Thursday, April 17, 2014

Melting Scrap Aluminum for Bike Shift Levers

Tuesday was my second day using the flower pot furnace to melt all sorts of scrap aluminum in preparation for producing our Bike Shift Levers. These bike shift levers have only six parts and are designed for the needs of people who rely on their bikes every day. Two of the parts need to be cast from scrap aluminum so these shifters can be made anywhere in the world, even places without electricity.

We're still waiting for a machinist to make the first permanent mold, but in the meantime I get to learn all about melting this lovely stuff.
Here's my latest set up for the furnace. I started with a hand pump which worked great, but as a one gal operation I had a hard time keeping the air flow going and feeding the crucible with scrap. The hairdryer was magic!
This was the batch of window frames and other channel aluminum donated by one of my tennis buddies. I also did a batch of just bike parts, mostly cast. You should have seen the crank arms disappear! They were like ice melting in hot water, except the water is this gorgeous silver liquid, mmmmm....
Here's a shot of the crucible full of that silvery liquid and ready to pour.
And here's one of the batches poured into a cupcake pan to make ingots. I did four batches like this in three hours. The other two batches were a mix of lighting fixtures, cookware and other aluminum odds and ends. My earlier batch was all cans. I marked each ingot with its basic content so I can mix thin material with thick to increase the quality when I pour them into the mold. Each of these ingots contains enough aluminum for two shift levers when I remelt them.

I don't have to make ingots first, but it's a great way to learn the furnace, reduce the massive scrap pile I've accumulated and have fun with this mesmerizing stuff.

Stay tuned because I should have our mold later this spring and get to post photos of our first shift levers.


  1. I'm curious... why are you stuck on investment molds?
    Wouldn't you open up more possibilities for folx to develop economically by teaching them sand molding techniques?

  2. This is certainly an option for folks who only want to make only a few. But sand casting gets mighty tedious when you try to step up production of the same part. It works great for massive foundries with lots of workers, but for small operations a permanent mold will be a much shorter learning curve (only have to learn how to melt the scrap) and get them into production much quicker.

    Our manual will cover all of this and will encourage folks to look into expanding their foundry. If sand casting looks interesting to them, especially if they want to take on other jobs, we certainly encourage it.


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