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How to Cast Aluminum

By Contributing Writer ; Updated September 15, 2017

Casting aluminum is one of the least expensive ways to make metallic objects and with a little clean up work and polishing, the results are stunning and shine like the wings of the old WWII bombers. Cast aluminum melts at a hot but relatively low temperature and is easy to "carve" after you cast it.

Get a ceramic mini-crock pot liner. Take a heating element from a stove and stretch the coil so that it goes around the mini-crock pot at even intervals on the sides. The two ends of the coils should come out the side of the larger crock pot, where you will drill two holes that are 1/2-inch in diameter.

Attach two 1/2-inch diameter split bolt connectors to the heating element's ends. Later, when you insert this pot, the split connectors will stick out the sides from the holes.

Use a standard-sized round, ceramic crock-pot liner. Turn the pot over and place a 5-gallon bucket around it (both inverted). Cut the bottom off of the 5-gallon bucket. Place a standard empty Crisco can onto the center of the bottom of the larger crock pot to keep the mixture off this location. Fill the area between the larger pot and the plastic bucket with Perlite and chimney cement. The mixture should be 50% chimney cement and 50% perlite.

Mix the ingredients of the pot using a drill with a mixer attachment on it (usually used for mixing small batches of concrete) in a separate bucket and then pour it. Vibrate the sides of the mixture using a concrete vibrator to get out air bubbles. Bubbles make the cement crack under heat. Allow the cement mixture to harden 8-inches above the base of the larger pot.

Remove the 5-gallon bucket from the cement when cured. Remove the can from the underside of the cement. Don't worry if you have to destroy the can to get it out. Place a smaller pot inside the area where the can was located. Make sure that the split bolts stick out from the side of the smaller pot at the top.

Cut wires from inside an extension cord (on the "female" side of the cord) to hook up a light dimmer to the split bolts on heating element. Use the other end of the extension cord with the plug to plug into the wall.

Use the light dimmer to control the flow of electricity into the heating element. Use electrical tape and electrical shrink tubing to cover the wires where they are exposed. Use more of the chimney cement to insulate the wires on the slit bolts.

Drill two 1/2-inch diameter holes in either side of the smaller pot (under 1-inch of water to prevent shattering) 2-inches from the top. Put the bolts through the pot so that the threads stick out of the pot. Hand tighten the nuts and then weld them onto the bolts. These bolts will be used to handle the pot with a metal handle made from coat hanger wire.

Put the aluminum into the pot and turn up the power gradually until the aluminum starts to melt. Once you know the setting on the dimmer that the aluminum starts to melt at, mark this on the dimmer. Use a long metal ladle to scoop off the stuff that floats to the top when the aluminum is melted (called dross).

Pour the aluminum into the molds and allow the metal to cool.

Tip

Molds can be made of oily sand packed around Styrofoam. The foam catches fire and burns off with nasty fumes and a high flame (do this outside in a safe location). The metal replaces the foam and hardens to make the metal into the shape of the foam. Every mold needs two holes so that the metal can pour into one and hot gasses can escape out the other (especially as the foam melts).

Warning

Never cool the vessel quickly.

Never do this indoors or near trees, overhangs, gasoline, or anything else flammable.

Do not spill the aluminum since it is hot.

Test the device repeatedly by handling it as you will when it is hot before you ever turn the device on.

Use this device with extreme caution, treating the device as if it were to break or spill at any time.

Wear heat protective clothing and clothing that will shield you against splattering metal (like thick, layered leather).

Do not operate this device near water or wet surfaces.