Elevator Ready for Primer

Not much to show for a couple of hours of work tonight.  I think I've built and disassembled this elevator at least a half dozen times.  Just as soon as I think I've caught everything they neglected to mention in the plans and take everything apart for the "final time," I find one more hole that needs to be addressed or something.  This section of the build gets nodding smiles when it's talked about on the forums, so at least I'm in good company.

The bottom skin/spar has the option of using either pop rivets or solid rivets.  After a lot of reading and research, I've landed solidly in the pop rivet camp.  Sure, I prefer the look of solid rivets, but since only people laying on their backs looking up at the elevator will see these rivets, I just don't care enough to put the effort in for solid rivets.  There is literally no way to buck these using normal tools because the spar flange is open on the forward facing side (so you can't reach in the trailing edge side to hold a bucking bar).  People who do decide on solid rivets usually end up fashioning a 4 foot long bucking bar that they try to slide between the leading edge and spar.  No thanks.  Sounds like a nightmare.  I'll trade some pop rivets to save what I'm guessing is a couple of hours of riveting and cussing.  I'm very unlikely to care what rivets are in the tail when I'm done and flying.  So anyway, I bit the bullet and drilled the larger holes into the spar for the pop rivets (1/8 vs 3/32), so there's no turning back now.

After taking everything apart for what I desperately hope is the last time, I finished deburring everything that I hadn't done already.

The last thing I needed to do tonight was dimple the holes for the spar.  Given that these are right at where the skin is rolled, it's not exactly easy to handle it all using the c-frame dimpler.  I started on the bottom, knowing full well that I'd probably discover a technique issue that I'd rather learn about before moving to the top skin.  Sure enough, I had a little trouble initially.  There's a hesitation to open the skin up far enough to really flatten out the area for the dimple die, and that cost me a few "smilies" in the line of spar holes.  It's hard to see in the picture, but where I marked is where I wasn't super happy with how the dimple die contacted the skin.  The dimple is good, but the die dug into the skin a little bit because the rolled edge wasn't pulled down and away enough.  Not a big deal, and truly probably not even noticeable, especially once paint goes on.  You can see in this picture the 1/8" holes for the blind rivets vs the 3/32" holes in the rest of the skin.

I (hopefully) learned my lessons on the bottom skin and moved on to the top side.  My biggest lesson was that I could really flatten the skin out an awful lot without causing any damage.  For this side I put a lot more effort into holding it down with the palm of my hand while I also held the dimple die in place with that hand.  It's a little awkward, but doable.  I only had a few very small uneven hits with the dies on the top surface, so am pleased with how it came out.  The top skin gets riveted onto the spar first while there is still open access, so it uses all solid rivets, hence the 3/32" holes on top for the spar.

Aside from needing to dimple a couple of holes in the tips of one of the ribs that I didn't get to tonight, I'm ready to prime.  I didn't do those holes because they are in an extremely tight location, so I need to switch gears and either use the pop rivet dimpler or the hammer/dimple approach like we did on one of the earlier ribs from the vertical stabilizer.  The weather is now solidly Seattle fall weather, so I'm going to have to figure out priming in colder/humid weather.  It's unlikely I'll be able to spray outside, so I'll have to sort something out for doing it indoors.  That's a huge reason why I purchased the EkoPrime product - much less toxic since it's waterborne and doesn't use the nasty carcinogenic stuff.  Spraying it inside will be much less of a concern if I need to do that over the winter.

Of course, tomorrow I have to make a trip to the aviation aisle of Home Depot.  I need to pick up a piece of aluminum angle to use when riveting trailing edges. In order to make a straight trailing edge using the wedge that goes between the skins, you need to fix the wedge to the skins using either tape or proseal (I'm using the heavy duty 3M double sided tape they recommend) and fasten it to a straight piece of angle for a few days while the stuff cures.  Then you can rivet with less concern of it warping.  Van's says to shoot for less than 1/10" of wave, since more than that can cause differences in handling.  

Once again, the order Van's has you do things in for the elevator is just strange.  They have you prime everything and rivet most of it together before starting on the trailing edges, meaning that you have to match drill, dimple, countersink, etc in the skin which has already been primed.  So I'll probably have to touch up some scuffed up parts before riveting the trailing edge.  I know it's nothing to worry about, considering a completely unprimed plane would still likely outlast my lifetime.  Given that this plane will likely live in the Pacific Northwest for a while though, and to top it off may not have a hangar since those are insanely rare and expensive around here, I am just trying to give it the best shot of staying in good shape for as long as possible.

I have a few days off from work, so hopefully I can hammer out the right elevator, finish the trailing edge of the rudder, and get the left elevator started by the end of the weekend.  If all goes well, I should be starting the wings sometime in the next month.