Post Mortem on Thick Dense Castable Furnace

Discussion in 'Furnaces and their construction' started by Melterskelter, May 24, 2019.

  1. Jason

    Jason Gold

    Good observations. I think 1/2" is too thin unless you want to replace it regularly.
    That's my method Denis. Enrichen until I get a bit of black smoke and lean her out until it just runs clean. Working good for my bronze. Richard is right, an oxidizing flame is the last thing you want for bronze. It Fs up the metal. What it does I can only guess... Cooks the silicon out of it maybe?
     
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I use wish I wanted to cast something in iron so I culd join you fellas in the materials and burner challenges.....or maybe not. It is fun to watch the carnage and learn.

    Ya-know MS, I don't know how much maintenance was required along the way on the dense castsable furnace but 75-100 iron melts seems pretty darn good, especially since it sounds like it may have had additional life. You may be bucking the trade between a melt times and fuel consumption vs furnace life. Oddly enough, there may be good benefit in a BA floor to resist metal burn in. Even better if it was a loose tile so it could be replaced.

    Remind me, what are you burning for fuel? Diesel or waste oil?

    This statement resonates with me a bit because I've noticed even in an electric melting furnace, on the first melt, there is no reason for temperature control because the furnace temp is always just a couple hundred degrees above the melt temp. This assumes there is a reasonable charge of metal in the crucible. On subsequent melts with the furnace mass at temperature, the initial temp differential between furnace and crucible/charge temp will be greater but not the final temperature.

    With high power oil burners, it would be interesting to know what the flue gas temperature was throughout the melt cycle.

    Best,
    Kelly
     
  3. PatJ

    PatJ Silver

    Maybe I am missing something, but the furnace you broke up looked perfectly serviceable.
    What exactly caused you to consider tossing it.
    Was the refractory crumbling?

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  4. Melterskelter

    Melterskelter Gold Banner Member

    That answer was buried in post 3. “The main reasons I retired that furnace was it was too short inside and had too much thermal mass.”.

    In addition it was somewhat clunky to use. The lid lift and lid design were lacking. The lid sheet metal top was (possibly replaceable) was burned through as well due to poor vent design. If I had unlimited space, which I do not, I could have kept for smaller crucibles. Since it was too short for a good plinth, it was really hard on crucibles. Some kludge to raise the furnace walls was not happening.

    Denis
     
  5. PatJ

    PatJ Silver

    That makes sense.
    It can be easier to start over than to try and fix a furnace.
    I did fix mine because there were no real problems with it other than the lid sticking problem, which I was able to fix easily.

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