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.
I like your masking tape joint, real eazy and real cheap. I have used hose clamps with 3/8" holes drilled in them to tack the joint through. It works OK but the tape Idea might just work better, I'll definitely give it a try on the next set of pipes I build. Thanx Jaysin
good tips..and ill take it a tad further...make a master set of bend template and photocopy it...Id end up losing mine about 50 times while i was fabbing
I hear ya - I made a template for a tighter bend as well but lost that before I even started ! The template is made of cardboard, so probably easier to trace a couple of spares rather than photo-copy them.
Great job!! Thanks for taking the time to post it. I recently finished fabing the exhaust for my car and truck. The template trick sounds like a good idea, I'll definitely have to keep that in mind for next time. I used a hose clamp snugged around the pipe, and traced around it with a sharpie marker to make my cut lines. I've also had good luck by using a few magnetic traingles to help hold the pipes in position for welding.
I do it the same way, I've tried the hoseclip with a hole in it as well but the tape works much better. I find the tape leaves glue behind so after tacking i clean the joint.
thats how I've been doing it for close to 33 years.....it's not hard, just take your time and make the joints as tight as you can. Some times I get them so tight my old ass eyes can't see them to TIG weld them. If you get them that tight no filler rod is needed you can "fuse" them together, that makes a very tiny bead. I always try for that fit.
Simon, these are some fascinating tips that you provided on doing a custom exhaust fabrication. You know, this is something that I am preparing to do for work. Well, since a client of mine wanted me to do for upcoming week. http://www.genie-exhaust.com.au
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