Garnet As A Sheetmetal Media

Anybody have any thoughts or experiences using 80 mesh garnet at low pressure to cleanup small sheetmetal patch panels. I have a couple donor fenders from my '68 and am planning to use them to make some patch panels for a set of fenders that need much less work than the originals.

Will garnet heatup and cause warping issues?

I can get any media for the job, just have about 50lbs of 80 mesh garnet in the shop?

Appreciate any thoughts.

Thanks