Prepping Second Side Skin
Over the weekend I started preparing the port-side outer fuselage skin for installation. There are a few steps to do before installing it:
- Lightly abrade the skin near rivet locations (for better paint adhesion under the countersunk rivet head)
- Dimple the forward rivet locations
- Attach NACA duct
- Roll edges where they overlap other skins (bottom, aft)
- Attach insulation
- Mask and prime overlap areas
I also had a small wiring task to complete. I never finished routing the power and data line for the canopy lighting. I finished routing it out to the outer skin, where it then travels up through the aft-most longerons to meet up with the canopy.
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5302.jpg?resize=678%2C509&ssl=1)
For dimpling, I’m using a few tools that I bought from Aircraft Tool Supply during their Oshkosh week specials:
Since I don’t have a lot of holes to dimple, I didn’t want to invest in a Deep-Reach Dimple Tool (DRDT2), so instead I used an air hammer along with the die block set to create the dimples. The air hammer is a cheapie $10 variant from Harbor Freight, but I can’t argue with the results — the dimples are nice and crisp. I laid out the skin on a large work surface, and had the die block on a shorter bench just below the skin to ensure the dimple die halves would meet up normal to the surface of the skin.
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5301.jpg?resize=678%2C509&ssl=1)
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5292.jpg?resize=678%2C509&ssl=1)
As before, I used Dow 732 RTV sealant between the NACA duct and the skin. I also again used backing strips made of 0.020″ aluminum to support the rivets, since countersinking the thin edge of the duct removes too much material for countersunk rivets to work.
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5294.jpg?resize=678%2C509&ssl=1)
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5304.jpg?resize=678%2C509&ssl=1)
Before I went much further with the skin install, I wanted to make sure the 10mm x 170mm landing gear bolts would be able to easily slide into the holes on the uprights. There are other holes for large bolts where I had to use a reamer to open up the holes a bit. Luckily, no problems with the fit, as shown in the next photo.
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5297.jpg?resize=678%2C509&ssl=1)
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5298.jpg?resize=678%2C509&ssl=1)
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5295.jpg?resize=678%2C509&ssl=1)
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5299.jpg?resize=678%2C509&ssl=1)
![](https://i0.wp.com/sling4.jetshine.net/wp-content/uploads/2020/08/img_5300.jpg?resize=678%2C509&ssl=1)