Mike,
Just MHO, but the video guy's 4 different tests showed no real difference in the adhesion on the Kirker's primer. It seems scuffing may not really be necessary.
I do think it may be fine to use a
gently applied wire wheel to do the "scuff" work, if you have concerns about getting the best adhesion.
The "gentle" part may be the most important factor though from both a safety aspect and not doing any damage to your pieces.
As with any scuffing action, don't forget the follow on cleanup to remove any loose particles before applying your primer.
Dan
