Melted blade.......

P

paintfool

Joined
Sep 7, 2004
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trying to heat treat a large tanto with an o/a torch and it got too hot on the edge for just one second and the damn thing melted away the thinest part of the edge about 1/4" up into the blade.......man what a piss off....... and the worst part is it's not near the tip, it was right near the plunge line.

live and learn I guess.....what a stupid mistake, I should have known better.
Steve. :mad: :(
 
I guess the other way to look at it is that it's better to have melted it and know than to put a poorly HT'd blade out there from overheating in spots.
 
Sorry to hear that. But not stupid enough. I was forging my first knife last year, in a japanese type charcoal forge. The phone rang and I answered. When conversation was over the blade was not there anymore. I searched everywhere then I remembered that I left it in the coal with blower working. One day later I had to scrape the metal from the forge floor :D :)
 
I paused for just a second to adjust my grip to get ready to quench and I guess that was just long enough to ruin the whole thing.....
and I agree that next time I'll know better than to run it that hot.
Steve aka "investing in a forge" :p
 
Even a forge can be prone to hot spots, and has to be considered. If you go that route consider a pipe-in-the-forge and knife inside pipe to evenly distribute the heat. Vertical forges tend to have more even heating.
 
what kind of flame should I be running with it(torch) to avoid this? should I make a soft flame and just take it slow, would that even get hot enough?
I should have asked a few more questions and read a bit more before trying.
Steve
 
I have a hand held propane burner. Even with butane tank attached it serves well. With oxy/acetylene heat treating is harder to manage. Even with butane burner it is hard to heat even, the Ox/Act torch is good to solder/cut but not HT.

I suggest try to build a propane or coal forge with your Oxy/Acetylene torch :D .
 
Steve, a rosebud tip would serve better than a welding tip, IMO. Others will sound off here and methods will differ. Some use y-tips.
 
I use a # 4 ( I think) tip and a rosebud. Best advice I can give is to never touch the lower 1/8" with the flame. Let the heat build up and dont rush it. Remember that even in a forge you will need some soak time. I try to have a small amount of soak time when using the O/A torch. Its more about getting the heat even than a traditional soak time. My terms here are very loose. fitzo may can sum up what I am meaning.
 
Steve, I use a O/A torch all the time also and I always make sure that I have a feathered flame. When welding one uses a rather short hot flame and when heating a blade you will be better off if the flame is longer and feathered out. That way if you get to close to the blade it won't melt it. Your futher away from the blade with a longer / feathered flame so the chance of getting to close and burning the thin edge isn't quite as bad.
Ron
 
galadduin said:
, the Ox/Act torch is good to solder/cut but not HT.
:D .
Click to expand...

I wouldn't say that..
but I would say the other way around.. :)

I use my cutting tip I have for a long time I just back off the O2
but I've been doing this for a long time too. so practice practice practice
and go slow kind of fast you'll see what I mean once you get it..

bummer burning it up,, but that is a lesen learned well :)
 
I think I'll have to use this weekend to practice on some scrap and see if I can get the hang of it before the next blade gets any flame.

It does suck and I was pretty po'd but I'll use all of your guys' advice and hopefully get it down.

One more stupid question for ya's! :p
Does the temp of the quench really matter other than fear of cracking the blade? can I just use room temp oil and get the same results? the steel is O1 btw.

a "fool proof" recipe for O1 would be fantastic if anyone has one. (I tried to search for posts about HT'ing O1 but every single time I do, no matter how I phrase it I get a page cannot be displayed)

Thanks everyone, Steve.
 
Steve, heating the quench oil lowers it's viscosity. This reduces the tendency to make little bubbles cling which causes slower quenching.
 
i have had good luck HT'ing O1 with a rosebud oxy/acel torch. I just heat it real slow. About 2 minutes to get dull orange, let it soak for a couple minutes. Have a magnet and keep the blade cool enough to stay magnetic for a couple minutes, Then heat up till the blade looses magnatism. Quickly dip and swirl in hot tranny oil till its just as warm as oil. Stick in oven (clean) at 375 for an hour. Take out and let air cool. Put back in oven at 375 for another hour and let air cool. Works for me.







0
 
you need to heat the oil to around 140 degrees. It can be lower. What kind of quench tank do you have? I am planning on making a nice stand that has a modified side burner from a grill under it to get my oil to temperature.
 
well it was just going to be a mild steel pan with a burner under it, nothing serious, using a thermometer to check for the right temp.
but as you can tell from above I never really made it to the quench :D
I think the biggest mistake was we were using a pipe with a hole cut to try and keep some of the heat on the blade, because it was the bigger blade, and it was really hard to tell what was going on inside it.
I just need to take my time, and make sure not to over heat it, I think I was on the right track but just made a mistake. :footinmou
Steve
 
I use a steel coffee can, the bigger one. The other day I needed a deeper one for a machete, so I epoxyed two cans togeather. Just cut the bottom out of the top can. Worked good! Let the oil cool off and snap on the plastic lid to store. Had a time getting the 14" blade to heat evenly with the rosebud, but seems OK. But as many knifes as I have been making, I decided to order an Evenheat knife oven the other day. The 18"deep model.
GARY
 
yeah, I'm trying to get a grant from a local office, if I do I'll be getting an evenheat for sure, along with a lot of other goodies ;)

I'm trying it again tonight with some scraps, if I get those to work out ok, then I'm doing another smaller blade.
wish me luck! I'll need it....
Steve
 
One other thing about the torch is to not hold it at an angle. Keep the tip square with the metal. And carry your heat through out " As soon as it shows slight color move it slowly back and forth" You probably knew this but.... Hey thats my .0000002 cents worth. :D
 
paintfool said:
a "fool proof" recipe for O1 would be fantastic if anyone has one. (I tried to search for posts about HT'ing O1 but every single time I do, no matter how I phrase it I get a page cannot be displayed)
Click to expand...

I ran into same problem (with broken forum search) a while ago, maybe you will find this useful (O1 listed among other steels): http://www.knives.com/heatreat.html
 
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