Kwiky burner with a twist

Discussion in 'Burners and their construction' started by OMM, May 22, 2019.

  1. OMM

    OMM Silver Banner Member

    I am starting down this road, that a lot at you are very well rehearsed.

    My plan is to use the kwiky burner. I see a lot of guys adding additional forced air feeding the burning tube.
    The additional forced air how does this assist in the burn? Wouldn’t more air from the nozzle be able to assist better?

    I have read 2 to 4 inches from nozzle to the ignition point inside the burn chamber of the furnace ideal.

    The guys who drip feed, the burn chamber is outside the furnace.

    I really want to build small and I’m OK with some thermal losses. I have plenty of compressed air. I do plan on using waste oil.

    I guess my main question is, has anybody used the kwiky and started ignition burn chamber outside the furnace with good results?

    Second question is, what diameter burner tube are you using and what material is it made out of?

    Third question is, besides additional fed air, has anybody added a spin vein or Venturi effect? And or a tipped down nozzle on the burn tube?

    Fourth question, what kind of fire brick do you use? I’ve been offered A unlimited amount (for my purpose)(9 ton.). 10 different sizes and three different weights that are coming out of a furnace, scheduled for full replacement. I’ve been told some of the bricks is as light as Styrofoam and can be carved with your finger nail. All of the brick is rated for 3200 F. The walls of this furnace are over 1 foot thick. As well, I was told most of the brick on the outer walls is pretty much brand new, but it all gets scrapped.

    I’ve seen a few guys on YouTube creating somewhat of a Whistle chamber which is quite interesting...
    Last edited: May 22, 2019
  2. oldironfarmer

    oldironfarmer Silver Banner Member

    Low pressure air from a blower is less expensive than more air from a compressor. The nozzle is to atomize the fuel. I think you'll find getting enough combustion air through the atomizer will cause it to not be a stable as if it were only for pulling fuel through.

    I don't know what you are talking about "burn chamber". There is no burn chamber, just the furnace interior. I use a pressurized drip and it is incredibly simple and works very well, just spit cold oil into a hot furnace with lots of air.

    Trying to burn outside the furnace you need to have a refractory chamber as there are no metals which will stand the heat for long. Not even titanium. Having the hot box outside is very uncomfortable and you have to be able to open it to clean out the ash which the waste oil deposits. I use a natural ash deposit on the wall of my furnace as an ignition point, it stays white hot. But you can melt a crucible with a

    I use 1-1/4" OD plain steel that's essentially a modified Moya burner.

    Lots of guys have tried spinners to try to atomize the fuel. If you want to atomize buy a Delavan nozzle and filter your oil. They have a well engineered design you would spend years to match.

    Filter your oil anyway.

    Lots of guys on YouTube don't really get the results they claim. Maybe for ten minutes.

    Spend some time and read through the posts in this section.
  3. Jason

    Jason Gold Banner Member

    Well.... The motive force to move the fuel in the kwiky is compressed air. That does the job of ONLY moving the fuel. Without the addition of forced air, forget it. You'll never get hot enough to melt anything but paper. If you watch a few of my videos, you'll see what the flame looks like without forced air. For instance, I light outside, shove it in and the flame is lazy, tall and sooty. By adding a large amount of forced air from my microwave blower motor, the flame retreats back into the furnace where you want it and the temp soars. You'll never be able to raise the compressed air high enough to do the same job. It's about air volume you are adding and not pressure so save yourself some time and run a small blower.

    My pipe is a 2in exhaust tube from the autopart store. It's a faff to install it inside, but doable. If you read my thread, build it as close to the chamber as you can get it. If you don't, the oil will wash the insides of your pipe and leak all over the ground. (been there, done that) Mine refused to burn oil back then, moving it close solved that problem.

    I don't understand the questions "started burn chamber outside???" sorry.

    I don't run a spin thingy, it's not really necessary. I got plenty of spin from mounting the tuyere on the side of the furnace. When you build the tuyere, be sure that entrance is about 1/2"-1" UP OFF the floor of the furnace. This way, if you ever have a spill of hot metal, it won't back into your burner. That would be a bad thing. If you want spinny things, buy a delevan or hago. Those do that fancy stuff. You'll need a plinth. You will set the crucible on top of this. It's job is to keep the crucible OUT of the path of the flame. It helps it live longer.

    I lined my tank with almost 2" of kaowool (2300degree) and then a good inch of mizzou refractory cement. Good for 3000degrees, it heats fast. You don't want to touch the outside of the furnace while it's running. It gets about 300f. If you can get free stuff, go for it! If it starts to fall apart opposite from where your burner is inside, you can always slap on some mizzou or ITC to help protect that area.

    Understand when you run a furnace to melt metal, you want a neutral flame. This means, flames licking outside the exhaust hole about 3inches and no more. I run a set blower speed and adjust fuel mixture from there. Too rich and you get black soot. Too lean and you get no flame licking out the exhaust and you'll screw up your metal. Both of these scenarios result in a cooler furnace. Easier to understand when you are the guy playing with the mixture. When you build your kwicky, shoot for about 15-20psi compressed air for the motive force to move WATER.... More than that and you have probably shaped the mig tip wrong or have the end screwed up. It will run nicely on 20psi and not run your compressor to death. Hopefully your compressor is quiet. I use a 60gallon compressor and it runs for 45seconds once every 5 minutes or so. Mine is pretty quiet, but the airless ones (oilless) are annoying as hell to me. Yes I said WATER. Get yours built, hook it up to a bucket with a hose and adjust the square nut to piss around 1.5 gallons of water per hour. This will give you a good starting point. Measure water, and run it with water spraying for 10minutes and multiply time 6 to get your GPH. Then when you switch to nasty black oil, you should be about right and not need to mess with the square end anymore. I haven't touched mine in 3years! I run Jet-A (diesel) and make the switch to used motor oil after about 10minutes. You will not be able to get this going straight on used motor oil. Some guys preheat with propane then switch to oil. Mine starts easily with free jet fuel so no reason to screw with propane. Further reading on flame adjustment is here.

    Now this part is important. EXHAUST hole! 4inches got it? Oil burners like lots of breathing room. Same goes for the diameter of your chamber. Don't build it tight. Allow at least 2 inches on each side of the crucible from the furnace walls. Best way to do this, buy your crucible NOW! I don't know what you are casting or how big you are planning to go. It all comes down to what you feel comfortable lifting either by hand or with a crane. The first time I lifted a crucible full of bronze, I'll say it was a pretty sobering experience. One slip and it's goodbye feet and legs!:eek:
  4. OMM

    OMM Silver Banner Member

    What I meant by burn chamber is either before the furnace or actually in the furnace. I think I see what you’re saying. Keeping the burn actually inside the furnace would be beneficial. I was thinking of using tungsten as a flash point glow Rod prior to the furnace. It could be easily replaceable, what are your thoughts?
  5. Jason

    Jason Gold Banner Member

    Yes... You want the burn to occure in the furnace, not inside the pipe. On diesel, it will look like the flame is coming from the tip or pretty close. After the furnace is hot, you'll switch to oil and the oil combusts inside the hot environment of the furnace. First time you see it, you'll understand it's no longer a flame thrower running on oil.

    No reason for a continuous ignition source like a glow rod. This thing is self sustaining as long as there is fuel and proper airflow. If you get a flameout and you will when first learning, If on diesel, it will look like a mushroom cloud. Your plan is to get it stable with the furnace lid OPEN, introduce the blown air and slowly close the lid. Adjust mixture. IF it flames out. Immediately shut off the fuel and open the lid. Leave the air from the blower running. Trying to reignite while it's dumping fuel in with the compressed air is asking to blow the lid off if conditions are right. Granted, diesel is not at all like gasoline, it still burns, but let's not take any chances.
  6. OMM

    OMM Silver Banner Member

    Old and Jason, Thanks for your replies.

    I think I have enough air. I have an 80 gallon variable speed compressor that can get close to 19 CFM at 90 psi. It charges to 155 psi.

    Thanks ‘Jason I will do these tests. Are you using a stainless steel or regular burn tube?
  7. Jason

    Jason Gold Banner Member

    That's Andy from Oklahoma. I know he burns oil, I don't know what his burner is however. He's too good for the lowly kwiky burner.:D
    You have more than enough air. Like I said, if you can't get it to move warmed (90degree) used motor oil on 20psi, something is wrong. In the winter months in texas, I put a space heater on the side of my black tank. If you choose to pressurize your fuel tank setup, that's a whole different cat. I'm using gravity as you've seen in the videos, I place the oil higher for more head pressure. We have one guy here in mexico that runs a drip burner and he hauls his oil up to his 2nd story at his house. Again, another cat of a different color.
    My burner tube is just mild steel from oreillys autoparts. Nothing fancy here.
  8. OMM

    OMM Silver Banner Member

    Jason, you mentioned shipping the Mig tip wrong. What exactly can go wrong?

    I am somewhat of a numbers guy. I can shape this tip two 15 1/2°, 22 1/2° or 30° Or I can get into degrees minutes and seconds and grind the tip. The Mig tips I have on hand are 0.023, 0.025 and 0.035. What size are you using?
  9. Jason

    Jason Gold Banner Member

    Uh yeah.. That would be SHAPING the tip. It is possible to make it too pointy or too blunt. Get it wrong and it will take too much air to move too little fuel. I used whatever David said to in his build video. I screwed up my first one and also learned the hard way. Don't remember what was the golden ticket. Try going with what he says, you can putz with it as necessary.;)
  10. OMM

    OMM Silver Banner Member

    David gave no inside geometry for the plug angular taper fit to Mig Tip angular relationship. This is where I get a little confused. Maybe Precision is not so important?

    I am in Canada. From what you’re suggesting, oil won’t flow very well in my parts. Lol
  11. Jason

    Jason Gold Banner Member

    lol... Not when that black goo is 25F TobhoMott (jeff) is another oil burner in your parts. But I don't think he's running a kwiky either.

    Nahh.. Precision isn't really that important with this thing.
  12. OMM

    OMM Silver Banner Member

    My shop temperature is usually around 22°C or 72°F . Sometimes it is -20 to-30°C (-7 to -22F) outside. We adapt...

    We also get 34°C or 93°F. Fun times… Where else in the world would you get 115°F difference in temperature in seasons?
    Last edited: May 22, 2019
  13. Tobho Mott

    Tobho Mott Silver Banner Member

    Mine's a drip oil burner, but no external firebox, I preheat with propane and once it's hot enough inside the furnace I start an oil drip, by then it is hot enough in there to vaporize the drips so no atomization is needed.

    I've seen a few drip type burners that do use the external burn chamber, I think they are called ursutz burners.

    Mine works more like one of these:

    Actually even more like this one:

  14. oldironfarmer

    oldironfarmer Silver Banner Member

    We get to 0F and 115F, so Oklahoma.

    You can buy tapered MIG tips. They have a nice taper. About $1 each.
  15. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    The low ambient temp this Winter was -29F. It was 90F a couple days ago. Mid90sF is common in July/Aug and triple digits on rare occasion. I feel your pain. Iowa, central USA.

  16. Tobho Mott

    Tobho Mott Silver Banner Member

    OMM, you could also try asking David about the angles etc. in the comments for his Kwiky build video, he's pretty good about answering those and I'm sure he's gotten quite a bit of good feedback from people since he posted it. He also posts on the alloyAvenue forum, but only infrequently. I don't think he's a member here (yet).

  17. OMM

    OMM Silver Banner Member

    Jason, do you have any regrets about having the nozzle so close to the furnace? Does this get your oil feedline a little too hot? Or, do you block it with installation of some sort?

    Can you show, A picture or video of your set up?

    This is what I’m thinking right now with my set up

  18. Jason

    Jason Gold Banner Member

    I have zero regrets about positioning it so close. I put some kaowool by the valves in one of the videos, but never again. Did ya watch the first 10minutes of this?

    Here is some photos I just took of mine tonight for ya. The orientation is just like David shows in the video except I have both oil and jet fuel
    plumbed to the same hole. When making the switch over to used motor oil, I slowly open one shutoff valve and close off the other. Works for me. Hard to see my compressed air input, but it's right next to that junk harbor freight not really an air regulator regulator..
    Mixture is preset with the needle valves. It seldom needs much tweaking unless it's super cold/hot outside. Is this overkill? YUP, but it works great so I'm sticking with it for now.
    Your setup has me a bit confused. I'm guessing the airchuck closest to your nozzle is the fuel supply? And the one on the far right is for compressed air.
    What's with the 90 elbow pointing up? What is that for?



    Securing this thing to the pipe can be a PITA. I trapped a fender washer inside and used a collar on the outside of the pipe with a setscrew to locate it in the exhaust pipe.
  19. OMM

    OMM Silver Banner Member

    FF2CFA52-F662-4195-8729-D4784F42B4C8.jpeg Jason, sorry. I’m doing this pretty on the fly... that open nozzle is for a pressure regulator. I’m trying to work with as many leftover job pieces as possible. I did have to purchase the gauge. I just finished screwing it on.

    Is that painters tape where are you made your modification to move the spray nozzle closer to the furnace?
  20. OMM

    OMM Silver Banner Member

    Thanks for the video. LOL I love Coco!

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