Burner and Fuel Choice A10 Furnace

Discussion in 'Burners and their construction' started by Tops, Mar 8, 2023.

  1. Tops

    Tops Silver Banner Member

    Hello All,
    Working on an A10 sized furnace and putting the bigger 55 gallon drum one on hold, so now wondering about burner/fuel options for a 'medium' sized setup. Original thought was to use the cheapie propane burner from the mini furnace so 1.5" (38mm-ish) tuyere. Thinking it might be better to make tuyere bigger in case more burner is needed. Seems like a Delavan oil burner would need 2.5" (63mm) to get the nozzle and fittings in the pipe.

    Propane from a 20# tank would be choice #1. Propane from a 100# bottle would be second followed by an oil burner. Mostly doing aluminum, hoping to do more bronze in future. Guessing that cast iron would need the oil burner and might be borderline for space around crucible. Furnace is low mass 2" (50mm) fiber and .75" (19mm) hot faces. 10" (254mm) bore and 12" internal height with 2"(50mm) plinth and over crucible clearance.

    Could it work or is it 'another fine mess' I have gotten myself into?


    PS electric is not a good fit right now even though it would be nice for alu...
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I'd think a simple and inexpensive Reil type burner using 3/4-1" pipe for the burner tube would be fine.


    boroko, Petee716 and Tops like this.
  3. Tops

    Tops Silver Banner Member

    Thanks Kelly!
  4. Ironsides

    Ironsides Silver

    If you are a beginner to melting cast iron propane would be a good choice as it is easy to burn. Drawing large amounts of propane to melt cast iron using a small propane tank will cool the propane and starve the burner of fuel. Use the largest tank as it does not cool as much but will have the same problem when the tank is close to empty. The best way I found is to have a larger container to hold warm water around the propane tank when using smaller propane tanks.
    Tops likes this.
  5. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    .....and if you really want to melt iron with propane, go forced air burner instead of natually aspirated.

    Tops likes this.
  6. Tops

    Tops Silver Banner Member

    Thanks Guys, really appreciate it!
  7. Rasper

    Rasper Silver Banner Member

    As regards the size of your tuyere. I found out the hard way to make it big enough for whatever may happen. It is devilishly hard to enlarge one through fully cured Mizzou. I keep a pan of clay in my foundry. A day before a melt I add water and make mud, which I pack around the burner in the tuyere.

    I am a big fan of waste oil burners. The fact that my fuel is free is nice, but the real advantages are the simplicity and the huge amount of heat they can develop. I have been using Lionel Oliver designed burners to melt bronze for years: both the Hot Shot for my small furnace (A8) and the Brute for my big one. (A30).

    Waste oil is probably not for the guy who just wants to cast a few pounds of aluminum once in a while, Nor is it a good fit for the "rocket scientist" guys who spend most of their time and thought on sophisticated burner and furnace design and construction.

    The big furnace burning:

    The Hot Shot and The Brute:

    The valves. They have ball valves for fuel shut-off. I added needle valve for more precise fuel flow control:

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  8. Tops

    Tops Silver Banner Member

  9. Tops

    Tops Silver Banner Member

    I started in on a Big Brute design (Etu Brute...?) :)

    Right now it is only plumbed for liquid fuel (no propane). The leaf blower is 2 speed and says 180CFM. I was going to start at low speed and can also add a router speed control if I have read other posts correctly. I need to figure out a transition between round and whatever the blower is. I already have a drip tank for small engine work. Am I correct to assume that these will not run in free air, that there will need to be a vessel and preheat of dripped fuel to vapor before I'll see ignition? Does the drip tube need to seal tightly to the air tube? I was a little boisterous with the cutting torch connecting the drill holes for the slot. The front saddle will get removed once the burner is installed. The added ring up front is to make it about the same OD as the shiny new pipes I got.

    Petee716 likes this.
  10. Petee716

    Petee716 Gold Banner Member

    For sure won’t run in open air and yes, you need to preheat. Some, including Peck, suggest a wood fire but I personally hate having cinders blow out of my furnace. Propane works great. I don’t use a drip style burner, I use a Delavan siphon nozzle, but I still preheat, generally with propane because I run heavier oil than straight diesel, and lighting that burner cold can be a bit troublesome (and smokey). I actually have one burner to preheat with propane and another burner set up for oil. I get the furnace hot with propane and then swap them out. It takes all of 15 seconds to do the switch quickly and safely. If I tried to combine propane and oil in the same burner I’d cook the o-ring in my nozzle in short order. (Ask me how I know). Since you’re using a drip burner you wouldn’t have that issue, but your drip tube might coke up. Guys like Rasper or Ironsides might be able to tell you more about that.
    I found an exhaust pipe reducer that fit my air pipe on the small side and allowed my leaf blower to fit into the bigger side. It was in my “collection”. I wrapped the rectangular blower tube with Saran Wrap, stuck it into the reducer, and filled the void with Great Stuff. I can’t remember now but I think I stuffed a plastic bag into the small end first to keep it from filling with foam. You may want to cut or rasp off the very end of your blower’s air tube so you can remove it from the reducer, or leave it on to permanently attach it. In that case you could omit the Saran Wrap.
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  11. Tops

    Tops Silver Banner Member

    Thanks Pete. The black nozzle comes off the blower, leaving a shape with a flat top and bottom and rounded left and right sides. I thought about just wrapping that with tape and then using fiberglass cloth and resin to make a custom piece on the blower side. Burner side should be compatible with exhaust fittings. I have an old piece of steel flex exhaust I could cut a couple feet off and donate it to the burner project.
  12. Tops

    Tops Silver Banner Member

    I bought a new LP line with a 30PSI regulator and gauge, and it came with 2 tips that match the flare on the end of the line. I drilled and tapped for 1/8-NPT and installed the one without a jet.

    Do I need to seal up the entry slot for the drip tube? Does it need to be gas tight or just a bit better than shown?

  13. Petee716

    Petee716 Gold Banner Member

    I’d seal it right up with something like JB Weld.
    I have a quick-connector on my propane burner.
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  14. Petee716

    Petee716 Gold Banner Member

    If you were just blowing air the loss probably wouldn’t matter too much, but the propane warrants it.
    Tops likes this.
  15. Tops

    Tops Silver Banner Member

    That makes sense. When you mentioned JB Weld, my head went right to the movie Rocketeer and the scenes with the gum. A three minute recap:

    boroko likes this.
  16. Tops

    Tops Silver Banner Member

    I TIG welded in some of the gap -only balled the tungsten like three times :) - and then went after it with epoxy.
    I also finished up some prototype air piping from the leaf blower to the burner from heavy walled cardboard tube with homemade slip-fit joints and covered in cloth and resin.
    I think I am to the point of doing a drip test on the burner and then I need to finish (!) the furnace so I have a chamber for testing. I also need to finish the collar on the business end of the burner so it does not have a gap to leak gases out of the tuyere.

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