I picked up this set of beat-up pipes for my current project. They were typical of a 30 year old part and were rife with dents and creases. Ive heard a lot of talk of guys putting water in pipes and freezing them to push dents out. I promise you this will bulge your pipe in ways you don’t want. I decided to pull the dents out using a trick I learned working at an auto body shop years ago.
At the body shop we had this slick little spot welding gun that would weld studs to the sheet metal and you would pull the dents out with a slide hammer. I have neither of those, But I did have some old spokes, a torch and welder to work with.
After welding the spokes on I heated the area cherry red and slowly pulled to working as I went. Sometimes I had to go back and reposition the studs after I pulled it all out to get the last bit. I finally ground off all the stud mount welds to finish the job. These pipes woulnt be perfect after this but much better than before and they are getting painted soon.