|Photo From Here|
It's always a pain in the ass to try and tack pipes together. If you TIG or gas weld, that requires two hands. Doesn't leave much left over to hold things in position on the bike. Even if you try to tack the pieces together on the bench or in the vise, it's still never easy due to all the curved shapes. I usually start with the piece of tube that has the clamping flange on it. Put the gasket in the exhaust port snug it up and start working my way back. Get one piece where I want it, fit the next piece to it, put a couple of witness marks on it, take it off, tack it together and repeat. Hopefully, it's in the right spot after tacking and I can keep going. If not, grind off the tack, make a little adjustment and repeat the process. Time consuming. I can see these clamps being real useful. Just wish I would have thought of it.