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Thread: Mailbox forge, need advice

  1. #1

    Mailbox forge, need advice

    I'm going to make a heat treating propane forge from two steel mailboxes. The specs of the inside of each box is 18.5" long, 6" wide, 7.5" high, and 24.5" circumfrance. The mailboxes were only $6 each and the door will be very helpful.

    Now the thing I need help with is the hose connections. I plan on putting a reil burner on each end of the mailboxes so that it will heat more of the blade. But I can't figure out how I should seperate the burners this far apart from each other. Should I use copper pipe or hose? And is there a list of the pieces for this or a picture of the setup?

    I got the end pieces of wool cut out and some extra to add to the bottom and just need to order some more for the walls.
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    Glen Mergnes

  2. #2
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    Not speaking from experience, here, but I'd imagine a length of copper pipe would be a good idea. It would help to separate the hose from the heat.
    Jim Mearkle

    Swing low, sweet nebenhut!

    "A sharp point is a peremptory fact, which makes quick work of illusions..."
    Baron de Bazancourt

  3. #3
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    Here is a pic of my twin-Reil set up-the angle isn't great for looking at the burner set up but you can get the idea. My burners are only separated by about 6", but all the fittings past the regulator are brass, copper, or cast iron. I try to keep the hose well away from the forge itself.
    Using 2 layers of wool/insulation would probably be worthwhile, especially with such thin-walled bodies.
    Justin King

    just killing time until my next bad idea....

  4. #4
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    Forgot the freakin' picture AGAIN
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    Justin King

    just killing time until my next bad idea....

  5. #5
    Actually I plan on puting the burners on the ends of the mailbox instead of on the side wall so that I can heat more of the piece without having to run the blade back and fourth through the flame. I think the perpendicular flame heats about 6" of a blade and i'm assuming the parallele flame could probably heat 12" worth. Since clayartcenter is down and Elliscustomknives has'nt responded back yet, I found a pretty good deal on ebay for some Kaowool: http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WD1V

    It's actually a better deal and since it comes in 1/4" thickness I can put some 3000F refractory cement between the layers. I'm not sure if this would improve it much though. I can also make a microforge with it.
    Glen Mergnes

  6. #6
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    As most mailboxs are "Galvinised", I'd be very, very, VERY carful of them getting warm. Galvinize poisoning is nasty. Ask any welder who had to work on the stuff. The fumes will make you one sick puppy.
    "Do not suffer yourselves to be wheedled out of your liberty by any pretences of politeness, delicacy or decency.
    These, as they are often used, are but three names for hypocrisy, chicanery, and cowardice.” John Adams, 1789

    "Everything the enemy least expects will succeed the best."

    Frederick the Great 1747

  7. #7
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    Hadn't thought of that, but Arik is probably right on about the galvanizing...
    Justin King

    just killing time until my next bad idea....

  8. #8
    I think it's just zinc plating. My charcoal bucket forges were galvanized but that burned off quickly with a green flame after the first run.
    Glen Mergnes

  9. #9
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    Galvanized steel is is zinc-plated steel.

    There is a reason that Weirton Steel used to pay almost double to anyone willing to work in either the chrome plant or the tin (AKA: galvanized) plant .....they died.

    True they didn't have to pay them long enough to worry about pensions.

  10. #10
    Hey, do I really need two burners? On Don Fogg's site there are two long heat treating forges with only one burner. http://www.dfoggknives.com/photogall.../DrumForge.htm

    Would a 2" diameter space inside with a venturi intake burner heat more of the length or would a wider space like 4" work better?
    Glen Mergnes

  11. #11
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    Hi Glen..

    I was just going to post a link to Don's drum forge, but it looks like you already found it.

    I think that two burners is going to be overkill if this is a heat treating forge. Don's barrel forge is only one burner, and a much larger area than yours. I think that Don's forge concept may also not work as well with such a small area internally, but I'm not certain. I'd be worried that one end would be hot were the burner can't help but reflect off of the refractory, where as in Don's forge the burner has much more space around it, making for a more wide heat distribution.

    The best solution I've found for forge bodies short of scavenging is to find a local steel forming company to roll a tube out of sheet metal, and then weld it into pipe. I used a 14 gauge sheet 24" x 31.4" to make a 24" long, 10" diameter pipe for my general purpose forge, the total cost for the shell was about 10$, but I bought the steel at a good discount. When it's time for me to make a dedicated heat treating forge, I'll do the same thing, just have them roll me a larger pipe, probably 24" diameter.

    I'll post pictures of the new forge later tonight, I hope.

    josh
    The smith also sitteth by the anvil,
    And fighteth with the heat of the furnace,
    And the noise of the hammer and the anvil is ever in his ears,
    And his eyes look still upon the pattern of the thing that he maketh.
    He setteth his mind to finish his work,
    And waiteth to polish it perfectly.

  12. #12
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    Jim, if you have every hot worked copper you would know that it is a great conductor of heat, Blackpipe is much better as a temp spacer.

    Thomas

  13. #13
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    Kind of off-topic, but would a steel mailbox make a good coal forge?
    "Be Thou my battle-shield, sword for the fight
    Be Thou my dignity, Thou my delight,
    Thou my soul's shelter, Thou my high tower:
    Raise thou me heavenward, O Power of my power."

    - Ancient 8th Century Irish Hymn

  14. #14
    It works! Only one burner needed! Just as I guessed, one mailbox heats up approx 12" and two of them together heats 30"(shown in picture below). I heated 30" of 1/2" thick rebar and 3/4" roundstock forged into a blade. It also heats 1" thick roundstock(pictured below).
    Using the kaowool was terrible though, the dust irritated my lungs and made my hands itch. My measurements were off, so I just stuffed it in the mailbox and pushed it against the walls the best I could to make the open space. It's about 3-4" worth of space in there. Next time I will just use inswool because it's one piece instead of layers and dos'nt give toxic dust like kaowool does.
    The two forges together take about 20 minutes for the heat to spread evenly to both areas. I have to do some repair work on the first forge because the steel got so hot that it melted the kaowool, so i'll need to put some kaoboard over it next time so it wont happen again. Once I get the doors working, I should be able to heat about 36". Here are the pics:







    Glen Mergnes

  15. #15
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    Excellent Glen!

    Looks like it's working for you just fine!

    Good work, and good luck,

    josh
    The smith also sitteth by the anvil,
    And fighteth with the heat of the furnace,
    And the noise of the hammer and the anvil is ever in his ears,
    And his eyes look still upon the pattern of the thing that he maketh.
    He setteth his mind to finish his work,
    And waiteth to polish it perfectly.

  16. #16
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    Glad to see that your idea is working out!
    Justin King

    just killing time until my next bad idea....

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