Introduction: Build a Foundry and Sand-cast Aluminum.
Second Prize in the
Hello instructableers, DIYers, and Internet people everywhere! Welcome to my debut instructable!!!!
(Whooo, We love you Fenris! You rock! Give me your socks for my creepily obsessive collection of things related to you!).
Thank you, thank you! But really, I must get to the instructable, settle down please.
In this instructable, I will detail how to construct a simple, cheap, and effective foundry, capable of melting aluminum. This foundry can be built quickly, with little tools or money, and is great for beginning metal-casters.
I'm entering this in the Epilog laser cutter challenge, so if you like it (as if you couldn't), please vote.
I'll be your best friend ;)
Step 1: How This Is Green
Before I instructify your minds, let me tell you how this project is green.
I live in Hattiesburg, Mississippi, and in Hattiesburg there is no recycling center. The nearest center is in Jackson, Mississippi; which is about 80 miles away. Nobody wants to drive 2 hours just to turn in some cans they could have thrown away in 5 seconds.
That's where me and my friends come in.
Our friends, family, and even random people who just want to recycle bring us pounds of aluminum cans each week, which ordinarily would just be taking up space in a landfill.
We melt down their trash to create tools or art, which we then can either sell or give away.
And though this foundry design pollutes the air with smoke and fumes, it teaches us (and any other beginning metal-caster who wishes to learn with us) what we need to know to build greener, more efficient designs which run off of clean-burning propane or use waste-oil as the fuel (reducing the amount of toxic chemicals people would be dumping elsewhere).
As we learn how to build cleaner, more efficient foundries, I will post instructables, so people in places like Hattiesburg, MS, will be able to do their part to save our planet.
On to the legalities!
Step 2: Legal and Precautionary Statements.
First off, this instructable deals with fire, molten metal, sharp edges, electrical equipment near water, burning paint/other noxious fumes, and probably some other dangers I don't even know about. If you are a clutzy, hyper, or unattentive person you really shouldn't try doing this.
By reading this instructable you agree that I am not liable for any of the numerous injuries you may incur, property damaged, people harmed, or anything else you could think to sue me over, while building and operating the foundry described within said instructable
That being said, If you follow my instructions you should have no problems with safety. I will do my best to detail the safest way to do this.
Step 3: Read Up. Arm Yourself With Knowledge
Casting metals can be complicated. It's a good idea to get a feel for it first.
Some good examples of what we're doing.
A list of even MORE links.
Step 4: Materials and Tools.
Required to build furnace
- Drill with large bit suitable for steel. (Hammer and large steel spike can be substituted)
- Tin snips
- 2 coffee cans of equal dimensions (one for furnace, one for air chamber)
- 1 hair dryer with a cold air setting
- 1 tin can (Blue Runner bean cans are the perfect size and are very strurdy)
- At least 4 metal stakes (optional)
- Instant light charcoal
- Charcoal lighter fluid
- Barbeque lighter (the long-nozzled kind)
- A bucket of water (to cool hot tools)
- Aluminum cans
- 3 or more boxes (optional)
- Tongs (I use 2 pairs)
- Some sort of long, metal stick
- Leather gloves (preferably welding)
- 100% Leather and/or cotton upper torso/arm coverings (Big Smith jackets are perfect)
- Gas mask (optional, you can just hold your breath when near the furnace)
- a large container
- Something to impint a design in sand with or way to draw in sand (pottery, carvings, body parts
Step 5: Building the Air Chamber
Use your tin snips to cut a hole in one of the coffee cans for the hairdryer to fit into. It's O.K. if there are some corners that don't quite conform to the hair-dryers nozzle, mine don't and my foundry works just fine (See pic 2)
Step 6: Building the Fire Chamber
Using your drill (or hammer/spike combo) make holes in the bottom of the other coffee can. Again uniformity is not a requirement.
Step 7: Assembling the Furnace
There is a simple way to do this-
1. Insert hair-dryer into air chamber
2. Put fire chamber on top of air chamber
-Which is easy as pie but extremely dangerous. If the fire chamber is nudged even the slightest bit the whole thing will topple over, creating a gauntlet of hot coals and molten metal at your feet.
On the other hand though, being able to remove the fire chamber from the furnace gives you the advantage of being able to shake out the coal dust that will eventually clog the holes to the air chamber. This allows you to keep the fire burning hot longer for multiple melts.
If you feel you can't handle having the fire chamber loose, than you should dig a fire pit, fill it with sand, and put metal stakes in the ground running along the sides of the cans. This will hold the cans in place but still allow you to quickly remove the fire chamber.
Step 8: Destroying Your Aluminum Cans.
It is important to seperate the parts of the can, as they all produce different amounts of dross (trash in the metal which has to be removed), and should be melted at different points in each smelting.
The 3 sections which have to be seperated are the top, the sides, and the bottom of the can.
My favorite method for destroying the cans is illustrated in the pictures. Unfortunately, I can't get the image notes to work, so you'll have to read the procedure up here and follow along with the pictures below.
1. Cut or rip the can in half.
2. Make a slit in the top half, perpindicular to the lid.
3. Tear along the slit and pull the siding off of the can top.
4. Make a slit in the bottom half of the can, at an angle to the bottom.
5. Tear as close to the bottom as you can, and remove siding.
This goes much faster if you form a production line with some friends in which one person has one of the steps above assigned to him/her.
I sort the cans into boxes of halves, siding, tops, and bottoms, with the occasional box for cans with painted tops or bottoms.
Once you're done with your cans, it's time to ready your foundry.
Step 9: Laying the Coal.
With the furnace assembled, place a ring of coals around the bottom of the fire chamber (pic 1), Then place two coals perpendicular to the ground in the center of the ring, leaning against each other (pics 2+3). This increases airflow under the can, which helps to heat all the coals and ultimately provides a better melt. The wrong way to do this would be to put one coal flat under the can, (pic 4) blocking airflow from the center of the furnace.
Next put the tin (steel actually) can on top of the two central coals and add coals evenly to the sides of the tin untill it stands on it's own.
Step 10: Making the Mold
If you don't want to make a mold, just some metal blobs (ingots), you can pour the molten aluminum into a muffin tin. The ingots can be re-melted later if you need the metal.
Making a sand mold is easy. All you need is some sand and a way to imprint a design in it.
You could do this with a stick or something, but it probably wouldn't turn out well. I find you get the best results when you use something with a 3-D pattern on it. In this instance I used some pottery, I found at the flea market.
If you have a friend (or friends) working with you, they could make a cool design, while you melt the metal.
Now all that's left to do is prepare your work-space.
Step 11: Foundry Feng-shui.
There are a million possible misfortunes waiting in a foundry, and you can eliminate almost all of them by being prepared.
I have here some pictures of my foundry set-up and running, as well as some pictures of me operating it.
Notice that the cords are held away from the walkspace with a bucket so I won't trip on them, and that the water and aluminum (i.e. conductive materials) are on the other side of the walkspace.
You need to be able to walk in a complete circle around the furnace without bumping into anything.
The water and mold need to be where you can reach them quickly when you need them, but not so close to you that you bump them.
If you've done all of the above, it's finally time to start up you're furnace!
Step 12: Starting the Furnace. (FINALLY!)
Make sure all your safety gear is in place and then get ready to finally do some metal-melting!
First load your crucible half-way full of can tops, they burn the cleanest, so burning them first yields more molten aluminum to submerge other can parts in.
Then, light the charcoal!!! Whoooo! fire!
If you use regular charcoal, you have to use lighter fluid, which can drip through the furnace onto the hairdryer, for this reason I only use coals that light instantly in my furnace.
As soon as you think all the coals under and around the crucible are lit, start the hair-dryer.
Next you need to add coals to the side of the crucible untill they form as even a layer as possible around it's center.
Once the can tops start to melt and you can see the can glowing red it's time to move on to the next step.
Step 13: Operating the Furnace.
I had several instructional videos to show you, but my mother managed to unintentionally delete them off of her camera.
The world weeps.
It's O.K. though, operating the furnace is pretty straight-forward.
All you really need to do is
1.Fill the crucible of aluminum scraps
2.Cool the tongs in water
3.Let the aluminum melt
4.Use a metal pole to remove dross (Gross stuff floating at the surface)
5.Cool metal pole in water.
If you don't have a gas-mask then you need to hold your breath when you feel hot air from the furnace hitting your face
Aluminum scraps should be melted in this order; can tops, can bottoms, and then can sides.
This is in order of metal-to-dross yield.
Dross should be removed quickly after the aluminum melts, or else it will clump together with some of the aluminum and stick to the sides of the can, reducing the amount of pure aluminum you can get per pour. There are some pictures of me removing dross below.
Also you must be careful with hot tools, not only because they can burn you, but because they can burn other things.
For example, If you use hot tongs to try to grab coal out of the coal-bag, the coal could ignite setting the entire bag aflame.
When you notice that the crucible's glow is starting to fade, either add more coal to the fire, or prepare your mold for pouring.
Step 14: Pouring the Mold
The most self-explanatory step. Pick up your crucible with your tongs and pour the molten aluminum into your mold.
The aluminum has a smooth look to it's surface while it's still molten, but if you watch closely, you can see it start to crystallize.
Try not to pour from too high or the aluminum will crush the detail out of the mold.
Again, I apologize for the lack of videos, I'll try to upload some soon.
Here's a pic of the finished product. (I didn't use enough aluminum) :(
Step 15: Come On...
...lets be honest with ourselves, you know you loved this instructable, I know you loved this instructable, we both know you loved this instructable. So why are we playing this game? Stop playing coy and vote for this instructable!
Seriously though, the laser cutter would be put to good use.
We have a be nice policy.
Please be positive and constructive.