(page 6-06) Gimme some skin....                

Vertical stab skeleton is complete, and the skin has been drilled and dimpled. The dimple die worked like a charm. Isham's tool kit even included the small diameter die needed to dimple the nut plates (not done yet). I had assumed I'd have to take the normal die to the bench grinder in order to do this procedure.

I did learn that the #40 holes should be dimpled before the #8 (larger) holes.  I started doing it the other way round and quickly saw that dimpling small after large distorted the large hole.  I recovered by re-dimpling the large holes.  Looks OK.  Dimpling all the nut plates required a lot of muscle on the squeezer.  I wish pneumatic squeezers weren't so expensive.

(page 6-05) Taking a break.......                             

...Then some actual progress.  The Spousal Unit forced me, kicking and screaming, to spend a week in the Keys, which severely cut into my progress on the -12   Actually, the kicking and screaming happened when she made me return to the frozen North (Carolina).

I did, however, get to visit the southern-most EAA chapter in the US, chapter 1241 in Marathon, Florida, which is about half way between Key Largo and Key West.  Amazingly, they average about 200 people at each meeting, putting to shame the chapters I've been affiliated with.

For the first time, I used Isham's pneumatic rivet puller, which came with the Isham's RV-12 tool kit. This tool worked better than I could have hoped for. I riveted the spar caps to the rear vertical stab spar, which involved a few squeezed rivets and probably 100 pulled rivets. Piece if cake. About half the rivets required the use of the little wedges, which were made early on, for riveting in tight spaces. They worked as advertised.

I finally came to the realization that deburring all the edges and holes will consume a substantial amount of time.  As previously mentioned, there are approximately 12,500 rivets, but each rivet goes through at least two holes, sometimes three.  That's a lot of holes.

After reading way too many builder blogs, I finally settled on a procedure for preping the aluminum for priming:  For every surface which gets riveted to a mating surface, I'm scuffing with red ScotchBrite, wiping down with acetone, then spraying with rattle can self-etching primer.  I think this is sufficient.

Finally, a part has emerged which, with a bit of imagination, looks like an airplane part: the vertical stab skeleton.  The skin may get attached tomorrow.

Pulled 8, Squeezed 8....                                                                      

Primed the horizontal stab rear spar and the spar caps which get riveted to it.  As an experiment, I tried the PreKote on the spar itself, scuffing with red Scotch Brite as I washed on the PreKote.  Rinsed with tap water, repeated, then did a final rinse with distilled water.

 For the spar caps, I simply washed with mild soap (again scuffing with Scotch Brite), rinsed and dried. No PreKote. According to people who should know, this should be sufficient.

After drying, I primed all parts with the self-etching primer. As the pics show, squeezing the flush rivets scraped off a fair amount of primer. The pulled rivets weren't a problem since the rivet tool doesn't touch the aluminum. I'll spray primer on the whole aft side of the spar before painting since this surface will be visible on the completed airplane.

Also, the female threaded part of the nutplates doen't seem to line up exactly with the holes in the spar web and spar cap.  If this is a problem when I install the bearings, I'll open up the holes a bit with a Dremel.  Shouldn't be an issue.
                             

(page 6-04) Gettin' a little behind....                   
..in the project.  I had planned to be much farther along at this point.  Not sure what the problem is.  In order to finish in two years (my goal), I need to put in about an hour and fifteen minutes per day, assuming 900 hours to complete the project (the high end of Van's estimate).          

At the outset of the project, I wondered why I needed an air drill. Seemed like a good battery-operated drill would be just as good. Turns out the air drill is much faster and makes a better hole, and, being a lot smaller, will get into tighter spaces. With this number of holes, it'll make a big difference. I bought Isham's tool package, which is specific to the RV-12. It was a bit cheaper than Avery's, but so far, I'm happy with it. Haven't tried the pneumatic-hydraulic rivet puller yet. Soon.

(page 6-03) Drill, Baby, drill.........                                      

Sarah Palin would be proud.  The buildup of the vertical stab appears to be mostly match drilling holes, clecoing and deburring.  The riveting will be fun by comparison.

I've spent an absurd amount of time researching, thinking about, even dreaming about the priming issue.  I ordered a gallon of PreKote, a product used to prepare aluminum for priming.  Seems like the US Air Force thinks this stuff is good, so I'll try it.  I've decided that there's probably little difference in the self-etching primer available in rattle cans.

First mistake...figured I'd get it out of the way.

One of the rudder hinge bearings was binding slightly in the bracket I fabricated yesterday, owing, I suppose, to a speck of paint in the machined recess into which the bearing race fits.  I saw this on another build blog I'm following, as well.  So....I now know how to drill out solid rivets.  I was a bit unhappy with both brackets because of a larger-than-I'd-like gap at the top.  I believe this results from squeezing the bottom-most three rivets first, so I'll squeeze the ones closest to the bearing first this go round.

(page 6-02) Rudder hinge: an actual part....               

I'm still a bit unsure about the issue of priming. Opinions seem to vary from "prime everything in sight" to "prime only the mating surfaces that aren't Alclad... and maybe not that." I suppose it boils down to whether or not I want to build an "archival" airplane guaranteed to last 60 years. Everything considered, that probably doesn't make sense.

I'm using Rustoleum self-etching primer in a rattle can.  It seems to scrape off too easily with a fingernail, probably owing to my improper preperation of the aluminum.  Cessna and Piper seem to use minimal (if any) priming on the interior surfaces, and the tail cones I've looked in seem pristine, even on 50-year-old airplanes.

I'm way behind schedule on building. The semester is essentially over, with only the grading of final exams left. The Spousal Unit (my beautiful, understanding and supportive wife, Karen) is heading up to the frozen north to visit family for a few days. I have assured her that upon her return there will be a completed part in the garage which anyone would recognize as an airplane part. She allowed as to how she'd be much rather see progress made on the deck rail. We'll see.