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Thread: Aluminum Skeleton Project Furnace and Tool Builds

  1. #11
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    Point a hair dryer at the T opening and see what you get. If it settles down, you need a blower.
    Bones

  2. #12
    Senior Member Zapins's Avatar
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    The gloves look good but you want a full length apron. Metal is most likely to hit your legs, so you want something to stop that. Don't get the ones that strap on each leg - they suck and are easy to trip on, just get a normal full size leather apron. The welding helmet will restrict your vision too much. A clear plastic face shield works well http://www.homedepot.com/p/3M-Clear-...0025/202195394. It won't fog up and will divert metal droplets. If more than a few droplets are going for your face then something went terribly terribly wrong and no helmet will protect you adequately.

    Steel toed boots are also advisable since if you drop a crucible while pouring the metal will splat and travel along the ground towards your toes. A welding jacket or long sleeved thick garment to cover the arms will stop splatter as well, but be careful it is very easy to overheat inside all that protection. I didn't realize dehydration and overheating were so easy to happen until it happened to me. Luckily I was alright but still eye opening, heat exhaustion is a real thing.

    Basically, if you use your head and are careful, pour on a slight down slope and don't run around like a mad man you should be alright. Ideally you won't ever need the protective gear to save you.

    As for the air issue, most furnaces have a 2-3" wide air pipe going into the furnace body from what I've seen. The burner tube goes inside the 2-3" outer tube.

  3. #13
    Quote Originally Posted by FishbonzWVa View Post
    Point a hair dryer at the T opening and see what you get. If it settles down, you need a blower.
    I'll test this out next time I fire it up. Does getting this thing red hot mean I can melt aluminum?

    Quote Originally Posted by Zapins
    The gloves look good but you want a full length apron. Metal is most likely to hit your legs, so you want something to stop that. Don't get the ones that strap on each leg - they suck and are easy to trip on, just get a normal full size leather apron. The welding helmet will restrict your vision too much. You want a clear plastic face shield http://www.homedepot.com/p/3M-Clear-...0025/202195394. It won't fog up and will divert metal droplets. Steel toed boots are also advisable. Possibly a welding jacket or long sleeved thick garment to cover the arms.

    As for the air issue, most furnaces have a 2-3" wide air pipe going into the furnace body from what I've seen. The burner tube goes inside the 2-3" outer tube.
    Thank you for the advice on the safety equipment. I'll adjust my purchase choices and come back with them.

    Also, I updated the first post and Imgur albums with the written plans.

  4. #14
    Senior Member Zapins's Avatar
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    Caught me while I was editing my post. Reread it I added a few things.

    Red hot probably means you can melt aluminum. It doesn't have that high of a melting point. It might take longer than with a blower and might be more inefficient but I think it will probably work as is.

    With the blower adjustments you can get it to yellow/white hot.

  5. #15
    Quote Originally Posted by Zapins View Post
    Caught me while I was editing my post. Reread it I added a few things.

    Red hot probably means you can melt aluminum. It doesn't have that high of a melting point. It might take longer than with a blower and might be more inefficient but I think it will probably work as is.

    With the blower adjustments you can get it to yellow/white hot.
    I will defiantly try out the air blower. Shouldn't be hard to put together.

    This apron is a little longer : https://www.amazon.com/gp/product/B0...=ATVPDKIKX0DER. Thoughts?

    I can pick up the Helmet at the local Home Depot. Thank you!

  6. #16
    Senior Member Zapins's Avatar
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    Found 2 different ones that are 48" long (8" longer than the one you linked). Would provide better ankle protection and if it is too long, you can always cut off the excess.

    https://www.amazon.com/Radnor-Bourbo...+leather+apron

    https://www.amazon.com/Tillman-3848-...+leather+apron

  7. #17
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    Great to see your progress. With regard to boots I wear them with the laces untied but tucked in so I can kick them off if metal gets in, some people were spats as well.

    Another quick note, it's a furnace not a forge, given this is an school project you may want avoid the term forge in your reports. (I'm being pedantic but it isn't correct terminology)

  8. #18
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    Martin, I'll try to explain what's going on with the burner.
    The orifice you made by drilling with a 1/16" bit works fine in the open air. When you put it in the confines of the furnace, there is not enough room for the gas to burn. This is known as a rich atmosphere. Being rich causes the molten aluminum to absorb the hydrogen and you will have lots of porosity in the finished product. Yes, the furnace will get red hot and melt but it's not right.
    How to fix it:
    1. Get another cap and drill with a #58 or 3/64" bit, or add a blower to supply more air.

    It took a long time to get this through my head. I thought the more heat I threw in the furnace the better off I was. Not true. The flame has to be dialed in to get clean melts. If you can keep the flame on the lean side you don't have to de-gas.
    Bones

  9. #19
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    Fish did you use a #58 for your burner? I've heard a #57 bit is the way to go, not sure if there is anything to this or not, I just used it and didn't test out other sizes personally so I'd be interested in the difference. I don't see why the hole size matters that much but I'm not sure.

    I think the reason was a #57 ensures the flame doesn't burn inside the burner tube like other sizes. Not sure if this applies to your burner or not. Read the additional notes at the bottom of this thread http://www.backyardmetalcasting.com/oliverburner1.html . The bit can be ordered online but probably not bought from a shop, they aren't very common bits.

  10. #20
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    I cheated and bought a propane orifice from my local hardware store. They had a box of them in different thread sizes but all the same hole size.
    Even with that orifice my burner can't be run but 1/2 open or it gets rich. I'm happy to run it low rather than add a blower. KISS principle.

    Sizes
    http://www.joppaglass.com/burner/lowp_chrt.html

    1/16" = 0.0625
    Bones

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