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Introduction to a Backyard Metal Foundry…
1. This article is for safe and mature people, because it's insanely dangerous. Your body is in danger, your eyes especially.
2. These are student notes, not professional advice. Do your own lengthy research. Don't take any risks.
3. Enjoy my notes and please let me know if you have tips and advice!
4. My first goal is to convert foam sculptures into aluminum metal.
5. This article is just a stub and shall be updated many times.
6. Molten-warm thanks to TheKingOfRandom on YouTube for his many experiments.
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Basic Melting Temperatures for Fairly Pure Metals…
* Pewter: 250 degree Celsius. Melts very easy. Can be melted with blow torch.
* Aluminum: 660 degrees Celsius.
* Brass: 900 to 950 degrees Celsius.
* Tin: 500 degrees F.
* Copper: About 1,984 degrees F. Same with gold and silver. Copper is heavy and looks good.
* Iron:
* Steel: Very high melting point.
* Titanium:
* Lead (toxic):
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Useful Tools…
Melting foundry with fuel. Scrap metal to melt into portable muffin-tin ingots. Crucible to hold molten metal. Metal cutting saw (tiny fine teeth). Thick and long gloves. Fine aquarium sand you can reuse many times. Chopped fire extinguisher as a crucible, or any pure steel crucible or official professional crucible.Tongs or a tool to pull your hot crucible out of the foundry.
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Random Tips…
* A “steel fire extinguisher” will attract a magnet, otherwise it's aluminum.
* Dropping molten metal on concrete is a danger because concrete has moisture bubbles which will explode.
* Melting scrap metal will often generate “slag” which is impurities in low-grade metal.
* Accidentally kneeling on molten metal, will instantly burn a hole in any fabric and your body.
* After dumping molten metal into a muffin ingot pan, tap the crucible on stone to clean it out.
* You can quickly convert Styrofoam sculptures into metal. The finer the sand, the higher the detail. Play Sand isn't very find, but some aquarium sand is excellent.
* Save good scrap metal and soda cans.
* Silica sand will melt, don't use it.
* Galvanised steel chain and some other metals put off a lethal fume, so first burn off the thin plating at a great distance where you can't smell it at all. It's preferred to never melt galvanized steel. Zinc when heated red hot, is exposed to oxides and becomes gaseous zinc oxide which can kill a human.
* Real hardwood charcoal get far hotter than briquettes.
* Soda cans aren't very pure, they produce a lot of “dross” or “slag” which means useless scum and mineral waste.
* Aluminum draws in a lot of gas, making your product a bit foam-like on the inside, so you can use flux and degassing additives to have a nice solid aluminum muffin. Cool the final cast slowly, to retain max strength.
* YouTube or Google about green sand casting using Styrofoam.
* The advantage to a “ground furnace” is the opening can be open or closed to keep the heat in. Where as a bucket furnace has a large opening letting a lot of the heat out even with the lid on.
* When melting aluminum, one spoonful of “Mortan lite salt” and “Arm & Hammer Super Washing Soda” aka Sodium Carbonate, wrapped in aluminum foil and into the crucible, will remove Hydrogen and thus eliminate your ugly pitting problem. This is not Baking Soda. Borax is another great flux chemical, useful for getting rid of impurities.
* When polishing sharp metal, it can fall and slice your leg open. Wear boots and long pants.
* Convert a Metal Foundry to GasBlaster Propane, by TheKingOfRandom on YouTube. Uses 8ft rubber hose, ball valve, couplings with Teflon tape, propane nozzle, wire feed welding contact tip, 4 socket cap screws, 6 inch steel pipe, reducer couplings, adjustable steel sheet as a regulator, washers, pressure gauge, regulator valve, flair fitting, presto-lite valve, and a few extra parts. The GasBlaster goes from 1psi to 50psi of propane. You can split your hose so there will be two GasBlastere torches, for a super fast heat. Video tutorial here: https://www.youtube.com/watch?v=eO8NwseRxSA
* * If heating your foundry quickly, the crucible could track from temperature differences, causing tension and warping in the metals.
* Dirt is an insulator, if you choose to bury your furnace in the ground, but it may take a long time to heat if the ground is frozen.
* Safety gear is vital at all times because materials weaken and break over time, causing spills and explosions. Wear long pants, long sleeves, steel toe boots, welding gloves, high-spectrum sunglasses, a thick leather hat, and be prepared for flying metal shrapnel and lethal spills. Multi-thousand-degree metal will pierce the body quickly. Stay upwind when around any smoke or fumes, as some smoke has toxins difficult to detect. An up-to-date certified fire extinguisher and garden hose shall be within reach at all times. Hair shall be tied back. Wear a face shield. Don't melt metal around trees, weeds, buildings, or anything flammable.
* Metals can be cut with a table saw and metal blade.
* Many metals will oxidize if you didn't pour in the right additives. Such as Borax being the most popular by far, and coal, salt, and other flux chemicals. I need to study the common flux chemicals.
* You may pour molten metal onto a wooden mold.
* Your propane burner won't likely work outside of the foundry, because it won't have a flame vortex (spinning flame) and will blow itself out.
* If metal has moisture in it, it will pop to evaporate, and cause sparks to shoot within a five foot area, so keep the foundry away from your house or anything that can possibly burn. If your crucible cracks and molten metal pours out onto concrete, there will also be a storm of popping fire as moisture in your concrete explodes. Crucibles only last so long, as they are heated and cooled a lot, so all of them eventually crack. Even steel factories have the rare disaster of 3,000 degree F metal spilling out into a room.
* Wear leather welding apron, a welding face mask, and leather gloves and boots.
* “Greensand” is a type of clay which looks like natural sand. When moist it holds its shape well, unless extreme heat flashes the moisture out of it. Talc baby powder prevents greensand from sticking to anything, so use a paintbrush to dust on the talc powder.
* You need a wide air gap around the crucible, for the fire vortex.
* Excess smoke can be controlled by adjusting your blower speed.
* Aluminum is easy to melt but difficult to weld, and very easy to cut and scratch, and won't rust. Steel melts much hotter, is harder to cut, but is very easy to weld, and will often rust.
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Internet Resources…
* DIY Trashcan Metal Foundry!: https://www.youtube.com/watch?v=y2RYYBRFu1A
* Tips for the DIY Trashcan Metal Foundry: https://www.youtube.com/watch?v=l2FuvKTyRMQ
* Convert a Metal Foundary to GasBlaster Propane, by TheKingOfRandom: https://www.youtube.com/watch?v=eO8NwseRxSA
* Instructables instructions on a cheap Mini Metal Foundry: http://www.instructables.com/id/How-To-Make-The-Mini-Metal-Foundry/
* Detailed DIY Metal Foundry instructions from FlamingFurnace Blog: http://www.flamingfurnace.com/2012/11/foundry-setup-crucible-flask-and.html
* LuckyGen1001 on YouTube, tutorial for Forced Air Propane Foundry: https://youtu.be/l697pB9X5TI
* Melting copper, which can be tricky: https://www.youtube.com/watch?v=JjZqEwiIEY0
* Melting metal with a giant magnifying glass: https://www.youtube.com/watch?v=8IdjbdLdXYo
* Mixing aluminum with brass in 2017: https://www.youtube.com/watch?v=_30lR-nbpXg
* Metal casting Play Sand in 2017: https://www.youtube.com/watch?v=xFq9wpF0L8M
* Make metal casting sandboxes in 2017: https://www.youtube.com/watch?v=RO3WnltsOx0
* Melting glass marbles with electricity: https://www.youtube.com/watch?v=1yf2uBiaOmU
* Tito4re on YouTube, melts metals into tools: https://www.youtube.com/user/21nal/videos
* MyFordBoy on YouTube shows how to cast a metal part using greensand: https://youtu.be/5GSHXC6fwq4
* MyFordBoy on YouTube shows advanced high-detail Greensand casting: https://youtu.be/M95bhPrDwA0
* MyFordBoy on YouTube shows examples of using his metal foundry: https://youtu.be/HJ9YoRMoO5Y
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