These pictures were submitted by Peter Grant (email@example.com) and are of his furnace and oil burner.
I have seen all sorts of buckets and propane tank furnaces, and not having any of those on hand I found a good replacement. My brother in law gave me a smoker grill about three years ago for my birthday, and I never could get the damn thing to work right. So it sat under a pile of stuff in the breezeway to the carport just waiting for its big moment. It has about three or so inches of portland cement based refractory mix in it and the internal bore measures around ten inches wide. Someday I will get ambitious and get some real castable refractory to replace it with but this will work just fine for now. I put a thin hot face of furnace cement mixed with sand to help protect the lining but it is already flaking off. The lid has no reinforcement in it, the domed shape and a raised ring (originally to keep the top from sliding too far in) will hold the concrete mix in just fine. I think it actually works pretty well as an insulator, because the outside takes quite a while to heat up. I used some vermiculite that I found in my old garage . I used perlite in the burner, but I ran out and perlite is hard to find out of season.
Burning out the refractory.
I have done a couple of melts so far, with good results. An old lawnmower engine and about twenty feet of aluminum power cable have bitten the dust and are now ingots. I am in the process of making a ball mill/screener/muller contraption so I haven't mixed up any greensand yet. I am looking forward to doing my first casting. I have ordered the Gingery book set and am planning to cast and build myself a lathe.
I decided to go with a WMO burner, because (a) it's fairly easy to construct, (b) I already have about 50 gallons of oil just sitting around, and (c) it could potentially melt iron when I get it running better. This is a modified (who doesn't modify it?) Ursutz style burner. This is the Mk.I version. I have since already progressed to the Mk.II mods and am currently in the planning stages of the Mk.III revision. I don't have pics of these, however, and the Mk.II is pretty much the same exept for a different preheat coil setup.
I tried to make a horizontal gun with a hinged opening to light it. I had a devil of a time trying to find out the internal workings of the Ursutz and finally found a decent set on this site. The Mk.I had a coil of 3/8ths inch copper tubing running the length of the combustion chamber with the tail end bent back through the center to make a "firelance" (for lack of a better term) to support combustion in a horizontal configuration. It is a pain trying to bend copper in that way without it turning into a mass of kinks. It worked for a while until I discovered the bug of most of the oil burners I have looked at: it would foul up and clog with coke. It got hot enough in the chamber to melt the tip of the center lance, however.
In the Mk.II I moved the preheat coil to the back of the chamber and made a lance out of thin steel tube (aka a piece of shaft from an old golf club). This setup works a little better, but it is a pain to get the whole thing burning efficiently and it is very delicate about the fuel/air mix. Too much air and it cools the chamber off too much, too much oil it pours out of the bottom of the burner door and makes a puddle. I also have to clean the oil holes in the lance every time I want to use it. Still, as you can see, it works, producing prodigious amounts of heat. It melted about a quart of aluminum in about ten minutes.
This is a not very clear pic of the inside of the furnace while it is running.
Lighting the Mk.I.
Mk.II open for inspection.
Inside view of the Mk.II modification.
Inside of the furnace after use.
Inside of the lid after use.
No access to a welder, so I have to get inventive. The wife also threatened me within an inch of my life if I used her muffin tins...
My pile of ingots.
My pouring shank.
Good crucibles for beginners, find a used restaurant equipment place and look for stainless containers that go into a hot table. Quite rugged, no welding involved, should be fairly long lasting, and best of all, CHEAP! Check the price on the shiny newer one. It is the smaller of the two and holds about a half of a quart, maybe. It even has a nice decorative edge on it. My larger one only cost a buck fifty more. I'll use the smaller one when I want to attempt brass.