Tested the Fuel Tanks

Tested the tanks using the test kit from Van’s. Attached a balloon to the fuel strainer to regulate the pressure and as a visual indicator that the tank was pressurized. Used a spray bottle with soapy water to spray down the tank to find any leaks. No leaks found!

I attached the tanks to the wings but had to remove them because the tank skin overlapped the outboard leading edge skin by a few thousandths. I used a file to adjust the edge of the skin. I final-attached the tanks to the wings with AN3 bolts, torqued them to spec and marked them with torque seal. I got about half way through putting all the screws in. I’ll have to finish those up next week when I get back from Florida.

I’m definitely in the home stretch with the wings. Looking forward to getting everything buttoned up next weekend.

355bfa

Today’s Time (hours):	3.0
Wing Time (hours):	242.0
Total Time (hours):	394.0

Completed assembling left tank

Same drill as the right tank yesterday…

Both tanks are now fully assembled. I’ll give them a few days and then pressure test them to find and seal any leaks. Then I can attach them to the wings and move on to the bottom wing skins and aileron actuation.

Today’s Time (hours):	3.0
Wing Time (hours):	229.0
Total Time (hours):	381.0

Finished assembling right tank.

Added a bead of tank sealant for the baffle. Clecoed the baffle in place. Riveted the baffle to the ribs and then riveted the z-brackets in place. Then riveted the baffle to the skin.

Installed the fuel drain, the fuel sender, AN fittings, and the fuel cap.

Machine countersunk the holes in the tank attach bracket for #8 screws.

The right tank is now complete and once the sealant has cured, I can pressure test it. Hoping to get the left tank to the same state tomorrow.

Today’s Time (hours):	3.0
Wing Time (hours):	226.0
Total Time (hours):	378.0

Added nutplates

Short build session tonight… Got all the nutplates riveted on to the inboard edge of the tank skins.

The sealant is curing up nicely.

I also temporarily installed the fuel senders in order to tweak the float rods to ensure the proper clearances. I’l permanently install them with sealant after I’ve riveted the baffles in place.

Today’s Time (hours):	1.0
Wing Time (hours):	223.0
Total Time (hours):	375.0

Recommenced fuel tank assembly

Jared came by again today to help out. Thanks, man. You’re the best!

We got the fuel drains, fuel filer and stiffeners re-installed.

Installed the ribs in the right tank.

Made up installed the vent line for the right tank. Added installed the right tank attach bracket and aft inboard rib and filleted everything with sealer. Both tanks are now ready to be closed out with the rear baffle.

I cannot over state what a sticky, smelly, messy process this is. My shop looks like a sealant bomb went off. Every tool I own has some sealant on it now.

Today’s Time (hours):	10.0
Wing Time (hours):	222.0
Total Time (hours):	374.0

Cleaned up all the partially cured sealant

Started the day with a nice flight down to Aircraft Spruce at FFC with Jared to pick up some PolyGone. Great excuse to go flying!

PolyGone polysulfide stripper is the shizzle! This stuff really removes fuel tank sealant as advertised. I had a real mess on my hands and this stuff saved the day.

I slathered the PolyGone onto the partially cured sealant and let it sit for 30 minutes or so then used a plastic bondo scraper and rags to remove it. It took about four hours (not counting wait time) to get all the sealant off of the skins and all the stiffeners and other parts. It was tedious and messy but it worked and I got it done. Went through a lot of gloves and rags.

Back to fuel tank assembly tomorrow. I am so ready to be done with the fuel tanks.

Today’s Time (hours):	4.0
Wing Time (hours):	212.0
Total Time (hours):	364.0

Fuel Tanks: the struggle is real.

Fuel tanks are absolutely kicking my ass. I got back from Toronto last night and checked to see if the sealant had cured. The stuff I had applied Monday had hardened up nicely. The first batch from from Sunday was still gooey. Not cool. They came from the same can. So I must have made a mistake in mixing that batch.

I talked to Jared and Van’s. Consensus was that it may cure eventually but Van’s recommended that I re-seal these parts with properly mixed sealant. Unfortunately this meant removing 22 stiffeners, 2 fuel fillers, and 2 fuel drains. I had to drill out a couple hundred rivets and was left with a sticky mess. Thankfully the sealant on all of the ribs we had just riveted into the left skin was fine.

When the sealant is first applied, it wipes off easily with some lacquer thinner. Once it has started to cure, not so much. I’m headed to Aircraft Spruce tomorrow to pick up some PolyGone. It is specifically designed to remove polysulfide fuel tank sealant.

It was essential to my sanity that I make at least some modicum of forward progress today. So I bent up the rods for the fuel sender floats per the plans. Since the ribs were installed in the left tank, I was even able to fine tune the left sender to the proper clearances.

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Today’s Time (hours):	3.0
Wing Time (hours):	208.0
Total Time (hours):	360.0

Continued building left tank

Sealed and riveted the J channel stiffener to the tank skin.

Installed the tank attach bracket assembly and added a fillet of sealant to the seam with the forward rib. I used an inspection mirror to ensure I got good coverage.

Made up the fuel vent line and installed into the tank.

Sealed and riveted the aft inboard tank rib in place. I installed the bulkhead fitting for the vent line and connected the vent line to it.

I didn’t have enough sealant left to fillet the aft rib. So I’ll do that in the next session.

Today’s Time (hours):	3.0
Wing Time (hours):	205.0
Total Time (hours):	357.0

Made great progress on tanks

Jared cam over and helped with tanks today. I’m very grateful to have a friend that has done this before and is so generous with his time. I would never have made as much progress on my own. Learned a ton today.

Everything we did today involved fuel tank sealant. We used FlameMaster Chem Seal that I bought from Van’s. This stuff was invented by satan to torture builders. It smells like ass. It is incredibly sticky and gets on everything. Every part, every tool, every cleco, your hands, you arms, the work bench, the floor, EVERYTHING! I went through an entire box of nitrile gloves today. It is a two-part concoction that you mix ten to one by weight.

We sealed and riveted the flanges to the rear inboard ribs. Then we riveted the drain flange to the skins (after undimpling the holes that I accidentally dimpled in the skins). We riveted the fuel filler flanges to the skins. We riveted the stiffeners to the skins. We set up the left skin in the cradles, applied the sealant to the skins and then riveted the ribs in place.

Today’s Time (hours):	9.0
Wing Time (hours):	202.0
Total Time (hours):	354.0

Final drilled and dimpled tank skins

Final drilled and deburred all the #19 holes. Dimpled the #19 holes with the squeezer. Dimpled the #40 holes with a combination of squeezer, DRDT-2, and close quarters dimple dies.