Unless someone shows me how to use it
the stud gun is a pretty harsh way to shrink. I have a shrinking tip for mine and it really is for something that you want to simply stop it from oil caning so you can slather it with bondo.
The tip is spring loaded, a HEAVY spring. When you push it on the surface with a stud in it, this spring is mashing it against the metal as you meet the ground ring that is around the tip against the metal and then you pull the trigger to make your direct short welding the stud to the surface. So when you use the shrinking tip you are MASHING this tip into the surface, so think about this now, you have a small tip MASHED into the metal right where you are going to heat it up......you see where this is going? The tip goes INTO the softened metal and you end up with a dent.
It works like a charm IF you need some quick shrinking but it is no "tin smith" tool. Again, I sure as heck am wide open for someone to show me I am wrong so I can learn another trick. I know when I was working for a guy and pulled out my stud gun he showed me how to use it as I had been using it all wrong for a few years.
Here is a video of yours truly using the shrinker it's a horrible video with me dropping the shrinking tip but it will get my point across.
Here is one using the stud welder properly.
All you need is a tap on the button to weld it, just a tap like you do on your computer keyboard. You don't burn the thing in like I did before I was taught how to properly do it. In the video you will see how I weld a couple on and give it a simple wiggle and it falls right off. Then you will see me pulling with the slide hammer on one and I can give it a heck of a whack pulling on the metal pretty good, then a little wiggle and it falls right off. You do NOT need to burn it in so you have to cut it off with a pair of wire cutters for goodness sakes. But that is how I was using it not knowing any better until my boss showed me.