The beginnings of
a waste oil
Ronald E. Thompson
Copyright 2007, all rights reserved
Gun style burners look
complicated at first blush, but they are relatively simple when broken
down into the systems. A lot of the gear on one of these is for safety
in unattended operation and can be dispensed with,
greatly simplifying their use on a furnace.
A picture might help you visualize what I am trying to convey:
The gun burner consists of a blower, a fuel pump feeding fuel to a
nozzle at about 100 PSI, and a transformer that energizes a pair of
electrodes to ensure combustion with a large, nasty spark. The nozzle
and spark electrodes are contained in an air tube that directs the
blown air across the nozzle and the resultant fog of fuel, which is lit
by the constant spark, resulting in a very hot, white flame.
The whole thing can be run on a 120VAC extension cord.
So far I have learned that it is possible to burn alternate fuels in a
gun type burner intended to burn home heating oil (HHO). To burn
heavier fuels, such as waste vegetable oil (WVO) or waste motor oil
(WMO) you need to change to a siphon nozzle and heat the incoming fuel.
The siphon nozzle requires a small amount of compressed air to operate
and requires a filter, such as an automotive oil filter. The original
nozzles that come with these burners require a finer filter of 10
microns or better. It is possible to use the original nozzles for the
heavier fuels, but everyone who has reported trying it gave up due to
clogging problems causing too frequent disassembly, cleaning and/or
replacement of the nozzles.
The yahoo group (http://groups.yahoo.com/group/altfuelfurnace/)
has pictures and files showing several iterations
of homemade oil heaters. Most use band heaters or cartridge heaters and
a thermostat of some sort. The ideal temperature range is 150 to 160
degrees F. Any hotter, while improving the burn, will cause problems
with coking of the fuels and the resulting solids clogging the nozzle
The 'go to' source seems to be Patriot supply (http://www.patriot-supply.com/)
They have a search function on their site that is useful.
The siphon nozzles are about $20US and they require an adapter that is
about $17US (as of this writing, February, 2007).
As I said, they also require a small amount of compressed
air. Patriots web site has specs that show a need for around 5 PSI and
about 1 CFM of air flow (depending on the nozzle chosen).
Siphon nozzles can be had as low as .2 gallons per hour (GPH) up to 1
GPH, as shown on Patriots web site. Other sizes may be available from
I should also mention that gun burners are not the only game in town.
It is possible to atomize the oil in other ways than with a nozzle that
requires fine filtration.
I recently purchased a book from Colin Peck at http://www.artfulbodgermetalcasting.com/
It is a spring bound book that talks about building an oil fired
furnace. He uses a vacuum cleaner motor as his original blower, but ends up
making his own. He also made a coarse oil flow valve with no small
passages to clog easily. It is a workable design that accomplishes
quite a lot, but the book is pricey. Since it is from the UK, I had to
exchange US Dollars for Pounds and pay overseas shipping, all told
I also have an excellent book from Steve Chastain titled Build an Oil
Fired Tilting Furnace. It is available directly from Steve at http://stephenchastain.com/
Steve uses a large homemade blower and a venturi to atomize the oil.
Kind of like an over-sized carburetor for a lawn mower. Again there are
no small holes to clog. At half the price of the former book, Steve's
book is worth the price just for the burner info. Steve also has other
worthwhile books for sale on his site.
Both of these, however, are large furnaces, burning several gallons of
oil per hour. I am of the opinion that for a smaller furnace, the gun
burners offer more to the hobbyist. And if you are willing to buy the
fuel, they can run 'out of the box'. It is in trying to operate them on
free fuel that the mods are needed.
All of these are capable of iron melting temperatures, but in the case
of Steve's design, it it strictly for aluminum due to the built in