After using charcoals for some time I started powering my furnace with propane gas. I started by constructing 2 burners and after a few uses I have to say its great regarding cleanliness and aluminum melting results. In this image I melted a bar of aluminum in just a few minutes and finished with many more ingots.
The down side of using propane is that it's more expensive then charcoals or waste oil.
The first propane burner I made following Ben Baker's design so many thanks to him for all his help and great sketchup design.
The first burner is constructed from a stainless steel pipe nipple 1/2"x8", bell reducer 1/2"x3/4", mig welding tip 0.6-0.023, mig welding adaptor-m6-mb36, square steel stock 3/8"x3/8" and washer 3/4" (air choke plate).
The second burner is constructed from a stainless steel pipe nipple 3/4"x6", T-joint 3/4", copper head plug 3/4", mig welding tip 0.6-0.023, mig welding adaptor-m6-mb36 and a washer 3/4" (air choke).
To create the adjustable choke I drilled a hole in the (3/4") side of the bell reducer and top of the 3/4" T-joint. Making the threaded hole with a tap and die bit.
I used a 6mm bit to drill the copper plug fitting in the mig tip adaptor.
I tried to take some images of the propane burner in action changing the ratio mix of the air and gas but in the images the only flame that could be seen is oxidizing blue flame. Oxidizing blue flame can destroy metal pipe crucibles very quickly leaving a nice hole and a pool of molten aluminum in the bottom of the foundry.
I haven't used an air blower combined with the propane burner before so I will try that in the future and post my experiment results. Once my foundry got to the right temperature I started pouring one crucible after the other for about 3 hours. The refractory insulation keeping all the heat inside the furnace is very important so it pays to make a good refractory.
Here is a video of my foundry in action using the propane burner before I installed the adjustable choke washer.................Next step a waste oil burner :-)
This is another addition to my furnace, I used a screw to secure the burner into the correct location and angle.