The Long EZ Build: Fuel vent lines and screens

Before moving forward with the top strake skins, I had some fuel tank prep work to do!

Step 4 of Chapter 21 has us install vent lines and a "finger-strainer" to protect the fuel system from large size contamination.

I started out by drilling a hole on the forward top section of B23 to fit the 1/4" aluminum vent line...

Test fitting the diameter... perfect!

CP#27 under 'Builder hints' warns us that the main vent line might leak a bit if you are parked nose down - a temperature rise will cause the air/fuel in the tanks to expand and push fuel up through the vent line. To help prevent this, the CP suggests a secondary vent line located at the far aft top inboard of the tank.

So I drilled a hole through the aft portion of B23 for my 2nd vent line...

I then drilled two holes through the fuselage to route the vent lines through the fuselage walls and up into the turtle deck...

I made sure the holes were located just below where the top strake skin will be installed later on...

Notice the two holes through the fuselage wall just below the top longeron...

I then fed the aft vent line through first...

1/4" aluminum tube bends pretty easily without any special tools.. I just left them extra long to be trimmed later...

I then routed the forward vent line... along my aft BAB bulkhead and through B23...

Looking good!

These will be trimmed at a later time when I decided how I want to expel them through the turtle deck or make a "vent line canister" - which serves like a plenum to route all vent lines into. I'll create another post for that when the time comes.

And then repeated for the other side...

Before floxing the vent lines in permanently, I focused on the screens so that I could flox everything up in one shot.

The plans say to use an "aluminum screen standard from a hardware store". Problem is, these days, most hardware stores only carry plastic or nylon screens. So I went to Target and purchased two stainless steel strainers.

I used a dremel to remove the dome mesh...

I then sanded/prepped all surfaces that were going to mate with flox... including the area around the fuel drain...

Before I could install the mesh dome, I had to figure out a way to hold it in place while it cured. So I Macgyvered a simple solution - I took a spray can cap...

And drilled two small holes through the top...

I then shaped a wire into a "U"... passed it through two holes of the mesh.. and up through the cap..

Putting a small bit of tension on the line, it held the screen mesh in a perfect tent...

The plan is to apply a bead of flox around the perimeter of the mesh.. and let it sit there until it cures...

Ok, with everything prepped, it was time to mix up some flox! I started out by painting plain epoxy on all surfaces that will see flox... including the surfaces of the vent lines...

I then applied flox with the lines already in place...

And then applied 1-ply BID over the flox...

Notice the tape protecting the tube from any epoxy/flox from getting inside...

The screen mesh perfectly positioned..

The next day when everything had cured, I clipped the wire holding the cap off.. the result was a perfect screen over the fuel drain...

I then focused my attention to seal up the space between the floor layups under the openings... I still had bare foam here. This is because I did the tank's floor layups AFTER I installed the ribs and bulkheads. No big deal... I started by sanding all surfaces...