Here's what the RV-12 manual has to say:
The traditional primer used on aircraft aluminum has been Zinc Chromate. With proper surface cleaning, this is still a good primer. However, there are many newer primers available which are superior. Most of these are two part, catalytic curing primers.
DUPONT VERI-PRIME #615 AND 616S
DITZLER DP-40/50 EPOXY
TEMPO brand chromate (spray can)
PRATT & LAMBERT Vinyl Zinc Chromate, EX-ER-7 and T-ER-4 Reducer
SHERWIN WILLIAMS WASH PRIMER #P60G2 and Catalyst Reducer #R7K44
MARHYDE self etching primer, available in a spray can as well as quarts
Primers like P60G2, Vari-Prime and others are relatiely inexpensive, light and easy to apply. ... They do need to be sprayed with a gun....
Some aerosol primers are useful for small parts when you don't want to set up to spray a whole batch....They are impractical for painting the whole airplane or large skins.
Generally (not everyone will agree) it is accepted that two part epoxy primers provide the best corrosion resistance. However, they are expensive, toxic, heavy and dry slowly all of which makes them problematic for the home builder. If you can tolerate those issues and want your RV to be in good shape when your grandchildren inherit it, they may be "best" for you.
Van's Aircraft does not have an "approved" primer. We use Sherwin Williams P60G2. This is used on the QBs and prototypes made here. ... We use this primer because it is inexpensive, dries fast, and is easy to apply. Sherwin Williams will tell you that the primer needs a top coat. True, for optimum corrosion resistance, but Vans feels that this is not necessary for the way in which most owners will maintain their RVs.
Last edited by lawspud : 05-17-2008 at 10:49 AM.