Time: 4 Hours
I decided to start the interior 5 ribs if the left tank today. The process that I used was to butter up the flange of a rib and clecko it to the top of the skin in a few spots towards the leading edge. After I did that with all 5 ribs I then flipped the skin over and clecko’d the bottom skin to the rib.
Once I had all the cleckos in I grabbed my bucking bars and the rivet gun to set some rivets. I will tell you this is a messy job setting all these rivets in wet ProSeal with the bucking bar. Once I set all the rivets is mixed up a prefilled 6oz ProSeal tube to make the filets around all the ribs edges and cover the shop head of all the rivets. These prefilled tubes are very nice since you don’t have to measure, you just push the plunger in to introduce the black accelerator and then twist to mix everything up.
Getting to the leading edge rivets was a challenge by myself but I was able to do it with a little stretching. I was real happy with every rivet and they all set really nice. Using the gun to make the filets and cover the heads makes that process real easy. Don’t get me wrong it’s still a messy job but it’s easy! I’m glad that you don’t have to enter these ribs into a beauty contest cause I made a mess in there, but all you need to do seal them so they won’t leak.
Those last photos are after a lot of clean up as I had ProSeal all over the skin from the rivet gun and my hands. I will get the right tank done tomorrow and start the outboard/inboard ribs too. Another fun day in the Hangar, I’m keeping my fingers that I have no leaks!
Time: 5 Hours
I had a good breakfast with a couple of fellow builders and spent a few hours talking shop this morning. When I got home I decided to continue the momentum I had built up yesterday. I grabbed the other tank and setup all the supplies I would need for the task. With everything set I grabbed the ProSeal and made the measurements.
I did the same procedure as before, I buttered the flange of the stiffener and placed it over the rivets and set them with my back rivet set. I then loaded up a 2.5oz disposable Semco tube to hit all the shop heads of the rivets. Since I didn’t get photos of this the first time I decided to take a little time with these for some.
I left the tanks sit for a couple hours so that I could get some house cleaning done for the week. When I was done I came back out into the Hangar to finish off the tasks I wanted to get done this weekend, stiffeners, fuel caps & drains. I cleaned up the fuel cap flange, the fuel drain and the fuel vent clip that gets attached to the fuel cap flange.
The deluxe fuel cap flanges have various thicknesses due to the curve of the skin. So they have several different length rivets that are needed. I grabbed those and cleaned them with MEK and laid them out so I knew which was which.
With those all set I decided to start with the tank drains first. They are pretty straight forward to rivet. I buttered the flange and clecko’d them to the skin. I grabbed my pneumatic squeezer and started smashing away. With all the rivets set I cleaned up the mess I made and grabbed the Semco gun to hit the shop heads of the rivets. It’s important to leave the space between the rivet shop heads as this is the route that water in the fuel tank will flow to the drain, water is heavier that aviation fuel and therefore sinks to the bottom of the tanks. The drain allows a way for it to be drained off.
Next up was to get the fuel cap flanges done so I grabbed the back rivet set and steal plate. These went fairly well but I had two rivets that just didn’t sit flat so I drilled them out and redid them. That process is not fun under normal circumstances and add ProSeal in the mix and it adds a whole lot of extra fun! Once they were set I cleaned the mess up again and covered all the shop heads and made a nice filet around the inside flange.
All in all I think they turned out fine, there are a couple of rivets on the fuel flange that are set a little high but I can live with them and I think once the plane is painted you will never know. I will let these sit for a few days to let the ProSeal cure before I start on the ribs. What a great weekend in the Hangar! Looking forward to continuing the sealing and having this task behind me.
I stopped by a fellow builder, Glen Vokac’s, shop today to borrow his safety wire pliers and visit for a couple of hours. He is in the later stages of his -8 fuselage and it is really fun to see his progress. He gave me a quick lesson on the tool and grabbed some .041 safety wire and I safety wired the two parts.
On my way home I stopped by the local Ace Hardware and grabbed a few things, a shop apron, nitrile gloves and some invisible gloves cream. That cream adds a bit of protection from the MEK that usually eats through the nitrile gloves. When I got home the first order of business was to clean all the stiffeners and the tank skins with MEK. Once cleaned I used the stiffeners as guides for laying out some electrical tape around them to help reduce the mess and give me clean lines when I was done ProSealing.
Next was to take the rivets and place them in all the holes of the skin and tape them in place so they were secure. No I could lay the skin flat and the tails of the rivets were protruding up through the skin. Glen and I started out with 50g of the white and 5g of the black to start. The ProSeal is made up of two parts and you mix it at a 10:1 ratio. Not to hard with the digital scale. I just placed a paper plate on the scale and zeroed it out. Then I could just add the white as much as I wanted and then add the black so that I had a proper ratio. Once the two parts are thoroughly mixed you have a medium grey color paste and this stuff is STICKY. Everybody says it gets everywhere and they are spot on! Once mixed I just used a popsicle stick and buttered the flange of the stiffener. Then I placed the stiffener over the row of rivet tails and used the back rivet setup in my rivet gun.
I didn’t take to many photos since I didn’t want to get any ProSeal on my iPhone. When I was done riveting I mixed up around 160g of ProSeal and loaded it into my disposable Semco cartridge and into the pneumatic gun. This setup let me apply a perfect bead along the perimeter of the stiffeners and allowed me to use a popsicle stick to smooth it out. Then I used the same tool to place a dollop of ProSeal on every rivet shop head. Wow I love that tool! It made this process very easy. I will be using it a lot with these tanks!
When all was done I removed the electrical tape to reveal nice clean edges. Out came the MEK to clean up all the extra ProSeal I had everywhere who’ve was pretty easy. I then removed the back rivet tape from the outside of the skin and cleaned any ProSeal that oozed from the rivets onto the skin. Next was cleaning all the tools which wasn’t to bad. You definitely use a bunch of gloves and towels in this process! All in all I was pretty happy with the process and just as excited to start this phase of the wings as I was with my very first rivet, this is a BIG step in building this airplane. Now that I have had the initial experience, thanks to Glen, I feel much more confident going forward. Glen gave his approval on each step and that means a lot to me since he is an OshKosh Lindy award winner with his first RV-8! Here is how they turned out.
Time: 2 Hours
I was able to get a couple of hours in the Hangar today to work on the anti-hangup guides. These guides keep the end of the flop tubes from getting caught between the 2nd inboard rib and the rear tank skin stiffener. It’s a little easier to understand in these photos. The first photo shows how the flop tube could get caught.
So I think I’m about ready to start sealing the tanks. I had one other task that I wanted to get done and that was to torque and safety wire the flop tube to the 90° elbow that will connect to the fuel lines to the engine. I needed a crowfoot open end wrench to attach to my torque wrench. So I headed to Sears since most of my tools are Craftsman and I have had good luck with the quality. When I got back I placed the elbow in my vise between two pieces of wood to protect it. With the proper torque setting and attached the flop tube.
I have been reading up on this task and have seen many comments on how to add a factor to the torque for the added length of the crowfoot. I was talking to one of our aircraft mechanics at our home base in Omaha and he have me a tip. He said place the crowfoot at 90° angle to the torque wrench and you don’t have to add and factor, just use the setting required for the type of fitting you are working with. Unfortunately I forgot to buy my safety wire pliers this last week, but I’m going to take my parts down to my friends house and he will let me use his. The safety wire will secure the flop tube to the elbow and not let it come unscrewed. That will get done tomorrow and then it’s time to ProSeal!