Section: 18
Hours: 8

I started out today by riveting in the j-channel. It's a little tricky buttering it with ProSeal and inserting it into the tank without making a big mess because it has to be slid in from the end of the tank. I enlisted Deb to help me and together we were able to maneuver the stiffener into the tank with minimum mess.

j-channel after riveting and touching up the shop heads with a dab of ProSeal.

Today I practiced cutting and flaring aluminum tubing before fabricating the gas tank vent line. I had ordered a pipe cutter and flaring tool late last year and they arrived last week just in time for today's project.

All the DIY articles I've read say you need to practice with the flaring tool. They were right- it is tricky learning how far to insert the tubing and when to stop twisting in. I went through 7 tries before I felt like I was getting the hang of it.

Here's the flare I put on the vent tube.

The vent tube runs the length of the tank and ends 1/4" from the outboard rib just past the gas cap flange. I hand bent the soft aluminum tubing to go through the lug on the gas cap flange. The manual shows the vent making a straight run through the lug, but I bent it to place the end a little closer to the highest point in the tank (unless the RV is in inverted flight...).

After installing the vent line, I riveted in the attach bracket and the upper portion of the end rib.

The AD4 rivets that go through the attach bracket and the flanges of the upper and lower end rib pieces ended up being the hardest task today. I couldn't reach the rivets with the squeezer so I had to use the bucking bar and rivet gun. To make it even more fun, I had to use the bent stick on the rivet gun because the rivets are close to the rib. Also, there were minimal clearances on the shop side in the corners and around where the #6 rivet that plugs up the registration hole sits. To get the corner rivets I used my thin tungsten bucking bar. I boosted up the air pressure to slightly over 60 psi to set these rivets. Did I mention that in addition to all the above challenges there was gobs of ProSeal oozing out of every crevice and gumming up the works.

Here's the end rib and attach bracket after setting the rivets and adding a generous 3/8" fillet.

Several builder's have reported getting leaks from the corners underneath the attach bracket. Before inserting the attach bracket I dabbed some extra ProSeal in the corners where the bracket meets the tank skin. After riveting in the attach bracket, I reached under the bracket and dabbed some more ProSeal into the corners for good measure. Here I'm checking the result using my inspection mirror.

All the ribs and stiffeners are now in riveted in.

I put a protective layer of cardboard on my work table to catch the drips of ProSeal. The other work bench has the scale, acetone, mixing supplies and construction manual.