Making Aluminum Bronze: Melting Copper and Aluminum

28,725

203

48

Introduction: Making Aluminum Bronze: Melting Copper and Aluminum

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

Be the First to Share

    Recommendations

    • Stone, Concrete, Cement Challenge

      Stone, Concrete, Cement Challenge
    • Fandom Contest

      Fandom Contest
    • Fruit and Veggies Speed Challenge

      Fruit and Veggies Speed Challenge

    48 Comments

    0
    johnnymercer74
    johnnymercer74

    Question 3 months ago

    Firstly, this is absolutely awesome so I take my hat off to you! I'm a complete novice and am about to try my first cast in aluminium bronze. Apologies if you've stated this somewhere and I've missed it but:

    Is there a set order to add the material (i.e. all the ali first and then all the copper).

    What did you use for buffing? I couldn't see the video you referred to at the end of Video 2.

    Thanks again and keep up the good work!

    0
    matt.e.jenkins
    matt.e.jenkins

    Answer 3 months ago

    Hello, thanks for the question. It has been a while since I have melted anything since I have burnt out my furnaces. I need to build a new one.
    As for the order, it probably doesn't matter too much. I have heard a few contrary views on it. Melting them together would make the aluminum melt first which may lower the copper's melting point (I do not know if that really works that way). I would either heat them together or the copper first, then add the aluminum. What matters is that they are well mixed. I got some buffing wheels for my angle grinder from Harbor Freight. I think Menards sells them too. (in the midwest USA). I have also ordered a small sanding disk with high-grade grit that attaches to an electric drill. That seems to work too. Then gave it a polish with a buffing wheel with the appropriate compound. I hope this helps.

    0
    johnnymercer74
    johnnymercer74

    Reply 3 months ago

    Thanks Matt, you're a star. Good luck with whatever you're doing now.

    0
    rchrd.brl
    rchrd.brl

    5 months ago

    Beauty may be only skin deep - Beware - - I had? a large cresent wrench made of a material that is Gold colored and non magnetic? - i have often wondered what alloy it is - it fits all of the attributes mentioned for Aluminum Bronze - i was using it in the farm yard to repair a bulldozer when the wrench was lost - i searched for it with a metal detector to no avail - later while tending the farm i found it broken in half by the tiller, a crystaline break similar to cast iron - it breaks rather than bends, though is quite strong - a friend who repairs refrigeration equipment complains often about the copper alloys used in modern refrigeration equipment - He claims that the alloys corrode and do not last as long as the plain copper, previously used - they resemble and could be a type of Aluminum Bronze - perhaps there is room for improvment?

    0
    Durgin
    Durgin

    Question 7 months ago on Step 1

    Any issues with unmixed metal after pouring it? I'm trying to make red brass and it looks like a swirl of metals that didn't mix right

    0
    matt.e.jenkins
    matt.e.jenkins

    Answer 7 months ago

    Hello, I try to make sure it is well mixed. I haven't dealt with that problem, but I know others who have. I use a stainless steel spoon to stir it up before I pour it. I believe that is the only trick. What recipe are you using for red brass?

    0
    graymachine
    graymachine

    Tip 2 years ago

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

    0
    matt.e.jenkins
    matt.e.jenkins

    Reply 2 years 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.

    0
    johnip4
    johnip4

    Reply 1 year ago

    The wool I picked for a forge supposedly will dissolve in water,(or your blood) so it won’t stay in your lungs and cause damage.

    0
    Edgar
    Edgar

    2 years ago

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

    0
    matt.e.jenkins
    matt.e.jenkins

    Reply 2 years 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.

    0
    Edgar
    Edgar

    Reply 1 year ago

    You're welcome. I just do not know it took 6 months for Instructables to warn me of your comment!

    0
    Edgar
    Edgar

    Reply 1 year ago

    Worse, it just jumbled your few seconds comment with other 6 and 8 month's ago!

    1
    woodchipwilbur
    woodchipwilbur

    2 years 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?

    0
    dragon flyer
    dragon flyer

    Reply 2 years 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!

    0
    matt.e.jenkins
    matt.e.jenkins

    Reply 2 years 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

    0
    woodchipwilbur
    woodchipwilbur

    Reply 2 years 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!

    0
    optimalcolt
    optimalcolt

    2 years ago

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