DIY Aluminum Bronze. One of the Hardest Bronzes

For one of future projects I need some hard bronze, that's why I decided to make Aluminum Bronze. This bronze is one of the hardest!

Step 1: Bronze Content

This bronze will consist of 88% of copper and 12% of aluminum. Melting process is simple. At first I need to melt copper. So when I reach the temperature 1100-1200 C, I'll add aluminium. Finally, I suppose to get 2 kg of hard aluminum bronze.

Step 2: Copper Started Melting

When copper started melting it's time to add more copper and after that aluminum.

Step 3: Casting Time

Metals were melted and mixed. Casting time...

Step 4: The Quality

The quality of the round bar is not very good. There are some pores inside (in the centre). The second ingot is fine.

Step 5: Cutting the Upper Part

Cutting the upper part to see pores.

Step 6: Weight and Hardeness

I've made 2 kg (4.4 lbs) of aluminum bronze which I'd use for some projects. After processing on the lathe it's easier to see pores. This grade of bronze is really hard.

Step 7: Crucible

The crucible was damaged because the temperature was too high. Anyway the work was done. Some time ago I've already made Lead Bronze (it's on the right on the photo, push the link to read) and it's completely opposite to this one.

Comments

[jlcollier1999]

Why not use the aluminum to dissolve the copper? Wouldn’t that require less temperature? Or does copper not soluble in liquid Al? I know a lot of metals are.

[DuralM]

I don't know if it can help to do the job faster. I mean sure aluminum will melt when you reach 660 C but you need to get 1200-1300 for the copper. From one side molten aluminum will allow to have a better contact between hot crucible walls and copper and from the other side you need to heat more metal from the beginning. So I`m not sure if it can help somehow.

[malcolm buehler]

Where did you get the copper? I've been trying to find old motors to scrap, but I haven't had much luck

[DuralM]

Oh. It was mine. I don't have much ;)

[fredlam]

What is the crucible made of?

[DuralM]

It was made of stainless steel! Therefore its melting temperature must be 100-200 C higher than cheap grade carbon steel. Now I started to use graphite crucible.

[fredlam]

Thanks.

[DuralM]

You're welcome :)

[gm280]

I watch a lot of smelting and pours all the time. And one thing I don't see much of is fluxing the liquid metals before pouring. I melt tons of lead and make ingots from that. And I always flux the metal with some sort of wax. Be it a candle, crayon or what ever I have. I flux the liquid lead and it allows more of the slang that floats on the top, mix back into the lead to yield a much stronger finished pour. But I don't see anybody doing the fluxing with aluminum or copper. Why not? I believe it would also help with reducing metal separation when melting. Just wondering.

[DuralM]

It's always a good idea to use some flux. I use borax for brass, copper and bronze. And salt for aluminum. I don't remember if I used it this time but when I want to get a good quality I always use some fluxes. I think a lot of people use fluxes that's just not always on camera or in a text :)

[kickinit233]

Very cool aluminum bronze is on of my favorite metals only behind durilium and beryllium copper.

[DuralM]

Yes. I completely agree. It's enough cheep alloy which has awesome technical characteristics!

[DIY Hacks and How Tos]

Very impressive.

[DuralM]

Thank you. I will use this bronze for some cool projects :)

[Lorddrake]

the 88:12 ratio .. is that by weight or by volume?

[DuralM]

Hi. That's by weight.