Larger Moya???

Discussion in 'Burners and their construction' started by HT1, Jun 14, 2019.

  1. Melterskelter

    Melterskelter Gold Banner Member


    I use a 20V supposed-to-be-battery-powered leaf blower connected to a 24V DC power supply. I have to throttle it down to prevent excess air and I get good swirl too.

  2. rocco

    rocco Silver

    Slightly off topic question here, Denis, do you happen to know how much current your blower draws at 24V?
  3. I'm currently testing some refractory concrete liners, there's a 2.5" bore and 3" bore about 8 inches long. The fuel nozzle can be moved up and down the length of the liner to tune it. I can get some molten iron but still not hot enough so far, it seems combustion flames don't start inside the tuyere tube but further along in the furnace chamber.

    refractory liner 1.jpg
    Last edited: Feb 11, 2021
  4. HT1

    HT1 Silver Banner Member

    Ok I moved forward again with this. anyone on any social media would know:rolleyes:

    we have a 13 inch bore of IFB, 1.5 inch Moya burners , and a 166CFM blower 2 inch outlet, drops down to 1.5 inch at the gate valves

    I fired the burners up today JUST on Propane, how I intend to run it ,

    To get a steady flame, I had to choke the inlet air at the gate valves , about 75%, and spun down the blower with a speed control to about 66%, and cranked the gas up to 25PSI , I would really like to let the blower run all out , for longer life.

    I think the 1/16 inch orifices' in the propane inlet is too small (any opinions)

    additionally, when will the needle valves I installed for fine tuning become a limiting issue, the outlet in them, is about a 1/8 inch hole , no info on amazon that i could see

    Thanks in advance
    V/r HT1
    Billy Elmore and Mark's castings like this.
  5. Tobho Mott

    Tobho Mott Gold Banner Member

    Furnace is looking great!

    I don't have any sort of orifice at all for the propane entering either of my moya burners, the gas just dumps into the burner tube. The 1" Moya runs about neutral at around 5psi using a hair dryer on full blast on the 'cool' setting this way, for what It's worth.

    You can have a look at how the propane enters it here from 1:23 to 1:32 if you want:

    I never did a full melt with my similarly plumbed 2-1/4" Moya just running propane, and I have only really even used it a couple times using wvo/diesel, but I haven't run anything other than propane using the 1" since I built my blanket and satanite furnace, where propane melt times starting from cold are only 5 minutes longer than furnace preheat so I can turn on the drip times in my 5 gallon bucket vac powered waste oil furnace.

    HT1 likes this.
  6. HT1

    HT1 Silver Banner Member

    Ok this morning is started stepping up the burner orafice . First up to 5/64. I got expected results. And could almost run the blower all out at 25PSI. Went up to 3/32 and got much less improvement??? 7/64 I got no change at all could not quite run the blower all out with propane at 25PSI..

    While assembling for what the 5th time I got some plumber dope in the end of one of the propane pipes. So I stuck the air nozzle in the end and had a ton of back pressure… ? My previous concern about needle valves was playing out . So I removed the needle valves . The orifices' are drilled to 1/8. I can run the blower all out at about 10-12 PSI of propane. The gate valves are still throttled. But I’m much closer to having the burner “tuned “
    BTW compared to the old furnace this is insanely hot instantly. Can’t wait to get everything tuned. The lid well sealed and do a test. Then we will get a full build

    V/r HT1

    Tobho Mott and Mark's castings like this.
  7. oldironfarmer

    oldironfarmer Silver Banner Member

    Furnace is looking good!

    Choking a blower puts les load on it and it lasts longer. It's a little contrary to what is intuitive.
  8. HT1

    HT1 Silver Banner Member

    I tested the New furnace today, I achieved what I wanted, I went from cold to Pouring an A16 of yellow brass in 32 minutes, the furnace is insanely overpowered, even with the air gate valves mostly closed, I had to rheostat down the blower to keep the furnace from eating itself, NO REALLY at full blast, the leaks around the lid made it impossible to get near the furnace, it spun brass scrap out of the crucible and up onto the lid , running the blower at about 2/3 and tweaking the propane, I got a pour. But I need better PPE, this furnace would have destroyed welding gloves in a second, luckily I have a dozen pair or proximity gloves for fighting oil well fires, but I will need a professional faceshield, and an aluminized jacket . Guys, this furnace is insane, no DIYer should build a furnace this overpowered , big thanks to Andy for all his help, especially for the brickwork,

    I will do a build post, with prices, it was really really expensive, seemed like every trip to the hardware store was a$100 and their was alot of them, though there was some serious waste as things changes and got abandoned

    V/r HT1

  9. That looks great!, the refractory looks thick enough that the outside wall would be reasonably cool?. It looks like it would run well on one burner after initial warmup but that might? damage the second burner with flame wash if it's shut off.
  10. HT1

    HT1 Silver Banner Member

    the warm up is literally seconds, in one minute the walls are glowing red, you cannot stand anywhere near the furnace, there is no glancing in to check the heat, you have to wear a faceshield and then you have to be quick or the shield will get the melties
    this furnace is frightening!
    I've cast steel and monel in a 400 LB bull ladle, and been more comfortable then I was around this beast

    since I cant set anything on the lid to warm it I placed my ingot molds in the furnace while I lit it off, by the time I gathered the tongs and PPE to take them out they where already glowing red, well under two minutes,

    Before I got the air tuned down, it would spray so much fire out from under the lid I could not get near the furnace, the 166CFM blower is obviously too powerful,
    I had always thought Mifco's claims for their furnaces where overrated, I've actually proven myself wrong

    V/r HT1
    Tobho Mott likes this.
  11. That furnace is going to save a lot of time melting metal, especially subsequent melts. If it's anything like my friend's one, as the slag builds up with use on the furnace interior, it will glow even brighter and hotter: yellow to white.

    Last edited: Sep 6, 2021
  12. Petee716

    Petee716 Gold Banner Member

    Congrats. It sounds like a success. Too much is ok, you can tone it down to balance out reasonable melt times vs fuel consumption and safety considerations. It won’t take you long to find the right balance.

  13. oldironfarmer

    oldironfarmer Silver Banner Member


    Is it all brick inside?
  14. HT1

    HT1 Silver Banner Member

    no, I cast the sections where the burners go in from Kastolite , so it is only about 2/3 brick

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