It’s been quite chilly the last couple of days, so no major composite work in the shop, although I did get some smaller tasks done utilizing heat lamps.  It’s forecasted to be warmer for a couple days coming up, which is when I plan on epoxy wiping the left wing and winglet.

Since it’s cooler in the shop —and given that I want to embed some threaded inserts into the top of the left wing as hard points, pre-epoxy wipes, for mounting a video camera— today (and last night) entailed a lot of lathe work.

Since I’m out of any stock of “baggage pod” threaded inserts from the Cozy Girrrls, I decided to make some myself.  That being said, I should have paid more attention to their dimensions since a while back I ordered some 1/2″ aluminum 7075 and 2024 rods thinking off the cuff that that’s the natural diameter they’d be… uh, a quick check on the Cozy Girrrls’ site and I realized they use 3/8″ diameter stock, vs 1/2″.  And why waste metal and add any weight if not required.  Thus, I punted and did the first batch with some 3/8″ diameter 6061 aluminum I had on hand.

After some knurling, I started by drilling the center hole out (pic 1) to tap the 10-32 threads (pic 2).

Unlike the Cozy Girrrls I added some flox grooves on the side to give the inserts a bit more of hold inside the drilled hole (pic 1).  I then parted off the threaded insert and started the process all over again (pic 2).

Here we have a 3/8″ diameter 6061 aluminum threaded insert, replete with flox grooves in the side.  It’s a little hard to tell, but another improvement I made was that the end that goes into the hole is enclosed, so no more having to tape up that end before installing it.

Another couple shots of the threaded inserts I’m making.  Again, at this point specifically for securing some camera mounts to the outboard wing tops, and also on the top of the left winglet.

First two threaded inserts, hot off the lathe!

I placed an order for some more 3/8″ diameter 7075 and 2024 rods, among a bunch of other bits and pieces, that will come in Monday.  I didn’t want to wait to make some threaded inserts a little more robust than 6061, which is fine (probably for all the inserts in reality) but I wanted one in each pair to be higher strength 7075 or 2024.  I decided on the 7075, which I turned down from 1/2″ diameter to 3/8″… enough for 2 more threaded inserts (pic 1).  I then knurled the surface to provide a textured surface for the flox and micro to grip (pic 2).

And here is the sum total of last night’s and today’s efforts: 5 threaded inserts (3x 6061 and 2x 7075). [Unfortunately the lathe was giving me some grief that I had to contend with, so it took a few hours longer than I had planned… sigh].

After drilling 3/16″ holes on each end, I pulled the cured left wing video camera mounting base off the wing surface.  I prepped a 7075 threaded insert, applied grease to the screw threads, added some clear packing tape to ensure a good release, and drilled the forward hole out to 3/8″.

I added flox towards the top side of the threaded insert, with some flox also into a widened spot right under the wing skin (think washer, or donut) to lock in the insert.  On the bottom half of the hole, since it’s all wing foam in there, I simply used micro to set the threaded insert.  I then inserted an AN3 sized screw into the aft hole to ensure it was aligned correctly (pic 1). I then weighed the forward hole down to ensure the threaded insert was set in place and cured nicely (pic 2).

I’ll note that due to the curvature of the wing, and thus video camera mounting base, I’m installing one threaded insert at a time.

I then determined the position of the right wing video camera mount, which is a little more than an inch further outboard than the left side.  Since the right wing is already epoxy wiped, I put down a piece of yellow adhesive to ensure no errant epoxy gets on the wing.  I then marked the position of the video camera mount and added clear plastic tape over top of the mark.

I then wet out a piece of peel ply first, then 5 plies of glass (BID-UNI-BID-UNI-BID) just as I did on the left side (pic 1) and finalized the layup with peel ply on top (pic 2).

With all my composite work out of the way, I finally got around to the initial sanding of the epoxy wiped strakes to knock down the slathered on epoxy.  As I did on the right wing, I used my orbital sander with 80 grit to carefully knock down the epoxy wiped surface.  I did have a couple break throughs on the left strake, as well as nicking the left wing’s leading edge, so I will be doing some re-filling and re-sanding on those spots.

I plan on wet sanding the strakes with 150 grit tomorrow, as well as continuing to prep the left wing and winglet for epoxy wipes.