Prosealing the right fuel tank, left wing leading edge & lights
TLDR
- Prosealed the right fuel tank
- Test fitted leak testing kit but ran into problem
- Installed landing/taxi lights on left wing
- Clecoed left leading edge
Tank
The process took an entire weekend with help from my wife and my dad. I would say it is not possible to do it by myself. I really needed help from time to time.
Overall, I used 3 tubes of 3.5 oz proseal, plus 1 full pint. Pretty sure I went overboard with the proseal, but /shrug/ I really want to make sure the tank passes the leak test on the first go.
I have yet to conduct the test(more detail later). Hoping to do the test some time next week.
Day 1
The ribs
The first step I did was the ribs. Per the KAI, I smeared some proseal along the front plate channel and pulled the sealed rivets. Then I applied an additional layer of proseal on top.
Skin
I applied plenty of proseal on the skin where it attaches to the ribs.
Then sitting the skin and ribs on a table, I clecoed one side. For the other side, I moved the half clecoed skin into the tank jig to give it some clamping power. I clecod the other side of the tank skin.
During this process I was very aware of the time. I think I was at about 1 hour mark since I mixed the proseal at this point.
Fitting to wing
My wife and I lifted the clecoed tank (without back plate), and we matched the rivet holes with the wing and I put in some clecos to hold it it place.
Riveting skin
Then we started the rivet process. My wife planted the rivets on the top side when I pulled the rivets on the bottom side. When she was done with the top side I was about half way done on the bottom side. Then she helped to take the rivet stem off my hand as I pulled more rivets. The milwaukee rivet gun I use does not automatically dispence the rivet stem towards the back. I had to pull it out and manually throw it away. During the proseal process I really wished I didn’t have to manually throw away the stem because it was proseal everywhere. Everything was super sticky and very unpleasant.
Day 2
After the skin, I thought day 2 would be easy. I “just” need to install some small parts and the back plate. Boy that turned into a full day project.
Small parts
Prosealed and riveted the following stuff:
- Fuel cap,
- drain sump,
- fuel sender,
- overflow fitting,
- fuel inlet,
- fuel return fitting,
- Plugged a few manufacture holes
Fuel sender
Worth noting is the fuel sender. When I bent the steel arm the other day apparently the length and angle are just suggestions. What really matters is the the actual ohm reading when the fuel sender is actually installed.
So I had to do this experiment quickly before proseal sets.
I installed the sender to its final place, and moved the arm up and down to test the ohm reading. The reading was slightly off so I bent the arm a a little to make sure it can touch bottom and top of the tank skin. After that, the reading became within range. I am happy with the result, so I tightened the screws to specified torque value.
Back plate
While the black plate is clecoed on the tank, I first installed the doubler plates.
Then I took off the back plate, and applied tons of proseal, especially the corners, then riveted all except the 2 rows of rivets on the edge.
The edge rows required jus the regular rivets, not the sealed one. But there a 4 rivets on each side really hard to get to.. They need to pulled from the tank side (not the skin side), and I had to shorten 2 of them to make sure the rivet shop end does not touch the skin once pulled.
Problem with testing leak
Essentially I bought pressure gauge, end cap, air pump connector and a bunch of fittings. My plan is cap the fuel overflow, connect air pump to fuel inlet, and connect a pressure guage to fuel return fitting.
Everything worked except the fuel return fitting. The AN6 fitting does not thread well with connectors.
Normally I turn the AN6 connectors by hand at least 3-4 turns until the fittings stop moving, then tighten with wrench. But for this particular one the connector only turns smoothly for 1 turn or maybe less. This happens to both left and right fuel return fittings. Tried to force it a little and saw some thread shavings coming off, decided to stop forcing it any further.
Sling technical suggested to rethread or replace. Since it’s already on the tank, I super doubt I have enough space to rethread but really hoping that space is enough. The way I see it, I have 3 options
- Force it
- Rethread
- Replace
If force it works, then problem solved. However if it doesn’t work, I suspect it will cause damage to the fitting that rethread won’t work either. Then I will have to replace the fitting.
I think I will try to rethread first if the space allows. If space doesn’t allow, I will try force the fittings to meet. If neither works, replacement!
Left wing
While waiting for the proseal to cure, I started to work on some light projects on the left wing.
Trailing edge
With experience from right wing, I used hand squeezer to install AN470AD4-3 rivets on the left trailing edge.
Landing lights
This time I installed the lights to the rib before installing the rib to wing. This is so much easier to do. I had so much space to work with.
Then riveted the rib to the wing and connected to wires. Tested with a battery and no problem found. Lights are lighting and ribs are ribbing.
Clecoed leading edge
Started from the bottom, clecoed 4.0 holes first, then 3.2 holes on each rib.
Wrapped around to top side, clecode a few 3.2mm holes on the rib leading edge, but couldn’t align the holes towards the wing. So I used a racheting strap to hole the skin, then clecoed everything together.
