I weld all my blades (up to 1/2") using the Ideal welder on my Powermatic 87. When I first began I expected problems, but I've gotten good welds from the beginning. I did have to adjust the jaws to get good alignment, but that was all that was required. Carbon steel, bimetallic, even carbide has worked out fine, hardly ever had a blade break on me,just followed the instructions. I am primarily a woodworker, do a lot of resawing, have a PM 81 as well, but also cut steel, alum & brass.
Also, I've done practice welds on short straight pieces with no problems. I find it hard to believe that the blade has to be a loop, all the critical business is going on between the jaws.
And then I don't get why people say you can't weld carbide blade on these things. The body of carbide blades can't be that much different than bi-metallics, the carbide teeth are just going along fro the ride.