Building a waste oil burning stove for my shop

[LetsRoll]

I'm in the process of building a waste oil burning stove for my shop. I got the idea from a web page I was reading at mother earth news Roger Sanders' Waste Oil Heater. Then some folks took the stove to the next level. So, I decided I was tired of wasting money on buying LP for the radiant heater. It does just fine heating my shop. But the price of LP is killing my wallet. I have a 1000 gallon tank that I use for the house and my shop. Three forms of heaters draw from this tank (house heater, gas logs and the heater in my shop). As soon as I get this heater done and up and running. I'll be taking the radiant heater down and selling it. Ok, on to the heater. Since my radiant heater heated rather well. I decided to take that route. What I've done is, cut a 6 foot long, 24 inch from side to side, 3/8 inch thick natural gas pipe in half and welded them together. Between the two, I welded two 6 inch pipes for the exhaust to pass into the top stove pipe. So far, what you see in the pictures is as far as I've got. I would have gotten further on the project, but I ran into vehicle problems on Friday on my way to get some fuel for the torch. So, I spent Saturday fixing my truck. I got the truck fixed and today I went and got the exhaust pipe that you see in the picture on my trailor. I need to finish welding the grate brackets in and weld the grate supports to the grate itself. Then weld the ends on the top and bottom of both pipes. Finish it off by building the door and cut a hole in the top of it and then start on the exhaust pipe. I still need to machine a piece for the oil burner. I'm not sure if I'm going to add a intake pipe or not. I already have a damper, just need to add it to the exhaust pipe. Even thou I will be burning waste oil. I'm still setting it up for firewood incase I'm not happy with the waste oil performance. So far money wise, the six foot natural gas pipe cost me $30, the metal for the ends and for the door cost me $170 and the 8 inch, 35 foot long exhaust pipe cost me $50. The two six inch pipe that is welded between the two big pipes, I got that from my father-n-law for free. The legs where cut from an old welding table I had. The grate was free from a friend from work . I just have to cut him a small piece for his camping stove. You can see how much of the grate I have left over in the one picture. The angle iron for the grate to lay on, I got that from my steel scrap pile. I already had the damper. $250 dollars so far in material. Now for welding gas (shielding gas) and acetylene and oxygen for the torch. All of my 80 pound tanks for my torch and welder, I own them, there not rented. 80 pounds is the biggest they will sell. Anything bigger, you can only rent them. One bottle for the welder $50, one bottle of acetylene $65 and one bottle of oxygen $50. Total for welding and cutting was $165. So far, I have $415 tide up in this project. I'm trying to keep it at $500 or under. I still need to build the hood for the exhaust pipe, but I have a 4x4 piece of sheet metal that I will be using for that. I dont think I will have to buy anything else. I might have to fill the bottle for the welder one more time.

~Edit~ The compressor tank will be my waste oil tank. The motor for the compressor is junk.

 

[Tig]

A mechanic friend of mine had a stove that looked like that. He would let his firewood soak in a pail of used oil before it went in the stove.
I'm interested in knowing how much heat you get out of a gallon of used oil.
I'd like to build a mini oil burner for my ice fishing shack.

 

[Tom_Veatch]

...I'm interested in knowing how much heat you get out of a gallon of used oil....

As I recall, petroleum fuels yield about 16-18,000 BTU/LB depending on the particular fuel. Useable heat? Depends on how much goes up the flue, but you ought to be able to realize half or more depending on the particular design of the burner/heat exchanger.

 

[LetsRoll]

A mechanic friend of mine had a stove that looked like that. He would let his firewood soak in a pail of used oil before it went in the stove.
I'm interested in knowing how much heat you get out of a gallon of used oil.
I'd like to build a mini oil burner for my ice fishing shack.

The key to these men stoves is controlling the oil. And Roger from the link that I provided, was able to control his with the conical oil burner, intake pipe and the oil flow control valve. The oil pool diameter and the right amount of air is vital for a effective and essential control burn of waste oil. I've seen several stoves and have heard about not being able to control the amount of heat(low burn). Roger has been able to control all the problems that was plagued with most heaters. For me, I've seen the setup that I'm building in action using firewood and they put out a ton of heat. Right now, a friend of mine has one that he uses to heat his 60x80 shop and it has a 14 foot ceiling (he's using firewood). My shop is only 30x40 with 10 foot ceiling that does not have the ceiling in it. The 10 foot is from the concrete to the bottom of the rafters. My friend has a ceiling in his shop. It only takes about 30 minutes to bring his heat up to about 75 to 80 degrees. My shop is insulated, so I should be able to bring the heat up pretty quick. What I like is being able to control the heat. And also have a clean burn and efficient burn. I want to use waste oil cause I will have no money in waste oil. Even firewood cost money. The first year I use mine will pay off every dime I have spent to build mine.

 

[LetsRoll]

As I recall, petroleum fuels yield about 16-18,000 BTU/LB depending on the particular fuel. Useable heat? Depends on how much goes up the flue, but you ought to be able to realize half or more depending on the particular design of the burner/heat exchanger.

Useable heat?, then what is the reason for building this stove for burning waste oil. I have no clue what your driving at. ???~16-18,000 BTU~???, my radiant heater put out more than that.

 

[wmgeorge]

You are going to have a lot of waste heat up at the high ceiling, invest in a couple of inexpensive paddle fans. In fact I had a couple to give away a while back...

When you are venting this oil / wood burner outside you must use triple wall pipe or other venting approved for the 1,000 degree plus stack temperature. This type of Class A venting also as I recall must have at least 2" of clearance to any combustible material. The Code requires 18 inches for clearance around single wall pipe, which I think needs to be at least 24 gauge non galvanized.
DO NOT use "B" double wall vent pipe that was used on a gas furnace! It is only rated for 500 degrees or so.

I've never built a waste oil burner with gravity feed like I think you are designing, but the commercial ones I've worked on used a oil pump and compressed air to atomize the oil and then lite it off with a spark. The problems we had with those was the oil had dirt, metal and other particles that clogged up the filter pretty often. Or they had anti-freeze, kerosene and sometimes other flammable liquids in the waste oil that made them somewhat exciting to be around!

The Mother Earth News also had some follow up articles on that waste oil design. Good luck and be safe!!

 

[wmgeorge]

Useable heat?, then what is the reason for building this stove for burning waste oil. I have no clue what your driving at. ???~16-18,000 BTU~???, my radiant heater put out more than that.

He was saying oil by the Lb BTU's. Waste oil will have about 140,000 BTU's per gallon input to the burner. What you get out in BTU's depends on how efficient the burner is... I have no idea how these homemade gravity burners do, but the commercial atomizing oil burners run 80%, to 94%.

 

[RonMar]

He was saying oil by the Lb BTU's. Waste oil will have about 140,000 BTU's per gallon input to the burner. What you get out in BTU's depends on how efficient the burner is... I have no idea how these homemade gravity burners do, but the commercial atomizing oil burners run 80%, to 94%.

Yep, a couple of efficiencies involved here. First you are converting liquid fuel to hot gas. Then you are converting hot gas into warm, safe to breathe room air. Every conversion has loss. the effectiveness of the first conversion is the burner efficiency as mentioned. The second conversion is dependent on heat exchange efficiency IE: How much heat gets into the space vis how much goes up the exhaust to the outside...

Say you burn that 140,000 BTU gallon over an hour at 80% efficiency. That means you are only creating 112,000 BTU of available heat from that fuel. the rest is going up the pipe as unburnt vapors that still have some convertable energy in them. Now if your heat exchange efficiency is only say 75%, then that 112,000 BTU is only transfering 84,000BTU into the space over the course of an hour...

Barrel stoves seem to be pretty efficient, probably due to their large surface area and the slower flow thru the larger chambers gives ample time to transfer heat. The problem you may wind up with is the formation of hard carbon from the oil burn. The combustion has to be very very hot and very complete or you will build up carbon which will condense on the inside skin which will insulate it from the inside and lower the exchange efficiency. the ammount of carbon buildup you experience will be directly related to how efficient your burner is at breaking down the fuel. I would leave that upper chamber with a way of access to allow cleaning...

Something as simple as a vapor barrier tacked across your rafters to separate the work space with the area up among the trusses would greatly reduce the ammount of area you are trying to heat. You will of course still transfer heat thru the vapor barrier, but it will be at a reduced rate.

 

[6sunset6]

I looked at waste oil one time. You need a lot of oil , Kind of the same amount as if you were heating your house, Less for say 60d and less if it's only weekends but still a lot of oil. A friend of mine owned a gas station, did oil changes and did not have enough for the season.
I use a double drum like that SS drums kit from NH and burn wood. 14' high 32' x 64' Need a ceiling fan to drive the heat lower than 6 ' off the floor. Should have put radient heat pipes in the floor and used antifreeze in a wood fired boiler. Ther is 2" of foam under the concrete , does matter still cold. Other thing I should have done is heat my tool box. Cold tools are hard to use.

 

[Bill Barrett]

I wanted to play with that style burner for some time. For now I would plan on this as supplimental heat, at least get the bugs out and see how much oil you will need. Don't sell your nice radiant heater too soon! Are you going to make access panels to clean the top barrel?