Practical diesel-fired furnace break-in

Discussion in 'Furnaces and their construction' started by Melterskelter, Jan 23, 2018.

  1. Melterskelter

    Melterskelter Gold Banner Member

    By the way, I melted iron today. First full-on hot run of my new furnace. Just melted a few ounces as proof to myself that the furnace would reach melt temperature. (Cork pops in background :)).

    Denis
     
    Last edited: Jan 26, 2018
  2. PatJ

    PatJ Silver

    That is a neat feeling to get some molten iron going.
    Congrats.
    I tried numerous times to melt iron with a propane burner, to no avail.
    It would get red hot, and then just sit there in solid form, forever.

    I later learned that I needed a propane burner and a blower for combustion air, but at that point I decided to build an oil burner.
     
  3. Melterskelter

    Melterskelter Gold Banner Member

    To say it was a neat feeling would be something of an understatement in my case.

    Thank you.
     
  4. Melterskelter

    Melterskelter Gold Banner Member

    Couple more melts yesterday using an unmeasured A/F mix but using some of the tips generously offered here. Both a 5 pound and 8 pound melt proceeded nicely with very fluid free-flowing water-like molten iron. With each firing I gain more ability to sense what takes to get high heat. But, though the results have been fairly good, I still don't know if I am operating at optimal efficiency or taking more time and fuel than needed.

    I did receive my automotive O2 sensor and Bluetooth interface device late today. I will be anxious to give it a try in the next few days. One challenge I have been mulling over is how to set up a reliable sampling system that will allow me to "sniff" the exhaust but ensure that the exhaust temp is down around 600 C or less at the sensor and that will not melt the intake to the sensor system. Most likely the system will have to be setup to swing into the exhaust and "inhale" for a while and make the reading and then swing back out of the stream. It can make a reading in only a few seconds (or even less), I believe. This system should be relatively blunder-proof so that it does not require babysitting or else there is a risk of becoming distracted and cooking the sensor.

    I would welcome any brainstorms you folks might have in regarding design options for the system.

    Added a few minutes later: I meant to put this in another thread I started "Measuring A/F Mix in an Oil Burner" I guess I will leave it here but post it there as well. Sorry.
     
    Last edited: Feb 2, 2018
  5. OCD

    OCD Silver

    I literally FRIED my very first (pearlite furnace :rolleyes:) with a weed burner and hair dryer.
    It was TOAST after that firing.
    TOTAL melt down, steel crucible and all. [​IMG]
    GONE, HISTORY!

    Then I came to my senses and built a REAL furnace and burner. :D
     
  6. PatJ

    PatJ Silver

    We need videos and/or photos or it doesn't count.
     
    Jason likes this.
  7. Frank Clark

    Frank Clark Copper

    With O2 sensors, it's not so much keeping the tip out of the heat as it is not overheating the whole sensor. In turbo cars (we have a couple), the O2 sensor manufactures say to mount them after the turbo. That simply is not an option in many cars. One of mine has 12" of 5" pipe after the turbo. No way to put an O2 sensor in there without it seeing lots of free air.

    Here is an example of what most folks do to 'cool' an O2 sensor:

    https://www.amazon.com/Innovate-Motorsports-3729-Heat-Sink-Extender/dp/B000CO9MFI

    product_image.jpg

    You could easily take that to an extreme to keep your sensor to a reasonable temp. The tip of the senor does not need to be in the exhaust stream, it can be set back in a T'd off section - it will read fine.
     
    Melterskelter likes this.
  8. master53yoda

    master53yoda Silver

    What would work best is if you cooled the exhaust stream with a heat exchanger prior to inserting the O2 sensor it will get a good reading without burning it up. You could put a piece of tubing around the exhaust stack and blow air between the exhaust stake and the outer tubing and cool off the exhaust stream. this isn't done in the automotive industry because they are trying to retain the heat in the exhaust stream for the catalytic converter. On boilers etc the heat has been stripped out of the exhaust by the time it has left the boiler so the temp issue doesn't exist. On our furnaces 75% to 85% of the heat is still in the exhaust stream when it leaves the furnace depending on the melt point of the metal we are working with.

    Art b
     
  9. Melterskelter

    Melterskelter Gold Banner Member

    Whoa, that is cool!
    Can you give me a bit more information on just what a T’d off section might look like on a performance engine exhaust. Perhaps pics of a typical tee installation or a link to a website discussing such installations.

    Art B, I have dreamed up an intermittent sniffer which would suck exhaust gas and pass it through a column filled with steel shot (BB’s) to cool the stream prior to it encountering the broadband sensor. Continuous sampling would be nicer, but I need to see how a tube (stainless?) would hold up to constant exhaust exposure. I think it would likely fail. So I am wondering how to draw the exhaust out of the stream continuously. That stream has to be somewhere near 3000 degrees.

    For the last couple weeks my energies have been focused on making preparations for casting relatively long narrow 35 pound individual pieces to be followed by 50 pounders I hope.. For the 35 pound part in question the molds will weigh 225 to 250 pounds. Since I work alone and I am a weakling unable to finely manipulate 125 pound copes onto similar drags, I am just tomorrow finishing a chain fall/overhead track trolley, flasks, and a ram-up table and moving the whole operation to a more suitable rural location. Once moved, there will be the challenge of trial pours with inevitable glitches and refinements to get that process working. So, the sniffer may have to wait a couple weeks...
     
  10. Petee716

    Petee716 Gold Banner Member

    This is the first I've heard of the chain fall/ overhead trolley. You been holding out on us? Lol

    Pete
     
  11. Melterskelter

    Melterskelter Gold Banner Member

    Holding out? Hardly!:) I haven’t even finished putting it all together. But it is almost all done. If you think of how a meat packing house moves sides of beef, you will get the general picture. I am using sliding barn door track as the overhead rail. Two of the door trucks support a two foot length of 2x8 which itself has an eye bolt. Chainfall hangs from eyebolt. Spreader bar hangs from chainfall. On the ends of the flasks are secured 3/4” Dia stubs located at their axis of rotation. So the cope and drag can be lifted and flipped individually and by using a bracket that spans the cope and drag pins the whole combined cope and drag can be lifted and rotated if needed. The trolley moves easily laterally so that once a mold is ready to pour, it can be lifted off the bench and moved laterally to then be lowered to the floor. Anyway that is all the theory. We shall see how it works in practice.
     
    Last edited: Feb 25, 2018
  12. Petee716

    Petee716 Gold Banner Member

    It really got my attention because I have similar goals regarding flipping and moving flasks. In fact I have barn door rails and trucks just waiting to be used.

    Pete
     

Share This Page