Picture of Waste Oil Forge

This instructable will take you through he steps necessary to constructing a waste oil forge and lighting it. The forge takes in oil, atomizes it, and injects it into a combustion chamber along with a steady stream of air (provided by an electric leaf blower in my case). The oil will vaporize in the combustion chamber and ignite generating enough heat to melt aluminum, brass, iron, and potentially hot enough to fuse low-temp ceramics. The beauty of this machine is it’s almost as cheap to build as it is to run. I was able to construct mine out of some scrap metal and about 30 dollars worth of hardware supplies, no welding required! Additionally this forge should be able to accept a wide range of fuels, I primarily ran mine off of used fryer oil I collected from the bins behind restaurants, but I’ve found that this thing will readily burn; used motor oil, hydraulic oil, melted candle wax, even warm bacon grease. While some fuels work a little better than others, as long as it’s a liquid hydrocarbon this forge will eat it and give you tons of heat.

 WARNING: This beast is dangerous! Your dealing with hot oil and temperatures exceeding 2700 degrees Fahrenheit, so, do it outdoors away from structures and anything flammable. Never leave this thing running unattended even for a minute, don’t even turn your back on it. Keep in mind, WATER MAKES OIL FIRES WORSE! Way worse, so have a fire extinguisher ready. Wear dense clothing you can take off quickly.  And lastly, keep your distance when your not working with it, of course you’ll have to mess with it some while its running, but limit your time around it and you’ll limit your chances of getting a burn. 

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Jim L.1 year ago

I made a similar forge. I used lava.rock (from a gas grill) as my thermal mass/burner/wick. The whole thing kinda looked like a boot with the toe cut off.

When I got it up to temp I would put a lid on it (also made from refrac ) that included the drip fuel feed.

Temps produced would get steel up to nonmagnetic in about a minute. It would also have a tendency to melt the lava rock.

Air was injected through the side at an angle to induce a vortex internally. The "over pressure" would exit the forge through the "open toe" portion as a two foot flame.

It smoked like the gates of hell until operating temps were achieved. Big problem happened when I neglected to repair the refrac inside the combustion chamber.

No fire, but the thing started to hemorrhage fuel through the resulting cracks that came from over temp.

Your design looks more efficient. How is it with over heating?

This forge appears to be very dangerous so why build it. I think the only reason to build such a forge is because you have gallons of waste oil and need to dispose of it. Additionally, since it seems to limited in the metal it can melt or heat to a workable heat, why take the risks mentioned, unless you need to do high risk things for entertainment. Also, this forge is very complicated to build and there are many other types of forges that are easier to build and much safer to operate.

With all due respect, I entirely disagree. To be honest, it's hardly any more dangerous than a gas-operated forge or any forge that can get to 2700+ temp range. This is mostly because the danger of such a thing comes with the nature of forging and metallurgy. And I'd say the temperature range alone makes it very well suited for a variety of materials; he only chooses to refine Al ingots, not he can only melt Al. All things considered, I'd say this is a very thrifty, highly versatile forge! I'd like to make one if only I had the time :)

jdaley997023 years ago
Wow I suppose I may have a use for the 55 gallon drum of used race car oil now! Thanks
i like your oil forg