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Help! I killed my forge with Borax!

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Jesse Smith, Jun 6, 2015.

  1. Jesse Smith

    Jesse Smith

    162
    Dec 2, 2013
    My forge is a 30 lb horizontal propane tank with 2" of Kaowool covered in Satanite. I tried forge welding for the first time today. Just tried practicing with a couple pieces of re-bar, and 20 Mule Team Borax for flux. I know Borax will eat away at the Satanite, but isn't it something that happens over time? My bladesmith friend just runs bare Satanite in his forge and I think he said he relines it every couple years. Most of his blades are Damascus, so he does a lot of welding. But my first attempt completely ate the lining out of the bottom of my forge. :mad:

    What gives? Is this normal for it to destroy it the first time it comes in contact with the Satanite?
     
  2. elementfe

    elementfe

    May 3, 2008
    The floor of my forge is more than ten years and a LOT of forge welding old, and I'm still waiting for it to wear out....but it hasn't begun to.
    Hard firebrick, like the kind you use in a wood stove.
     
  3. Fred.Rowe

    Fred.Rowe Dealer / Materials Provider Dealer / Materials Provider

    May 2, 2004
    Switch to Kerosene [hydrocarbon solvent] it will not eat the forge lining and the temperatures needed are 100 degrees less than with Borax.

    Its cleaner all around, breathing air borne borax is hard on your lungs.

    P. M. me if you want more information.


    Fred
     
  4. Russ Andrews

    Russ Andrews Knifemaker Knifemaker / Craftsman / Service Provider

    Nov 27, 2002
    Most of us start out with borax.....and eventually try Kerosene......then after thinking about it for
    a time, we try dry welding...and it's like an epiphany.....WTF.....clean steel...an O2 free atmosphere
    and enough heat...and the steel wants to weld..!...It WANTS to weld..!

    Seems like we make welding a whole lot more complicated than it needs to be...!!
     
  5. Would you mind sharing the process you use to do this? Do you just grind clean surfaces to start and brush frequently?

    Hell, I also wouldn't mind hearing how to use kerosene...
     
  6. SinePari

    SinePari

    906
    Oct 24, 2013
    The method is referred to as: Dry Welding AKA Bare-Back*

    A good link regarding the process...http://www.americanbladesmith.com/ipboard/index.php?/topic/1361-dry-forge-welding-damascus-without-flux-or-kerosene-topic-for-december-2013/

    An even better link comparing and contrasting flux welding and dry/bareback welding

    http://www.cashenblades.com/dryweld.html
     
  7. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    Some details about your damascus technique and a few photos would help.

    You say the forge bottom is eaten away? Are you sure the satanite is gone...or just covered with a layer of borax glass. It can look pretty ugly.

    How much borax are you using? It only needs to lightly coat the billet. I sprinkle the borax on over a pan and shake off the extra before putting the billet back in the forge.
     
  8. Steve Beckwith

    Steve Beckwith

    254
    May 29, 2004
    Maybe I shouldn't weigh in here because I really don't know anything about forge welding but I do know something about the corrosive effects of glass on refractories as I was an off hand glassblower for 14 years. I always kept about an inch of silica sand on the bottom of my glory hole (reheating furnace) to catch crack off glass that would thermal shock and pop off in the furnace. The sand would absorb the glass but its melting temperature was somewhere around 3000 degrees. I would regularly go through the sand and pick out glass clumps and smooth the sand and I never replaced the frax liner in the 14 years that I used it.
     
  9. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    Another trick is to get a piece of ceramic kiln shelf tile for the bottom of the forge. i have been told that giving it a slip coat of bubble alumina refractory will make it even more durable. The caveat is that the tile will eventually crack.
     
  10. Jesse Smith

    Jesse Smith

    162
    Dec 2, 2013
    I wasn't making damascus. This was the first time I tried forge welding, and I was just trying to join a couple of pieces of re-bar together to learn how.

    Here's a picture I took of the damage. The damage was all to the top 1" layer of Kaowool, except for one spot about the size of a silver dollar, which had erroded almost all the way down to the forge body. I After reading the comments in this thread about barely sprinkling a little Borax on the metal, I think I used way too much. I used teaspoon and just dumped a whole scoop on each peice, thinking that it burned off in the forge and not knowing better.
    [​IMG]

    So, my plan for the repairs are as follows. I cut the top 1" of Kaowool out of the bottom of the forge. This removed all the damaged area except the one hole that went all the way down. I patched that hole with a chunk of wool I removed...
    [​IMG]

    I coated the exposed Kaowool, and reinforced the edges with a layer of Satanite. I'll put a couple more layers in as they dry. Then I plan on putting a 1/2" of kitty litter in the channel I made (1/2" in the middle, less toward the edges because of the radius of the forge). Then I plan to lay in a row of firebrick that I have, on top of the kitty litter. The bricks will stick up about 1" above where the inside radius of the forge meets the sides of the bricks. Then I'll fill in the sides next to the bricks with more kitty litter.

    Here's a quick sketch of the plan...
    [​IMG]

    I didn't draw it in the sketch, but obviously the inside is covered in Satanite, including the inside the channel that the kitty litter and brick will be.
    Sound like a plan?
     
  11. Steve Beckwith

    Steve Beckwith

    254
    May 29, 2004
    Will cat litter take the heat?
     
  12. elementfe

    elementfe

    May 3, 2008
    IIRC, the soft firebrick is very vulnerable to borax. Some blacksmiths use crumbled brick for a disposable floor, like the sand mentioned above.
     
  13. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    Yes, the clay type litter is good for forge floors.




    Jesse - If you put a brick floor in, use hard firebrick ( get it at the lumber store) for a floor.
     
  14. Jesse Smith

    Jesse Smith

    162
    Dec 2, 2013
    Thanks Stacy. I stopped after work and picked up some hard fire brick. They only had it in 1.5" thick pieces, but I'm thinking that if they don't crack on me, that may work even better because it will allow me to put a much thicker layer of kitty litter under the brick for any runoff.

    I'll post pics when it's all finished (again).
     
  15. Fred.Rowe

    Fred.Rowe Dealer / Materials Provider Dealer / Materials Provider

    May 2, 2004
    Try the kerosene, you'll like it. cleaner, no forge destruction, lower temperatures.
     
  16. Jesse Smith

    Jesse Smith

    162
    Dec 2, 2013
    Back online! [​IMG]

    Coming up to temp...
    [​IMG]

    My bladesmith buddy, said the brick floor would be a cold spot, take forever for the bricks to heat up, take forever for the forge to cool down, etc. After using it I can see he was right. But, when I talked to him the repairs were already done and cured and the only thing left to do was dump in a layer of kitty litter and set the bricks in place. So we figured I might as well try it for a while. But I will probably go back to just a Satanite lining with some of the bubble-alumina stuff eventually, plus I'll try using kerosene to create a carbon flux layer, or no flux at all by adjusting the forge to a reducing atmosphere instead of an oxidizing atmosphere.

    Here's a pic at operating temp (somewhere around 2100° F.) That's a piece of Aldo's 1084 welded to a piece of re-bar.
    [​IMG]
     

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