers
  • Jewelry
  • Tools
  • Art
  • Pipes and Parts Used with Salt Water

Step 2: Gather Materials

What is needed:

  • Metal Foundry or access to one (I made my home foundry)
  • Crucible (Large enough to handle what you need)
  • Heat Source (I use propane and a homemade torch)
  • Copper
  • Aluminum
  • Mold that Can Take The Heat (most are made from steel, graphite, plaster, or green sand)
  • Kitchen Scale
  • Tools to Handle Molten Metal +2000 deg F.

Safety:

  • This is incredibly dangerous. This material is literally hotter than lava. You will need proper clothing, heat resistant gloves, face shield, and a safe place to work. Since I made these videos, I made proper tools to handle the crucible.

Where to get Free Metal:

  • Aluminum: (Try to stick a magnet to it. If the magnet attracts, then it is a type of steel. If the magnet is not attracted and it's relatively light feeling, then it is probably Aluminum.)
    • Disposable Trays
    • Hard Drive Cases
    • Computer Heatsinks
    • Old Lawn Chairs
    • Pans and Kitchen Utensils
    • Wires
    • Old Tube TV's
  • Copper:
    • Ask friends if they have scrap copper from electrical work or plumbing.
    • Electrical Wire
    • Pipes
    • Old tube TV's
    • Microwaves
    • Electrical Transformers

Step 3: A Beautiful Aluminum Bronze Bar

Here are some examples of the Aluminum Bronze bars I have made. I gave half away as gifts with stamped custom messages on them. They could be remelted and casted into unique objects by the process of sand casting, lost-foam casting, or lost-wax casting.

Step 4: Contact Me

Thank you for viewing this project. When done safely this project is very fun and rewarding. Feel free to comment and/or send me a message and I will do my best to reply.

For more videos of ingot making or other DIY projects, check out and subscribe to my YouTube channel.

YouTube: GeekGuyMJ DIY Projects & More

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    39 Discussions

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    woodchipwilbur

    4 months ago

    1: In my foundry course, I was always taught to melt the higher melting point component first - and then add the lower mp one. Is there a reason for doing it the other way round? Was my foundry teacher wrong?

    2: I see in a comment above, makingboat tells about cooling quickly. What does the thermal shock effect have on the structure of this alloy? I cast bells (80%Cu, 20%Sn) and the slower you cool it the better. I leave the casing in the sand till it is cool enough to touch - dropping it into a pan of water brought tears to the eyes!

    3: Were you actually surprised that you set your bench on fire?

    3 replies
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    dragon flyerwoodchipwilbur

    Reply 4 months ago

    I laughed when I noted your query re which component to melt first. Not because I have or am ever likely to melt any quantity of metal, but because I very recently figured out this concept in the context of melting chocolate! I like to mix dark and milk chocolate for goodie making, which you do over hot water, and was having trouble getting a smooth mixture. It finally dawned on me the dark chocolate has a higher melting temperature, and if I melt the milk chocolate first, it never gets hot enough to melt the last bits of dark chocolate...

    So delightful to discover concepts that are applicable for different purposes!

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    matt.e.jenkinswoodchipwilbur

    Reply 4 months ago

    Hello,
    1. I was going from what I was told, but I have not had any formal training on the matter. So, I would go from what your teachers said. The only thing that made sense to me was to get the lower temp metal melted first, then when the higher temp metal is dropped in, the whole surface area would be covered and heat it that much faster. But then again, I don't know what I'm talking about :-) That could be way off.
    2. I would love to cast bronze bells. One day I'm trying that. I believe water or oil quenching or not quenching, but air cooling all help with bringing out different qualities in your metal. I found some info here: http://www.nationalbronze.com/News/important-featu...
    3. I figured it would, but was surprised by how quickly it did. That is why I usually put my molds in a tray of sand.
    Thanks for watching

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    woodchipwilburmatt.e.jenkins

    Reply 4 months ago

    That's like the endless English discussion about whether to pour the milk first or the tea! The rationale I was given runs like this...
    If you melt the lower MP metal first, even though you get better thermal transfer, you still have to heat that metal way above its melting point (Al 660 - Sn 232) and approach its boiling point (Al 2467 - Sn 2600) in order to start melting the copper (1084). Well before that point (we'd never get there in a small furnace) that metal will begin to evaporate - and that is going significantly to alter the proportion of the two metals. If you heat the copper first, you are making a larger volume of liquid at a temperature that is already hot enough to melt the smaller amount of the lower MP metal. Putting the relatively cold copper into a smaller volume of over-heated Al or Sn will immediately cool it again.
    Yes; it is harder to do the initial melt. But you'll lose less tin (or aluminium) if you put it in second - and if (as your video seems to suggest) you are working indoors for at least part of this process, you are less likely to kill yourself with the metal fumes!
    Don't ignore the safety! Some more PSE gear would be useful - and do set up extraction facilities if you are pouring indoors. You are worth it!

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    Edgar

    4 months ago

    Melting Metal.... Mmmmmm... (Homer Simpson impersonation) Great Videos!

    2 replies
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    matt.e.jenkinsEdgar

    Reply 4 months ago

    Thanks Edgar! There is something satisfying about melting and pouring metal. Last night I made an almost 8lb brass ingot from plumbing parts. The video will be on my youtube channel soon. Thanks for watching.

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    optimalcolt

    5 months ago

    Make A knife out of it!!! Also how much is the sanding disc set?

    2 replies
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    Saeromatt.e.jenkins

    Reply 4 months ago

    Agreed, even best grade titanium is incomparable to a hardened mid carbon steel.

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    JamesA41

    4 months ago

    Wow... totally awesome timing to email this out! I was thinking two nights ago before I went to bed about casting projects since I was planning on recycling some aluminum for electronics modules cases and while at it making some practical items like door handles. This got me thinking about nutrients since I get disturbed manganese is so high in some supplements and why not more Magnesium (especially if you're not eating enough green vegi's). This turned into me wondering about Magnesium having the oligiodynamic effect as well as how would Magnesium and Copper alloys for handles and other systems from the perspective of human nutrient balance requirements mix and form. Would magnesium stabilize and not burn off in a lower melting point copper zinc melt or would it ignite? What ratios can be obtained?

    Thanks for the great timing reminder to write this down and look into further.

    2 replies
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    matt.e.jenkinsJamesA41

    Reply 4 months ago

    Hello and thanks for watching.
    I don't know about the nutrient effects, but the whole idea of the oligodynamic effect is very interesting. I can't say for sure about MG burning, but that I the reason I don't want to burn MG in my hobby foundry.

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    JamesA41matt.e.jenkins

    Reply 4 months ago

    Hi, thanks for producing the instructable... I needed the extra inspiration to move forward with my idea. I have experience with tig welding aluminum and magnesium alloys from back in high school since I wound up getting ahead of the class and started doing advanced work and government jobs (as they were called). We were warned that the magnesium alloys can run away or something like that as I later learned about magnesium ribbons and thermite in college. I think most the alloys I welded were higher concentration of aluminum and the surface area to exothermic effect wasn't so high.

    Anywho... yeah... the nutrient idea was something I was thinking about since I advocate bio-equivalent health also. I'll have to read into and research to see if there is any data already and keep this thread and others posted when I get around to.

    Oligodynamic effect is interesting also when human nutrients especially or maybe silver since not toxic as much. More of a concern when heavy metals that are poisonous. Thanks again... keep us posted! Neat project.

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    graymachine

    Tip 4 months ago

    That uncoated kaowool layer between your furnace and its lid is a short road to severe lung disease.

    1 reply
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    matt.e.jenkinsgraymachine

    Reply 4 months ago

    Yes, I was concerned about that. I don't use it any longer, but the kind I had claimed the fibers being realised were less of an issue (I don't remember why). But I still stopped using it and use a respirator.

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    Bverysharp

    Question 5 months ago on Step 4

    Interesting, very smooth finish on the ingots. I do a little bit of brass casting into greensand, but the finish is nothing like this. What did you cast the metal into?
    Also, what has caused the small voids all over the surface?

    3 answers
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    matt.e.jenkinsBverysharp

    Answer 5 months ago

    Hello, it was casted into homemade greensand. A mixture of 90% filtered play sand (finer the better) and 10% ground natural kittie litter. With a bit of water to help it bind. But the polish was with an angle grinder. I got a polishing set of “grinding disks” from Harbor Freight. It goes up to 600 grit. Hope that helps.

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    JamesA41matt.e.jenkins

    Reply 4 months ago

    Neat, you've found natural kitty litter as a clay source also. The bags of the different types of bentonite aren't really that expensive... until like I realized in my situation there wasn't any local sources for sale and the shipping was well over 10 times as expensive. Next source if there is none to dig up from a local deposit... kitty litter.

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    matt.e.jenkinsJamesA41

    Reply 4 months ago

    That was my same problem! The clay was very pricey to have shipped to my house. Then I found that natural kittle litter is mostly made of the same stuff, and only cost about $2.

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    yrralguthrie

    4 months ago

    What is jewelery?

    When collecting aluminum, be aware that quite a bit of the metal that looks like aluminum isn't. It's is either magnesium or zinc. For one instance and to point to objects that might not be aluminum, many electrical hand tools are made from zinc or magnesium, mostly zinc. If something is made with a die casting it is likely a zinc alloy. Zinc is easier and cheaper to cast. Dies last longer.

    Old car carburetors look like a source for aluminum, but they are generally zinc alloys.