I decided to prep and prime the practice kit to smooth out the process before starting on the airplane. i don’t know if this is the final process, but it was I did for the practice kit.
First, I scrubbed all of the surfaces to be primed with a soapy red scotchbrite pad. Then clean with acetone and let dry, then prime with a medium gray self-etching primer. I’ll continue tomorrow.
One of the skins, primed and de-blued. Stiffeners, doublers, trailing edge wedge, spar, and ribs ready to rivet.
Stiffeners, doublers, trailing edge wedge, spar, and ribs ready to rivet.
Andrew's RV-7 Build Log 
What primer did you use? Where’d you get it at? $?
I am using NAPA 7220 Self-Etching Primer. I picked it up off the shelf of the local NAPA auto parts store (they also have an automotive paint supply store attached (it’s a distribution center, I think), but they should have it at any of the smaller stores.