Melting aluminum

http://ericlippert.com/2014/09/12/melting-aluminum/

by eurg • 12 years ago

170 35 12 years ago

Anyone interested in the topic should check out the Gingery series on building your own workshop from scrap, which is all based on aluminium casting

jacquesm4• 12 years ago

He mentions Gingery as an inspiration:

"The project that I am gradually preparing for is to build the Gingery Lathe. The late Dave Gingery wrote a seven-part series of books in which he describes how to build a foundry, lathe, shaper, drill press and other metalworking tools from scrap at a tiny fraction of the cost of buying each. For me it’s not so much the cost savings (or the post-apocalypse skills!) as it is the opportunity to learn for myself how tools work at a fundamental level."

From the comments.

spacemanmatt• 12 years ago

I have watched many chapters of the Gingery lathe casting series, because I have always loved process and tooling and youtube is now FULL of amazing documentary footage. I found it strangely enjoyable to watch.

nraynaud• 12 years ago

One of the big drawbacks for me is the scraping, it's tedious and thankless. I guess that's why older people do it more, they learned patience.

pavel_lishin2• 12 years ago

What is scraping?

InclinedPlane2• 12 years ago

If people find this interesting they might also like the myfordboy channel on youtube: https://www.youtube.com/user/myfordboy

There's tons of material in there on machining and especially metal casting at home.

IshKebab• 12 years ago

Also tubalcain (google it).

ericlippert8• 12 years ago

Indeed, I watched all those youtube channels for quite a long time before deciding to build a foundry; there is excellent stuff out there! The Gingery books are really very good for books, but for a lot of these tasks it is so much more clear to watch someone do the work.

paddy_m• 12 years ago

I'm a huge fan of Keith Fenner https://www.youtube.com/watch?v=kANvdzoVUfw . He takes you all the way through a project.

jacquesm4• 12 years ago

Great article, I love his detailed explanations of why he does things the way he does them (the boots without laces, the natural fibers) when it comes to safety.

Don't be fooled by the low-tech appearance, this guy is top notch, he's been doing a ton of research and has quite a bit of experience. You don't set this up the first time out of the gate like this and if you plan on doing any aluminum casting yourself this would be a great starting point.

I also like how he evaluates what he's done, notices what could be improved and makes notes to do those things better next time. That's how you get to where he's gotten in the first place. There are other aluminum melting tutorials out there that make me cringe.

If anybody is wondering why concrete can explode when heated rapidly, concrete will always contain a percentage of water and when you heat that up faster than the steam can escape from the material it will cause a steam explosion.

ericlippert8• 12 years ago

Thanks for the kind words, I appreciate it. Indeed, I did a lot of research on home foundry setups and tool building before I started this project, and I am deliberately going slowly and carefully.

idlewords• 12 years ago

This was a wonderful post, thank you for taking the time to share it!

One question—I thought aluminum was really reactive with oxygen, and normally ever piece of it we see is coated with a thin film of the oxide. Does this present any special issues when heating it up to melt it?

JacobAldridge• 12 years ago

Just read the entire series (seems he was inspired in the summer of 2012, and recently returned to this backyard project). I found it really engrossing, and as he wrote in his first post, the spirit of hacking with tools outside the metaphorical software application.

aethertap• 12 years ago

Lionel Oliver has put together a great resource for this kind of thing for others who are interested [1]. When I was in high school I built a foundry (basically a stack of bricks with a draft hole and a place to put a small cast iron pot). I used it to melt aluminum and make castings in sand, and it was tons of fun. Looking back, I had no concept of safety at all but amazingly I didn't burn down our chicken coop, which is where it was built. The fuel I used to melt the aluminum was leftover lumber from our house remodel that I cut into cubes, and I had an old double squirrel cage blower set up to provide the draft.

1. backyardmetalcasting.com

arethuza• 12 years ago

Of course, having a bucket of sand handy to put fires out does raise the question as to what would make the sand burn (at least if you are in the habit of reading Things I Won't Work With):

http://pipeline.corante.com/archives/2008/02/26/sand_wont_sa...

octetta• 12 years ago

Nice article. As an unsafe counter-point, a few years ago I came home to my (then) 16 year-old son in the backyard tending to a pit he'd dug, full of a blazing stack of sticks that he was stoking with my leaf blower... sparks flying everywhere. He used this to first melt pennies, then my wife's aluminum cake pans. When I arrived he didn't have a shirt on, because he didn't want to burn his clothes. Ah, youth!

pavel_lishin2• 12 years ago

I used to collect old discarded car batteries, pull out the lead cells, and melt them down over the kitchen stove, and then pour them into glasses of water to make 'jewelry'.

markdown• 12 years ago

I did the same, but made lead sinkers for hand-line fishing.

wglb• 12 years ago

This is an excellent article, and shows why you need to do all the fussy finicky things that you need to.

It touches on two stories of personal interest to me. First, my maternal grandfather spent a fair amount of his time in a silver mine in the blacksmith shop. This was a small enough mine that mining was done with picks, shovels and the like. They would wear out, and need to go to the blacksmith shop to be refurbished. We had an old open coal forge that had been used by the previous owner sitting unused in one of our sheds. Grandpa came by one day to fix up one of his pickaxes. The forge had a blower powered by a hand crank. He first scooped the coal out from the hole in the middle of the bottom of the body of the forge. Then took a coffee can, placed it over the hole, and packed coal around the can, and sprayed water on it. He had me turn the crank as he lit the coal, gently at first, then stronger.

Once the heat was up, he began heating the tip of the axe. As he heated, he told stories of how you heat, then cool the tool. Too much heat could burn the tool. And when to take it out to shape the tool on the anvil. And how there was different types of quenching--water, oil. Depending on what the tool was to be used for.

The other story is that my brother (now retired) was a professional welder and instrument maker. He made instruments for telescopes. As a gift, he once gave me a pair of dice made of aluminum. Not particularly fancy, but he noted that the trick with aluminum is that it will suddenly melt on you without turning red.

WildUtah2• 12 years ago

without turning red.

Metal light emission depends almost entirely on blackbody radiation [0] which depends only on temperature. Aluminum melts at lower temperatures than iron and that's why iron glows before it melts and aluminum doesn't.

Blackbody radiation is also the principal source of sunlight (and all starlight). It was one of the first physical phenomena that required the quantum theory of energy to explain.

[0] http://en.wikipedia.org/wiki/Black-body_radiation

ericlippert8• 12 years ago

Indeed, though the iron crucible I use gets hot enough to be red hot. Whether the molten aluminum has a faint red glow about it or not I cannot say; I don't usually melt it at night.

schwarze_pest• 12 years ago

That reminds me of the legendary Nils Provos and his blacksmithing ambitions: http://www.wired.com/2013/02/provos/

His videos: https://www.youtube.com/user/mintwart

lukasm• 12 years ago

I used to play knights & merchant as a kid so I was able to understand it :)

Why aluminium? Low temp, high availability?

ericlippert8• 12 years ago

Exactly. It is extremely inexpensive -- the majority of the aluminum I melt I found abandoned on the side of the road -- it melts at only 1200 degrees F which is an easy charcoal fire. It is easy to machine, doesn't corrode, is hard enough to build interesting things, and lightweight.

clarry2• 12 years ago

Have you considered or tried melting steel though?

chiph• 12 years ago

Suggestion for next time - long sleeves. If a hot spatter lands on your arm, you could flinch and drop the crucible. And now you have a bigger problem.

Melting aluminum

Related Stories