I started out today putting all my efforts into finishing up the bottom of the left wing.

When I installed the winglets onto the wings I had 2 functional wing dollies, but since I have no room inside my shop they’ve had to live outside in the weather.  The one wing dolly I’m using here, although weathered and unsightly, is still operational. The other one (much older of the two) is rotting out in spots… in short, with only one wing dolly I have to get the left wing finished to get to working on the right wing.

I first spent over half an hour doing a final sanding on the micro finish of the outboard bottom wing, bottom inside winglet and bottom winglet intersection fairing. I had a number of major divots from air bubbles in the micro, as well a myriad of smaller yet distinct depressions and holes as well, which I remedied with a quick round of micro & West 410 mix applied to these offending aberrations.

I then got to work on the left wing aileron pocket’s bottom lip, sanding it for about 45 minutes to widen the gap between it and the front lower edge of the aileron (which is the embedded aileron weight rod).  I was able to sand the aileron pocket edge away to give me a hair over a 0.1″ gap, with the minimum per plans being 0.08″.  Obviously, I want to have a little extra to allow for paint.

I had other tasks on my list that I had planned to work on, but it looked for a few hours that a thunderstorm might be passing through, so I continued to focus on the wing.

Sins of the past….

My next task on the bottom of the left wing (once again moved outside in front of the shop) was to A) do a final sand on the previously boat-paint-primed bottom surface, and B) remove as much of the boat paint primer as possible since I’m now going to shoot the paint vs roll it on.  I will note that this primer is as hard as nails and takes a good bit to get it removed.

Moreover, as I was working near the inboard edge, I found a linear bump that after further investigation was clearly a delam.  My guess is that when glassing in the extended lip to attach the oil cooler I must have set a heat lamp too close and caused this delam… but I’m not 100% sure.

After doing a bit more aggressive sanding to get down to glass, I used both a large washer (quarter tapping) and pushing with my fingers to find the area of the delam, which it certainly was.  You can see the ridge marked above and with the ruler “riding high” in the pic below.

With it being a longer narrow delam, I drilled 4 holes down the center, and a couple more holes with one on each side of the perimeter. I then mixed up some MGS 335 with fast hardener and injected the epoxy into the holes.  I had both a taped up long narrow block and my clamp ready to go, which I employed immediately following the epoxy injections.

Another shot of the inboard bottom wing delam repair: clamp securing taped block in place.

After dealing with the delam, by this point my added micro to outboard bottom wing micro’d areas was cured.  I spent another 30 minutes sanding all that down so that this area is all ready for epoxy wipes.  But as it was past 8 pm, I punted on the epoxy wipes until tomorrow.

I then spent another good hour sanding the boat paint primer down on the bottom of the wing.  Here’s a shot of where that took place outside the shop.  I’ll note that I tried using both my air file and electric orbital sander but found that what worked best by far in this task was my new jitterbug pneumatic pad sander.

Here’s a better shot of the primed and now sanded left wing bottom surface inside the shop, under the lights. I will probably do another good round of sanding towards the middle outboard area of the wing, since there’s still a few shiny spots that can be seen under lights.

And yes, I will incur a slight weight penalty by not removing all the primer completely, but I’ll note first that it is serving as a filler in leveling out the high and low spots on the bottom surface of the wing, which under the lights and to the touch is very uniform and smooth.

Secondly, I am pushing hard to get this bird done, thus time is of the essence.  Sanding down this primer takes a fair bit of time, and more importantly I don’t want to do any damage to the finish of the wing or have to start over in the finishing process due to excessive removal of the primer.  I’ll take the slight weight hit and press forward.