My stock exhaust manifold is cracked right where the two pipes fuse into one, I can't see the hole crack since it is still on the car. The two parts is still close to each other. I have access to a 250 amp CO2 welder, and know how to use it, but I am unsure if it will just crack right next to the welding.
So should I weld it or should I buy a new stainless manifold? Since the new manifold should be shipped to Denmark it will be around 220$.
Use the cracked manifold as an excuse to buy a header. It'll breathe better than the old stock cast iron manifold, plus it weighs less and looks cooler. I've been running an Ebay chrome header for over a year now. It was a nice, cheap mod that probably paid for itself in the first few thousand miles I drove (gas savings).
The design of the original manifold means it'll just crack again if you weld it up.
I agree with not welding and replacing it. Also make certain the condition of your motor mounts and transmission mount as they can be a cause of manifolds cracking due to the design of the exhaust system.
I have brought a new one now. My motor mounts looks fine, I checked them very recent, but I don't know about my transmission mount. Would it be an idea to put a flex into the pipe downstream of the manifold.