White out for canister damascus?

[Tom Lewis]

Although I have made lots of patternwelded Damascus I have never made canister Damascus.
I will probably try to make some in the future.
I have noticed watching "Forged in the Fire" that when the contestants are required to make canister Damascus, some put white out inside the can and some don't.
I understand the purpose of the white out is to be able to make it easier to get the can off after the billet is welded up.
But in watching the contestants, the white out doesn't seem to help any.
So my question is for those of you who have actual experience in this area, does white out really make it easier to get the can off the billet.

 

[kuraki]

In my limited experience doing it both with and without it depends on how far you plan to draw before removing the can. If you just set the welds and then remove the can, it's not terribly helpful, the scale in the can keeps it from welding to the billet to a certain extent. If you're drawing it out 3-4x before removing the can, it's maybe helpful. Whether you're doing mostly press or mostly power hammer might make a difference too.

I have no intent to use it in the future myself. Even if I had a canister completely weld tight, I would rather cut the ends off in the chop saw and grind the can off with a snagging wheel on my big angle grinder than chisel it off. If it doesn't just pop off with the chisel, I say hell with it and grind.

 

[Stacy E. Apelt - Bladesmith]

There are a couple ways to keep the canister from welding to the billet, but in many cases, as pointed out by kuraki, it isn't necessary.

On FIF, the damascus showing on the sides is not often a requirement. That means it is an advantage for the canister to weld to the billet. It assures a smooth and non-delaminated side. The hardened edge will be exposed in grinding the bevels. On blades where the side pattern is going to be seen, the canister can be ground off after welding and basic drawing out. This is often just about as fast as trying to chisel it off by hand.

In cases where you want to make the billet, remove it, and draw or pattern it further, the canister can be painted with any oxide paint. White out has titanium di-oxide in it .... that is why it is bright white. Any primer type paint would also work. You could spray it with titanium white Krylon paint and get the same effect. You could even make your own coating with titanium dioxide powder and some sort of evaporating carrier. I think water and gum tragacanth would work fine.

However, the addition of particles of the titanium, which will not weld to the billet, coming off the sides and getting in the billet during welding could risk a delam or shunt showing up. A little time on the grinder is a better choice.

Another method used is lining the canister with strips of stainless steel HT foil.

I sent some stainless steel canister material to Indian George many years back for him to experiment with, but never heard back how it did in releasing the billets. I will have to do that experiment myself one day and see how it goes.