Heat Treating Catatstrophe - Pics

Col Defender

Col Defender

Joined
Nov 11, 2011
Messages
1,398
Hi - will try not to make this too long.

I'm a beginner using 1084. This was my second attempt at heat treating and it turned out not so good. First time I did OK. I was told by one expert that I could heat treat 1084 in a campfire but when I tried that in my fire pit I could not get the blade even red hot.

So I improvised a little forge from a tiny one burner cast iron cook stove. Built a charcoal fire and used my shop vac with hose reversed to blow instead of suck. Worked great the first time but Sunday I ruined a couple of blades - obviously too hot.



Whether my fire was too hot, or I left the blades in too long I do not know. Really does not matter. Next time, should I try the campfire again, perhaps with hotter burning wood or with charcoal added, or should I use my little forge and just be more conservative/careful? Could I get enough heat without the shop vac? Use a blow tube? etc etc

Pic of my little forge - when I took the photo I was warming up Canola Oil in the ammo can which is why it was there just then.



Or is there a better way to treat 1084 that does not involve buying a little furnace? All part of trial and error learning I know. (Good news is I was doing 5 blades and 3 are OK.)

Thanks

Steve
 
Col Defender said:
Thanks - propane torch or cutting/welding torch?
Click to expand...

For small blades you can use Mapp, for large I use Oxyacetylene.

ETA: I am just a beginner too, I just heat them to non magnetic than quench. Than I temper in the kitchen oven.
 
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The experts will probably be along shortly to explain and I am far from knowledgeable about this. I have made a little "redneck forge" using a shop vac set up before and found the vac put out way too much air. Had to back the hose up a bit away from the hole to kinda "baffle" the air. As I said I could be completely wrong etc etc and have only done this playing around but I'd say if you could find a reliable way to regulate your air this could work. Good luck out there and have fun!
 
to me, and take this with a grain of salt as I am fairly new at this. It looks like you needed to be keeping an eye on it closer as it got way too hot. check for non magnetic as said in the sticky and so on. Im sure someone with more knowledge than myself will be along shortly. did you monitor the blades closely when doing this? I hold mine with tongs while heating in the forge and watch the color closely. also ht one at a time. no problems so far for me. hope this helps
 
Yeah - one at a time from now on for sure - moraldilemma666. And less air from the shop vac iwouldhurtafly.

And I have a follow up question for anyone...the knife on the right has a half circle about quarter sized that melted/burned away. I just reground the edge so that that "cutout" is gone and I now have a more slender blade. I could finish it up now and have a good looking knife but is that OK to do? Did the excess heat ruin the steel in some way that I cannot see?

And if I do this, should I reheat treat it or just finish it out?

Thanks so much!
 
Do a search for paint can forge or coffee can forge. The idea is you add insulation (ceramic blanket) to the inside of paint can and then coat the insulation with Satanite and ITC100. It's what I use with propane and it works great.
 
The biggest error with your system was the shop vac. It has far too much air blast. Put a PVC valve on the PVC pipe going to the forge and you can throttle it back as needed. A HT fire is smooth and even, not a blast furnace for melting steel.

Set the air flow valve at very low and stick a bar of steel in the coals. Slowly raise the air flow until the blade gets non-magnetic and do your HT at that setting.
 
The steel on the inside of the burnt part is probably ok, but you will have grain growth. You will need to run through a normalization (grain refinement) cycle before quenching.
Use a @ 2" pipe as a muffle in your forge. It makes it a lot easier to see the color of the steel as you heat it up and it makes it a lot easier to check the magnetism.
 
Col Defender said:
Hi - will try not to make this too long.

I'm a beginner using 1084. This was my second attempt at heat treating and it turned out not so good. First time I did OK. I was told by one expert that I could heat treat 1084 in a campfire but when I tried that in my fire pit I could not get the blade even red hot.

So I improvised a little forge from a tiny one burner cast iron cook stove. Built a charcoal fire and used my shop vac with hose reversed to blow instead of suck. Worked great the first time but Sunday I ruined a couple of blades - obviously too hot.



Whether my fire was too hot, or I left the blades in too long I do not know. Really does not matter. Next time, should I try the campfire again, perhaps with hotter burning wood or with charcoal added, or should I use my little forge and just be more conservative/careful? Could I get enough heat without the shop vac? Use a blow tube? etc etc

Pic of my little forge - when I took the photo I was warming up Canola Oil in the ammo can which is why it was there just then.



Or is there a better way to treat 1084 that does not involve buying a little furnace? All part of trial and error learning I know. (Good news is I was doing 5 blades and 3 are OK.)

Thanks

Steve
Click to expand...

Without seeing what you did it is a little hard to point out exactly where things went awry. During heat treating, a blade should be kept in a neutral atmosphere or a carburizing atmosphere. Otherwise no excess oxygen. Too much fuel causes an orange flame burn on the output of the forge, too much oxygen causes the blade to burn. It is OK to use the blast of air to run the forge heat up, but cut it off while the blade is in the forge. Keep the blade moving back and forth to reduce hotspots on the blade. Check the steel with a magnet to determine when it goes non magnetic, heat for a few seconds more (depends on how hot your forge is) then pull out and immediately quench. If you are trying to use color to determine temperature, do it in subdued light, inside or of an evening.
I realize this vague but hopefully it gets you better results.
Good luck!

Jim Arbuckle ABS JS
 
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