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Fire Brick Forge Misconception

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by DReicht, Nov 16, 2006.

  1. DReicht

    DReicht

    101
    Oct 26, 2006
    http://s86.photobucket.com/albums/k83/steven_sharpe/Forge/

    I had always thought that firebricks will crack unless protected, by the extreme heat of the forge? How do these bricks survive without any protective coating? I'm assuming that he's using hard firebricks, but are they still resistant enough?

    And where can you find Fire clay, I couldn't find any at Ellis and google just gives me info about it.
     
  2. Justin.Mercier

    Justin.Mercier

    Oct 21, 2006
    there are many different types of fire brick. The typical hard yellow grainy stuff you pick up at the hardware store is firebrick made for fireplaces, not at all a refractory firebrick.

    Different firebrick is rated for different temperatures. Soft firebrick, and a lot of hte hard firebrick is rated for upwards of 3000 F

    That being said, the forge in that picture is not your typical propane forge made from firebrick, tha'ts a charcoal/coal burning bottom air-fed forge which functions entierly different
     
  3. DReicht

    DReicht

    101
    Oct 26, 2006
    Yeah I realize the different, I'm not a total blank when it comes to forges.
     
  4. DReicht

    DReicht

    101
    Oct 26, 2006
    Also how do you protect the tuyere from the heat of the forge? He said fireclay but souldn't that just prevent scorching and not heating? Or does the constant flow of air keep it cool on the inside?
     
  5. Don Hanson III

    Don Hanson III KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 3, 2002
    The hard fireplace brick will take longer to heat up and they absorb heat, where as the soft kiln bricks will heat quick and reflect heat back into the forge. They will all crack and should be held together with wire, sheet metal, etc. No need to protect the brick with clay but Satanite will work well if you do want to coat it.
     
  6. DReicht

    DReicht

    101
    Oct 26, 2006
    Adobe mortar would be just as acceptable right? And what are those long firebricks?
     
  7. DReicht

    DReicht

    101
    Oct 26, 2006
    Why build a forge of firebrick if it will just one day break? Will the mortar serve to hold it together? It seems sort of counter productive.
     
  8. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment Knifemaker / Craftsman / Service Provider

    Jan 12, 2005
    Because they're cheap as hell and easy to make. If you want a more durable forge, build one.

    Maybe I'm just reading your posts the wrong way, friend, but your wording tends to sound a pinch antagonistic. Hopefully, I'm just reading you wrong!
     
  9. DReicht

    DReicht

    101
    Oct 26, 2006
    I'm sorry :-\ I didn't mean to come off antagonistic, honestly I can't afford to come off antagonistic :). I've just been writing my posts seconds before I go out the door so I'm just being straight foward, as of now lol.

    If I took 2300-2500 degree rated firebricks and Covered them in a layer of adobe and then a coat of ITC 100, would they be permanent?
     
  10. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment Knifemaker / Craftsman / Service Provider

    Jan 12, 2005
    They won't be permanent, but if you even just wire them up pretty well they can last a while... my first one lasted for a few months of occasional weekend use. If you're planning on using it for more than that, make yourself a quick forge out of a coffee can and some Inswool.

    I've never tried to coat a firebrick, but I can't see why you wouldn't try -- they sure are cheap enough! I think I'd try a layer of Satanite first, to give the ITC-100 a more solid surface to stick to. I think I've got some of all of this stuff around... maybe I'll make one tomorrow and report back.

    Good to hear I was reading you wrong, btw... I have a horrible habit of coming off the wrong way, so I try to ask before I jump!
     
  11. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment Knifemaker / Craftsman / Service Provider

    Jan 12, 2005
    Well, I grabbed one of my 'falling apart' firebricks and glued it back together while lining the inside of it with Satanite just a few moments ago... the brick is now a lot heavier, and currently sitting in the oven drying. We'll see if this makes any difference. My guess is that I'm merely trying to polish a turd, but what the heck -- why not, right?
     
  12. DReicht

    DReicht

    101
    Oct 26, 2006
    Thank you for trying that, because I figure that even if a brick is broken apart, the denser adobe (with ash) should keep it about even.
     
  13. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment Knifemaker / Craftsman / Service Provider

    Jan 12, 2005
    I'll say this much for it, it's a whole lot beefier now, with a bunch of Satanite in and on it. How it holds up to the stresses of heat, we'll see in a bit.
     
  14. DReicht

    DReicht

    101
    Oct 26, 2006
    Thanks for all the help, jeez. See what I want is a charcoal forge thats gonna last, I don't want to have to buy new firebricks in two-three months which is why I thought of putting a layer of satanite/adobe and than ITC. ITC would serve as being reflective, as would the adobe to some degree, but the adobe/satanite would also be highly absorptive saving the firebricks from most the heat.

    At that point though, there is no real purpose to the bricks other than a shell? Which means I could use some 99 cent 2300-2500 rated firebricks right?
     
  15. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment Knifemaker / Craftsman / Service Provider

    Jan 12, 2005
    Yikes! That's MUCH different!

    If it were up to me, I'd order a smear of castable refractory (Darren Ellis sells it), make a form the shape you're looking for (at least for the lower portion, or even the whole thing, possibly in stages?) and THAT would handle quite a bit of abuse.

    Assuming I actually get my butt rolling, my vertical propane forge (a la Don Fogg) will have a cast refractory lining.
     
  16. DReicht

    DReicht

    101
    Oct 26, 2006
    I think I'm going to try the twin oaks forge for my first forge using the 2300-2500 degree firebricks as a base. If I keep up bladesmithing, I'll look at a nicer charcoal or even propane forge.

    Thanks for the help guys :)

    I'm just sorta worried the twin oaks forge may collapse into the fire after too much use, and crumple around the rebar.

    Also doesn't ash clog up in the twin oaks?
     
  17. DReicht

    DReicht

    101
    Oct 26, 2006
    So Many Different Ideas!!!

    BTW its a knife/casting forge.

    And I'll draw up a formal plan for tommorow.

    I'm really just afraid of blowing myself up sorry for all the questions :)
     
  18. DReicht

    DReicht

    101
    Oct 26, 2006
    Is it ok to have the charcoal sit on a grate of rebar or steel in order to allow ash to fall through?
     
  19. AwP

    AwP

    408
    Apr 13, 2004
    That should be fine, but charcoal ash (assuming natural lump charcoal and not briquettes) or wood ash actually doesn't hurt anything in the forge and actually makes good forge lining all by itself, one that won't break either since it's hard to break powder. don't worry about blowing yourself up, that won't happen with a charcoal forge.
     

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