Waste Oil Burner





Introduction: Waste Oil Burner

I've been blacksmithing in my backyard on and off for a little over a year now. I've had no success with propane and charcoal doesn't really get hot enough. My forge itself is little more than a pile of bricks. After a while I decided I wanted to try casting aluminum and for that I needed more heat. Thus, I built my waste oil burner. This version of waste oil burner functions by vaporizing oil on contact with the hot steel. It's built primarily of plates of steel. it's a box shape because boxes are easier to weld. The only important thing is that there be some sort of chamber and a vent into which air might be blown. It doesn't have to be airtight or match specific dimensions. You could make it in a weekend if you were really driven. Quick, easy, but difficult to light. I've mostly provided pictures as written instructions aren't particularly helpful for this. Feel free to ask questions and/or post suggestions in the comments.

Step 1: Stuff

All right so this is what you need. Notice, the parts are fairly vague because I just made it with whatever I had laying around.

  • 1/4 inch steel (vents)
  • 1/2 inch steel (body)
  • 1/4 copper tubing
  • 1/4 inch needle valve (or something capable of regulating the oil flow)
  • Oil, and something in which to hold it
  • furnace blower, my design uses a blower with out dimensions of 3" by 2.5" but you could get by with anything from a vacuum cleaner to a squirrel cage blower if you had to, but of course the dimensions would have to be modified
  • Hose Clamps


  • Oxyacetylene Torch equipped to cut steel, or another form of gas powered cutting device
  • Angle Grinder, useful for touching up any mistakes and/or as an alternative to a torch (but that would take way longer)
  • Hacksaw, if you really feel the need to make this but don't have any of the above tools (about the equivalent of replacing an airplane engine with a hand crank)
  • Drill and Bits, 1/4 inch or whatever fits your oil line
  • Welder, arc, gas, whatever, take your pick (I used an arc welder)
  • Bench Grinder (when you realize that you suck at cutting steel and really have to clean up your cuts)
  • Burn Cream/Bandages (you'll thank me later)
  • Eye Protection, shades, safety glasses, welding mask, face protector
  • Screwdriver
  • Wrench
  • Whatever I Forgot to Mention Or You End Up Needing Anyway

Step 2: Cut the Steel

I've included the sketchup version of my design and the stl file version. It's too scale so it shouldn't be too hard to figure out. It's basically a box with some holes in it so it's about as simple as it gets. Its dimensions correspond with the size of my blower, you may have to change the dimensions too fit yours. Cut the steel apart. It doesn't have to be perfect but you can clean up the edges with whatever grinder you happen to have. Remember that the whole thing is probably going to be covered in oil or on fire at some point so accuracy and aesthetics don't matter much. At some point you'll probably think it's a good idea to pick up hot metal, don't. Admittedly, I could warn you all I wanted and you would still probably do it (I certainly did). Something about hot metal just begs to be picked up. Maybe it's the addled state I was in after inhaling burning metal and paint fumes but I just had to touch it. Anyway. Pyrophilia aside, melting through metal really is fun and fairly straightforward so I won't bother you with details much. Holes for the ducts will have to be cut at some point to so probably don't weld everything together before doing that.

Step 3: Weld

Fire up your welder and start sticking stuff together. I'd suggest putting the ducts together first so that you can fit them to the base and cut the holes for them. Tac the pieces together then weld a solid bead along every joint. Make sure your joints are solid because they're going to have to hold up to some fairly strong forces. It doesn't have to be airtight but any major gaps are going to let flame out. Follow the pictures (but don't look at them too closely, I'm a terrible welder). Weld the ducts first and then cut out the vent holes to fit them.

Step 4: FIRE IT UP! (and Last Details)

Drill the hole for the fuel line. This should be after the air gate but far enough from the fire that the tubing won't melt. Should be drilled in the air duct. You'll need an air gate unless you've got a rheostat attached to your blower. You'll also need to put a bend in a short piece of copper pipe attached to the needle valve. Start the fire by stuffing the blower full of newspaper or oil soaked rags. Start with low air and no oil. Once the burner gets hot start adding oil and air. This isn't easy to get right and is mostly trial and error.

Step 5: Air Gate

Most blowers even remotely suited to running forges/foundries are air cooled or have to be run at full power for electrical reasons. This basically means that you can't just connect a rheostat or stick something over the blower opening to restrict the airflow. This leaves us with the need to cover the fan output somehow in an adjustable way. This isn't too hard to make. Just cut a slot in either side of the vent and cut a bar of metal to slide across the opening. Notch one end so that you can adjust the airflow to some extent. this can be done with a torch but you will need to grind the edges or the gate will never slide. You really have to do this after you have made the vent because you never know how the vent will turn out. Mine was off by almost a quarter inch but it still works fine. The important thing is to not expect the gate to fit if you cut it out before assembling the vent.



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I've been wanting to make a waste oil burner. How much oil do you use per hour? A pint? Quart? Gallon? Does the burner get red hot, or does the air flow keep the temperature down?

The real trick with melting is to have a container (the furnace) with a hot face, and insulation.

I currently use a propane burner and can blacksmith and melt copper with it. The trick is having an air tight forge body. If you got enough bricks and then plastered the interior with a high temp furnace cement.

It looks like you're using high density fire bricks which are a great hot face but don't give much insulation value. Having a durable hot face is great but I can't stress the value of insulation enough. I struggled for a long time with insufficient insulation and when I finally built a furnace with enough, things became much easier.

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Thanks for the suggestion. I think I went through half a gallon or so in about two hours, but I'm still working on getting everything right. I have near zero experience using any kind of insulation but I definitely agree. My burner takes forever to get up to oil vaporizing temperatures and the foundry itself lets out so much heat that even with a massive oil flame aluminum still takes a while to melt. I'm thinking refractory and ceramic blanket should solve the problem but I'm not sure.

Blankets work well for insulation. A single layer will work, but more is always going to be better. You can get high temp furnace cement at most big box stores, smear it over the inside face of the ceramic blanket and that will give you a hot face. It's important for reflecting infrared back into the melt.

You could use your high density bricks for a face and then use low density bricks around them. Low density bricks are relatively cheap. They won't hold up as a hot face for very long though.

I've been using a moldable refractory for my hot face and then mixing that refractory with shredded styrofoam. The foam burns away but the air pockets remain and serve as insulation.

Just for an idea of size, my metal furnace is a 2 ft tall metal garbage can that I put forms in and filled with refractory. My forge is an old mailbox that I cut a hole in the side of for the burner and again filled with refractory.

Big box store employee here. We can't get high temp cement or fire brick from Quikrete or Ash Grove, however each store is different. Might be better to try a store that specializes in fireplaces, hearths and in ground fire pits.

That's just the information I needed. One question though, what do you mean by hot face?

It's the surface that comes in direct contact with your heated gas. The hot face of the furnace. In general the hot face is a material that does two things. 1 Reflect infrared light back into a melt. 2 Protects the insulation layer from extreme temperatures.

Insulation, especially ceramic blankets and soft fire brick can break down in very high temperatures. If they're protected by a layer of material that can take the heat, they last much longer. These high temperature materials tend to be dense and not very good at being an insulator. Thus the need for the interior material that handles the heat (the hot face) and a lighter material that holds in the heat. They're usually rated for 5000 degree F temps while insulation material is rated for somewhere around 2500. You're probably capable of hitting low to mid 3000's with a waste oil burner if my memory serves. It would therefore break down the lower temperature rated material without something to protect it.

Very informative. Sounds like I'm going to have to start work on version 2...

Depending on the source of the oil and the combustion conditions, the emissions could present a health hazard to yourself or an environmental hazard out of compliance with various regulations. I know that a small backyard forge seems like a minor thing, but for yourself, being very close to the operation, chronic exposure even to very low concentrations of some emissions can have long-term consequences. And on a broader scale, these kinds of operations can have a surprising impact. I don't remember the exact numbers, but I recall data showing that operating a typical 2-stoke lawnmower for an hour resulted in more emissions than driving a modern, properly-maintained car for HUNDREDS of miles. Please be careful to take care of yourself and of the air that the rest of us breathe.

Dude_NZ, I sand polystyrene to make RC Planes and the natives around here tell the cops Im making NAPALM, I wouldnt suggest you make a pipe bomb or anything. Thats a joke, my relaitive hostorically form 'Rangiora' have gone fissing and come back with rabbits, gone shooting and come back with trout, made pipe boms up the ashley and none of them were capable of dring the car to the emergency after it went off... NZers are 'effing inbreed.

1 reply

'O' is for Orsome..... Fissing is for Fusion and im moving to RUSSIA. LOL. Dont blow your self up.

Hi, Nice work.

A few tips. You will get better performance (more heat and a cleaner burn) if you put the output of this burner into another chamber. Several people use a refractory lined old propane or compressor cylinder. Ideal would be ceramic blanket lined with a hard refractory face over it. Also insulating your burner in this setup will get you more heat as you will be losing a lot of radiated heat from the hot 'fire box'.

I have experimented with similar burners for my foundry furnace.

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I'm looking into finding some refractory (hard to get the components at a decent price where I live) because I'd like to build a chamber like you described. For now, bricks will have to do. Anyway, my burner takes forever to get up to heat, do you think wrapping it in ceramic blanket would help?

Ceramic blanket will help. Heat radiated off your 'fire box' is heat that cant be used for your forging.

As refractory you do have some options including some homebrew mixtures. They might not be the best but if you are on a budget or cant get the materials they can be better than nothing. Your work chamber lined with a layer of ceramic blanket, then another layer imprgnated in a mix of kaolin clay and silica or alumina (applyed in a slurry) may work well and can be bought from ceramics suppliers.

If you can build a venturi burner that atomises the oil into a fine mist you might not need a preheat chamber then all the energy is available for your forging.

There are lots of plans for venturi nozzles that do not require delevan or hago nozzles and can be built with parts from a hardware store.

This might have already been answered but where did you buy the furnace blower from?

2 replies

Garage sale. Looks like ebay cells them for around $20 but I'm sure you could find something cheaper with a bit of effort. If you can't get a metal blower you can always just attach a longer pipe and use something like a vacuum cleaner (I used a shopvac for a while) or a hairdryer. I paid 5 bucks for mine so definitely hit garage sales. Seems like the kind of thing that people just have laying around and will sell you for next to nothing. Good Luck

ok thanks, I will keep an eye out

Hey Slime Eel

Good job! In the oil fields we had an oil(diesel) heater in the doghouse(changing shack) and the line came into the fire box horizontally across the chamber then u shaped back to center to the drip point. I think it was to heat the oil a bit while still in the pipe. It had an elevated splash plate(put a bit of oil soaked paper under the splashplate to start). Just some ideas to kick around for your next one.. Gives me ideas for a future forge!!

3 replies

Thank You! I was considering a splash plate type design but I wasn't sure how it would hold up, sounds promising from your comment. The oil heating thing I will have to try as well. I'm having some trouble getting enough oil into the forge but some heat should lower the viscosity and help it flow.

Slime Eel

Try a quart of diesel per 6 quarts of waste oil. That will thin it down a fair amount. The heater was 18/24 inch pipe vertical design. Kind of like a stretched franklin or vertical barrel stove.. So we had lots of room for the splash plate.. during the time I was in the oil fields I never saw a splash plate failure or issue. One person got the heater pretty hot by leaving the valve open too far. Once the heating pipe is hot you will be able to slow down the flow.. It helps atomize and thin the fuel.. Cheers Herdin