heating tip size for shrinking
 

on my 914s rear trunk it has the classic dip where people have pushed on it over the years closing the trunk. A PO filled the dip with about a 1/2 inch of filler! I stripped the trunk and removed all the filler. I hammered out the dent and it looks almost perfect but there is some oil canning going on from the steel being stretched. I took an autobody class and the instructor showed us how to shrink the metal for this situation with a torch. I bought a acetylene torch setup off craigslist but it doesn't have a heating tip so I need to buy one. It's a uniweld setup with a 71 weld handle. Looks like I can get a type 17 or 28 heating tip. The 28 comes in either a 15 or 30 tip size. The 17 has like 4 different tip sizes. Not sure if those are standard sizes or uniweld specific.

What size is best for heating up the steel for shrinking?

Thanks

with most palm size a small tip works very well .
how ever it all depends on the area that is oil caning .
some time you have to step up the torch tip size for a little bigger areas because if the area does not get hot enough then when you flash cool it the area is going to be big enough to shrink the metal to get rid of the oil caning .