I usually tack weld my exhausts with a flux cored welder and man i know what ur talking about with the holes and just a sloppy fusion. U can see the porosity ofth weld when you weld them up with tig afterwards but it is very convenient to hold the pipe in place and tack it together very quickly.
The Pennsylvania State University
Studying Industrial Engineering
Everlast PowerPro 205
Everlast I-Mig 200
Milwaukee 14" Dry Cut Saw
Craftsman 6"x48" Belt Sander with 9" Disc Sander