I was making some exhaust pipes the other weekend for Firefly's 34 pickup and thought I would share some of the tricks I have been using to make it go a little faster. The first one is to make a carboard pattern that matches the bends that you are using. You can then use this as a pattern in the car to decide how much of the bend you need. When it is the right angle, fold the pattern where you want to make the cut. Then take the folded pattern and lay it on top of your u-bend and mark it. This also has the advantage that your cuts are square across the radius of the bend. Once you have the bend cut and sanded for a perfect fit, the next problem is how to hold it in place while you weld it. I have tried a few different ways, but the easiest and quickest I have found is just to use masking tape! Clean any oil off the pipe, and tape the join tightly with masking tape. When you go around a few times, it ends up fairly rigid and the pipes are well aligned. Take it over to the vise and cut a short section of masking tape out for a tack weld. Then tack it together. The tape gets a bit hot, but still holds together. Then flip it over and repeat on the other side of the join. When both sides are tacked, you can remove the tape and clean off the adhesive residue. Heres another example, showing how you can use witness marks on the joint to make sure that it didn't move while you were taping it up. In this case, the bend was more complex and I couldn't support the joint in the vise while welding it. The tape was still tight enough to hold the two pieces together to weld together though, and it came out fine. Heres the finished pipe, ready to fit.