Ceramic kiln Any good for building a furnace?

Discussion in 'Furnaces and their construction' started by welderskelter, Nov 1, 2022.

  1. welderskelter

    welderskelter Copper

    I just remembered I have an old ceramic kiln in the back of an old van out here. Was wondering if they get hot enough to melt aluminum? Dont know anything about ceramics.
  2. Ted Brown

    Ted Brown Copper

    I was thinking the same thing. Most of them I see say 2200f, so that should work for me (aluminum also). My plan was the turn the kiln upside down and build a lift to raise and lower it to the top (which is now the bottom). The crucible would sit on the old top upside down and then lower the kiln down and turn up the heat. This would eliminate the need to reach down inside and easier control of the crucible.

    I'm a newbie, so I will wait for someone to shoot holes in that plan.

  3. welderskelter

    welderskelter Copper

    I was just planning on using the insulation to build with. Never thought of using electricity to heat the aluminum with. Would be fun to hear some comments on that one. I figure it would be expensive . I think that is the reason you dont see many people doing ceramics now days.
  4. crazybillybob

    crazybillybob Silver Banner Member

    I picked up an old Kiln for like $75 awhile back. It was on or off. High or low (all coils or 1 coil). I wasn't even sure if it worked. But for the price the Insulation was worth it. Turned out that it did work. Even came with a spare set of new elements. For around $150 I'm converting it to electronic control with programable ramps. That way I can try some lost wax or lost PLA. About the time that I got all the parts I had to put the project on Hold as I moved and I'm still waiting to get the new shop built (anytime now!) But you should be able to melt aluminum in a kiln. Their just not real fast at it.
    Tobho Mott likes this.
  5. Al2O3

    Al2O3 Administrator Staff Member

    Kilns will easily melt aluminum. You may (most likely) have longer melt times than fuel fired furnaces. The furnace atomosphere of a kiln can have advantages for aluminum melting as well. There are fewer sources of H2 that leads to H2 porosity. You never have to store or worry about running out of fuel and start with a switch.

    I'm not sure whether the typical kiln construction will still retain the refractory wall & floor if it is upside down.

    Electricity is actually very inexpensive for melting, at least in my case. I use a purpose built, lift off, 8kw resistive electric furnace exclusively for aluminum casting. There are links in my signature. In round numbers, it will melt 10lbs of aluminum from a cold start in about 30 minutes, faster for subsequent melts. It can accomodate an A20.

    For me, elctricty is about 8 cents/kw-hr (USD). For my furnace that 32 cents for 10lb melt. For 8kw it costs 64 cents/hour for continuous operation but when the furnace itself has been warmed up and comes to temperature there is a duty cycle, so the actual power consumption is typically half that.

    I dont think you'll do better on operating cost if you buy furnace fuel, unless you burn free waste oil.

  6. BattyZ

    BattyZ Silver Banner Member

  7. metallab

    metallab Silver

    Using an electric furnace should work well for aluminum. I have one which I use for copper, it is 1400W and melts 500g of copper in less than an hour (starting from a cold furnace).
    Larger quantities require more power obvously.

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