Tank progress

The Proseal becomes easier to work with after a little practice.  I finished the stiffeners on the right side tank after the left side was completed, and riveted the VA-112 drain flange in place.  These rivets can all be reached with a hand squeezer.  I placed a layer of Proseal on the drain flange surface that attaches to the outside of the tank skin, then covered the rivet heads on the inside of the tank with a good sized dab of Proseal.  I countersunk the holes in the fuel cap flange, and fabricated the fuel tank vent clips for both tanks.  The fuel cap flanges are now ready to be riveted and Prosealed. 

Right side stiffeners riveted and Prosealed

VA-112 drain flange attached

Fuel cap flange countersunk to accept dimples in tank skin

Fuel vent clip fabricated and clecoed in place

Begin fuel tank assembly

With the fuel tank stiffeners cut, deburred and dimpled and the skin prepped, it was time to begin Prosealing the left fuel tank.  I reviewed the several methods people use to accomplish this task, and reached out to a few of my builder friends.  I decided to use the following procedure to Proseal the stiffeners to the tank skin:

• Thoroughly scuff stiffener and skin attach area with maroon Scotchbrite pad
• Clean stiffener and skin with acetone
• Place a small dab of Proseal in dimples from the outside of the tank skin
• Insert rivets and tape in place with rivet tape
• Apply a thin layer of Proseal directly to stiffener and place stiffener over rivets
• Back rivet stiffeners to tank skin
• Use syringe to run a bead of Proseal around perimeter of stiffener.  Smooth with popsicle stick to form nice filet
• Place dab of Proseal on each shop head, completely covering shop head and dimple
• Check for gaps in Proseal coverage, and fill accordingly

After using this procedure for several stiffeners, I decided to try applying the Proseal directly to the skin rather than to the stiffener.  Using a hobby paintbrush with the bristles cut down, it was easy to apply the Proseal to the skin and obtain a nice uniform layer.  This method worked better for me.

Workbench covered with plastic sheet to keep everything clean

All materials laid out for convenient access

Thin layer of Proseal applied to stiffener

Alternate method - apply Proseal to skin with syringe and spread with brush

Back riveting stiffeners

Left side tank stiffeners completed