Crucible / woodz steel : make it using a propane furnace ?

Discussion in 'Furnaces and their construction' started by metallab, Sep 17, 2023.

  1. metallab

    metallab Silver

    I found some Youtube videos on this how to make it.These show usually a guy putting bearing balls in a standard clay / graphite crucible. Then they put some graphite powder on it, some flux and some glass shards as extra flux. What amazed me that they don't pour it out, but let it freeze in the crucible and sometimes even seal the crucible before melting. After opening the cooled crucible they succeed to release the frozen steel bum without damaging the crucible.
    Why don't they just pour it into a blank for e.g. a knife ? Forging a bum shaped piece of steel is much more work than a knife blank.
    I want to try it myself.
  2. I think the process of making Damascus steel with it's layers or ferric carbide and lower carbon steel requires lots of forging anyway. If you made a low silicon cast iron, you'd end up with white iron instead of grey iron which is pretty much what wootz is. Bearing steel is 52100 alloy so it's high carbon and high chrome, they could have just used the inner or outer ring of a parallel roller bearing, slit and forged flat and ended up with a better more consistent result.
  3. I watched this video:

    where the person was able to melt steel into iron and I compare it to the time taken and the radiant heat visible at the 6:26 mark in this 1949 crucible steel foundry

    and I have my doubts as to whether he actually got things hot enough to melt, especially as the whole charge was sitting on a steel rebar grate that didn't melt. You watch people running a cupola or reducing iron mineral sand ore to a lump of Tamahagne steel and they run for a hours and require added carbon/coke to get a result where the guy with the ball bearings makes it look trivially easy by comparison while burning something that looks like brown coal or peat pellets.
    Last edited: Sep 17, 2023
  4. metallab

    metallab Silver

    Amazing those 1949 videos. At the end I saw a guy operating a real optical pyrometer, probably a Hartmann & Braun one. But the guys did not use any PPE, handling liquid steel or forging without gloves and even with bare face ... How many accidents did take place ?
  5. 4cylndrfury

    4cylndrfury Copper

    Its entirely possible that he was using some form of denser coal, he doesnt really show what the fuel actually is. And while there was indeed a rebar grate, theres also a plinth that isnt easy to see (in other vids you can see its just a hunk of firebrick). You also have to remember that the air is blowing up from under it - the heat was concentrated above in the furnace, not below it at the grate. The incoming air charge would help keep the steel cooler than the fire above. Think about handcranked forges where the whole table is steel and only a small area of actual fire is active at any given time. Theyre in the same boat.

    Coal is also very insulative to the outside environment - the heat is trapped in the cavity within the coal. Between the coal's insulation and that of the soft firebrick, those few cubic feet would get insanely hot. You can make bronze with charcoal in a hole in the ground, zero insulation required. Im subscribed to and watch that FZ channel frequently because bladesmithing is super interesting to me and wootz feels like blackmagic voodoo. His videos are certainly edited to make the process seem easy, but given the sheer quantity of videos where he features the wootz process on camera, either his grift game is world class (in as much as it is super consistent), or he really just does this a lot and has the process down pretty solid.
  6. Jammer

    Jammer Silver Banner Member

    PBS NOVA 2017 Secrets of the Viking Sword - YouTube

    This is about the best explanation of a crucible steel that turned up in Viking swords. Ric Furrer used to be on some blacksmith forums but I think the self proclaimed "experts" drove him away like they do on so many forums.

    The Secrets of Wootz Damascus Steel - YouTube

    Then true Wootz Damascus explained, another great video. With real experts.

    The steel doesn't get hot enough to pour, it just fuses together in a mass. Getting it to fuse is just the first step. Some videos show putting the block through several heat cycle to distribute the carbons. Then careful hammering out into a bar, then on into a blade. I better stop, I'm sounding like an "expert". I've just read a lot about it and watched several videos.

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