You can fix dents at home if you have the right tools. You'll need an oxy acetelyne torch, an air compressor WITH regulator & clamp on air chuck and a couple of expandable pipe plugs ( one gets a schrader valve )
Here's the expandable plugs I used. I removed the bolt from one and replaced it with a schrader valve. A belt sander makes quick work of fitting the plug to the pipe diameter.
Hook up the clamp on air chuck, set the regulator at 10 psi ( you can go a little higher but I never go over 15 psi ) and get the torch.
Now move the flame in a circular motion so you do NOT sit in one area too long. You want to get the pipe cherry red, almost melting, as the air pressure pushes out the dent. I highly recommend using the correct dark glasses so you can "read" the cherry red pipe.
Here's the finished product
Longer, deeper dents will take multiple heat cycles. Really nasty dents may need to be drilled ( 3/16" or 1/4" ) on the far side so a punch or rod can be used from the other side to push it out after heating it cherry red. ( with out air pressure)
You will need to weld the hole shut before going back to the air pressure / torch method
Here's some more dents I removed
Oh, sometimes when you are heating an area to repair it, you find some "mickey mouse" earlier repairs ( like low temp brazing that melts instantly with a torch ) and you'll have your hands full with multiple repairs. ( right pipe )
