Cleaning and priming of horizontal stabiliser parts completed!

Next step in empennage preparation was prepping the metal for priming, and then priming.

I am electing to follow the recommendation from the factory to prime only mating surfaces. This is much easier than having to deal with fully spraying all the parts, which is a much more involved process I don't feel is entirely warranted for 6061-T6 aluminum, which is already quite corrosion resistant. Priming mating surfaces is also what Zenith aircraft recommends, on the same aluminum alloy, for corrosion protection, as can be seen in this EAA video.

My approach:
  • I am using Stewart System's EkoPrime primer product, instead of the Cortec VCI-373. This is mostly because I can't quite figure out how to source the Cortec in any convenient manner. The Stewart Systems products seem to have a good reputation, and are easily sourced via Aircraft Spruce.
  • I am using a coloured product, in my case the Zinc Chromate Green. Many builders use the white version that turns clear after application. Because this is used *inside* the airframe, esthetics don't matter so much. I'd rather know where the primer was applied, and know it for a long time, so that any future inspection will be able to identify the primer and where it was applied. And I just think that green looks cool :)
  • I am following the Stewart Systems instructions:
    • Scuff up the surface with Scotch Brite
    • Clean with a tack cloth.
    • Dump tacky gloves, get new clean ones, and ...
    • Clean with isopropanol.
    • Apply primer with foam brushes.

Here is the "gear" needed:

And here is the final result:

Only slight issue is that in the end, there is some primer that ends up visible on the outside of the airframe ... the rear main spar of the horizontal stabiliser for instance, has hinges for the elevator, so this faces "outwards".

The primer can be removed with a number of solvents, as per Stewart Systems instructions, so I'll consider cleaning things up that way and let you know how I make out!