OK, gotcha. I believe hellgap intends to weld on a tang of cheaper material than the blade. You'll notice that since the blade is stainless steel, folks are advising against it.
With carbons steels it would probably work better, they are just easier to weld (Disclaimer: I haven't welded anythign since HS shop class so don't think I'm an expert

)
Bill Moran used to forge-weld mild steel tangs to his blades; Wayne Goddard describes silver brazing as the strongest type of joint for this purpose.
Personally, I haven't learned to do this because I don't see much point to it for what I do (stock removal). I start with flat stock the full size of the knife, even if it's going to be a stick tang. Yes, there's waste involved. But there's no joint to ever fail or corrode.
The cost of the steel itself is way overblown by a lot of folks. High-grade CPM154 is around $60 for a 3' bar of 3/16 x 1 1/2. That sounds like a lot, but it breaks down to $15 for a nine-inch piece, enough to make a typical full tang hunter. If you don't want to buy a whole bar, you may be able to find a knifemaker here who'll sell you a small piece for a nominal fee plus shipping.
Fifteen bucks is lunch for two, not a big investment
