Fuel tank ribs sealed

The five ribs that make up the fuel tank are now installed and sealed for the left tank. Very messy, stinky work! By far, my least-favorite part of this build so far. And there’s still more to do on this tank. And I still have a whole other tank to build!

I’m glad I masked off the areas on the skin first, it made things look much cleaner once the tape was removed. I think all my fillet and fay seals look good, but it looks like a few rivets didn’t seat properly as I was rushing to shoot them in – I’ll have to drill those out and try again.

I used 80g of part A + 8g of part B fuel tank sealant, and that seemed to be enough to complete this part of the job. It was also as much sealant as I could apply within the 2 hour working window. Luckily you can safely plan to clean up excess oozing sealant after the 2 hours, it was still easy enough (though not easy) to remove with acetone and a rag.

The instructions say to install the fuel line fittings on rib 101 and 105 prior to installing the rib in the skin – I don’t agree with this, as it made it much more difficult to accomplish the fillet seal, especially on rib 101 with the fittings that are very close to the edge of the rib. I’ll change up the order a bit when I work on the right fuel tank. I did make sure to protect the fittings with tape so that they don’t get plugged up with sealant – I’ve read several accident reports involving loss of engine power due to fuel starvation, caused by blockage. Here’s one. And here’s another infamous one involving an RV-10. So I’m trying to be very careful.

Not too many in-process photos to share since my gloves had sealant all over, but here’s some decent before-and-after pics. In the interest of time, I just used my finger to shape the fillet seals this time – I’ve done that before with silicone caulk and it seems to work just fine.

I taped off the fittings so that they don’t get plugged up

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