It's basically just a nozzle with an oil line and an air line attached, the oil tank is pressurized to force the oil to the nozzle.
It seems to runs best when the tank pressure is set to 20 psi (regardless of how open the air line is). The pictures below show it running on something like 20 weight but I've got a lot of 50w oil with some sort of additive that makes it even thicker (I got the oil from some amateur racers). The 50w seems to be too thick so I mix it half and half with the 20 (I'm not really sure that the oil is actually mixing or if it separates once it sits for long enough), on top of that I have to run my air line at full bore. With all of the extra oxygen, the sludgy mixture seems to burn without any smoke and the flame actually has some purple flares at the base.
The polyethylene tubing is the air line, the vinyl is for the oil input, and the male quick connect was supposed to be for a propane inlet to warm up/start the burner on but I've kind of ditched it, now I just start a small wood fire under the burner to get it going. The copper winding around the base are for preheating the oil (not sure how well it actually works though). The holes were meant to provide more oxygen to the propane nozzle through a slight abusing of the venturi effect but they work pretty well at supplying extra air to the oil stream too.
The picture's old but there's the air tank (red) and oil reservoir (PVC).
And, of course, testing the burner
Some pictures of my super makeshift foundry and the burner in action (with heavier oils) to come
