Canister Treatment

B

bc1235

Joined
May 6, 2020
Messages
7
Pretty much all my blade making observation has been Forged In Fire. Many of the challenges require canisters and about 90% of the competitors have difficulty getting the canister off. I see most of competitors use whiteout, most not letting it dry before loading it up (makes you wonder if these guys watch the show at all, this is mentioned often). I'm curious if doing something radical like this would work better than whiteout if your intintion is to peal off the canister. For that matter has anyone ever even tried this? Before putting anything in the canister put it in the forge to get it cherry red then quenching it in water to make it brittle. Then load it up with the hardenable material (No Whiteout). First question is will any cracks developed in the canister be big enough or deep enough to allow oxygen into the canister? Next question: will this technique even work? Will the canister will be brittle enough to break apart after the initial forge weld? Other thought: what would happen if instead of the above technique the canister is filled as usual Without Whiteout, then after doing the initial forge weld the canister is quenched in water to make the can brittle. Will that rapid heat change transfer into the inside steel ruining its integrity?
 
The can is usually mild steel so I don't think you can harden it to make it brittle.
 
Over the last several months I have made a lot of canister Damascus. Hoss is right. Don't worry about the can. It is a waste of time trying to take it off. Just forge the canister down, grind to shape and the can will be gone.
ojJ47BI.jpg

this blade was done with motorcycle chain and 1095 powder. I did not use whiteout and did not try to take the can off. By the time you are through drawing the billet out the can will be paper thin and will grind off when you grind the blade.
 
White-out creates more problems than it cures. You can fold a piece of stainless HT foil and line the canister, but that isn't foolproof either.
Best solution is to leave the canister on and work the billet down to a thickness where you just grind off the remnant. A lot goes away as scale during the heats. In this way the canister protects your billet until it is a bar ready for final shaping. Another plus is you totally eliminate the possibility of opening up the canister before it is solidly welded.

If the canister walls are .125" (3mm) when it starts as a 2" tube, it will be about .01" (.25mm) by the time the billet is drawn down to a usable thickness and length. This usually grinds off in the clean-up grinding or surface grinding. A quick dip in the FC tank will show any of the jacket remaining that needs more grinding removal.
 
Thank you all for your replies. The unlikely possibility of the canister hardening explains why I've never seen anyone doing it.
Interestingly the other all your postes support what I've seen the best contestants use, don't bother removing it, just grind it off.
Again thank you all.
 
Stacy made two observations that I would emphasize.
1. "A lot of the canister goes away as scale during the heats." This is so true. It is a lot better to loose the canister to scale than to lose the billet to scale. The canister protects the billet from scale. So leave it on.
2. The billet may not be completely welded after the first heat. But if the canister is left on subsequent heats have a excellent chance of completely welding the billet. So leave the canister on.
 
I never thought about the final thickness. More and more it makes me wonder why people spend so much time trying to peel the can off.
 
Tom Lewis said:
Over the last several months I have made a lot of canister Damascus. Hoss is right. Don't worry about the can. It is a waste of time trying to take it off. Just forge the canister down, grind to shape and the can will be gone.
ojJ47BI.jpg

this blade was done with motorcycle chain and 1095 powder. I did not use whiteout and did not try to take the can off. By the time you are through drawing the billet out the can will be paper thin and will grind off when you grind the blade.
Click to expand...
 
That is really a beautiful blade. I may take up bladesmithing in my next life. I think if I take up one more hobby now my wife will have me committed then the only hobby I have is basket weaving :)
 
bc1235, I know how you feel. I have had lots of hobbies. Knifemaking is the only hobby I have had that paid for it's self.
 
I would never waste my time trying to remove it. As Stacy said a 2” can reduced to 1/4” will reduce the wall thickness to .0156. That’s not taking into account stretching the can out length wise or and loss from scale.
 
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