oxyacetlene heat treat/charcoal has natural flux?

E

elvenbladesmith07

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Jul 29, 2004
Messages
663
i was wondering if i could use an and oxyacetelene torch to heat treat. i would of course turn of the oxy and just use the accetelene because it will coat the blade black and that black stuff is carbon so i figure instead of losing carbon, i will gain carbon if anything. this is for my katana blade because i dont know how else i would heat treat it my forge is to small to get an even temp and im poor so i cant really have my blade shipped to a ht company.what do u guys think?
also i heard that the ashes of a carcoal forge will act as a flux during welding? so if i forge with a carcoal forge will my steel lose any carbon?
 
I'm not sure you can get even enough heat over such a large peice using heat from a single point like that. If you get a good rosebud tip for it and tune your flame right maybe, but I don't know. Haven't used a torch for a whole lot other than cutting so I don't know how it would work for that. I'd rather not have the heat concentrated at one point though.
If your going to forge it over coal, why not heat treat it that way? If it will get hot enough to forge it will be hot enough to HT with.

As far as carbon loss, I don't know a whole lot about it other than you will have to have enough meat on it before hardening to grind all the scale off. Obviously you have to do this to polish it, but I think decarb generally is no deeper than the scale. So try to be efficient with your heating to produce as little scale as possible, and don't over heat it anywhere and you should be alright.
 
Acetaline alone won't get it hot enough to do any good. Even with a rosebud I think you'll have a really hard time getting a katana up to temp. I've never tried torch hardening anything longer than about 8 inches and even that was really hard to keep the whole thing even.
 
ElvenB,

Stop. I would hope for you to go to www.use-enco.com and order the book 'Heat Treatment, Selection, And Application of Tool Steels' written by Bill Bryson. In addition to that read the write-up by our very own Mete found on Dan Gray's website. Search here on Dan Gray and you will find his link to that. You are going just a little too fast and, bless your heart, getting too many horses ahead of the cart.

RL
 
Everything rlinger said,plus....The amount of carburization/decarburization is a function of time and temperature.Coating the blade with carbon (lamp black) from the acetylene would do nothing except expose you to a whole lot of carcinogenic lamp black. You can learn how to build an inexpensive trench forge on some of the link sites,I believe.Depending on your amount of experience,sending the sword out for HT may be wisest.As rlinger said....study up on it first.
 
rlinger said:
ElvenB,

Stop. I would hope for you to go to www.use-enco.com and order the book 'Heat Treatment, Selection, And Application of Tool Steels' written by Bill Bryson. In addition to that read the write-up by our very own Mete found on Dan Gray's website. Search here on Dan Gray and you will find his link to that. You are going just a little too fast and, bless your heart, getting too many horses ahead of the cart.

RL
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i make swords quite often actually its just i useually had my grandpa ht the blade for me. now he is retired, since last year, i havent been able to do any swords or very large knifes because my forge is to small to get the whole blade into the coals and get an even heat. i was thinking about useing an oxyacetelne with less oxygen that acetelne and the passing the flame with a rosebud tip up and down the blade slowly. ive done this with a propane torch on small blades many times and i was just wondering if it would work on a bigger scale. i geuss i should have been more specific.
 
You can make a makeshift charcoal forge that's long enough pretty easily. You can dig a V shaped trench in the ground long enough for your blade, put a multi-holed pipe tuyere (like a washtub forge) along the bottom of the trench with your normal blower attached. Unless you live in a place where this isn't legal to do, in which case you'll need some sort of box up off the ground to hold your fire.
 
sound good to me awp. thanks for the help. id rather use that instead of using acetelene. its just my blade is curved to ill have to dig a deep pit to get the hole blade in there. i can wait to get that hardening forge going!
 
I wouldn't recommend using the acetylene torch for the sword blade. If I remember right, this was made of 1084? If made of 5160, L6, or 52100, you can heat treat a blade 10 miles long with a torch if you want. Just take a rosebud tip, and heat ONLY the bottom portion of the edge about 3/8 inch up from the edge to austenitizing temp, and move the torch along the edge heating the edge as you go. The spine of the blade will draw the heat out of the edge of the blade fast enough to convert it to martensite. When you get to the tip, quench the tip since it will be the least likely part to harden. I did a 28 inch L6 japenese style sword blade in this manner, hardened very well.
Simple steels don't harden by this method - I believe they need chrome to do it. Its been a long time since I was taught how to do that
Learned that trick from the great Howard Clark
Happy hammering
 
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