One of the easiest gadgets I've made.  Made it out of a 100gallon pressure tank.  You can get these for free if you look around...once the diaphram burst they're worthless.  Simply cut it down to a usable height, cut a hatch in it (which I had to square off) build a little pedestal inside for my hot plate, cut the old top off the disgarded end and welded it down and cut a chimney for it.  Tada...

http://www.performancescene.net/forum/attachment.php?attachmentid=34&d=1135333549

It burns waste oil.  Right now it's not plumbed up, but I'll weld a little resavoir to the side of it to store about 2~3 gallons of oil.  It'll serve as a heater for the oil, that way.  It'll then drip onto the plate inside via copper tubing and some kind of pinch metering device.  I "may" have to build a seperate resavoire for better metering, then it'll have copper tubing fuel it and the tubing will wrap around the exhaust a few times to heat the oil.

I've ran it straight open like this for an hour or so without disapointment.  I place about half a cup of waste oil (I have a 55 gallon drum of it, plus some) on the crushed cinders (volcanic rock) and a little gasoline to get it started.  Waste oil has to be hot before it will burn.  After I got it going really well I've been tossing a half cup in every once in a while.  At the rate it's goin, burning with unmetered air, it's going through about 3/4~1 quart of waste oil every hour and producing lots of heat.

Best thing?  Uses old oil and burns it cleanly.  It'll burn waste oil, fuel oil, gear oil, old grease, cooking oil, anything corn based, fuel oil (kerosine, lamp oil, etc...much more efficient but more expensive) and a sleugh of other worthless crap.  At a total of $.33 (starter gasoline), it's one of the best investments I've made.

i'll have to keep that in mind when i get a garage of my own, i have a 55 gal drum about half full of various types of used oils at my parents house.

Do so...it's cheap and, despite what anyone would tell you, it burns cleanly off heated oils.

Tonight I'll ge tthis things fuel line plumbed in and chimney it up in my shop.

Second best thing?  Works as a great incenerator, too.

third best thing? finally an easy way to destroy all that junk mail that comes with your name/address printed on them (you know. ccard offers, blah blah)

i don't have a garage  :x