As I am really avoiding having to start cleaning edges on the ribs, I decided to make the stiffeners for the left fuel tank.

Vans delivers some long pieces of stock angle to be used to create the various length stiffeners.
Both tanks will carry about 160 liters of fuel, 80 kg in each tank so a little extra support for the skin is no luxury.

Fortunatly, Vans has already made some notches on the stock angles that show you where to cut and round corners. This makes this task really a no brainer. Trust the notches and snip away, no need for extra measuring.
They even have foreseen the shortening of the inboard stiffener for allowing water to drain down to the lowest point in the tank near the inboard rib.

First step, just cut the long bars in parts using the aviation snips. Then use the band saw to remove roughly the corners. Last, our dear friend scotchbrite will grind away the last part and polish the corners.

A word of caution: don't prime any of the inside of the tank ! The primer may react on the fuel and start peeling of or contaminate the fuel.

A piece before and after.

Then isntalled the stiffeners on the skin, clecoed and matchdrilled them. Mark the position of the stiffeners on the flange with a sharpie pen.

Finally, deburred the holes of stiffeners and skin and dimpled the stiffeners for 3/32 rivets with the pneumatic squeezer.

As you can see, there are 4 lengths of stiffeners. The shorties and then 3 other lengths that are very close.

I assembled all my courage and started working on cleaning edges of the fuel tank ribs. All are done with vixen file and V-deburr tool. Next step is the scotchbrite in the die grinder. But that will be for next time.