Builder Tip #79 from HomebuiltHELP 
What's the proper Torque for AN818 Flare Nuts?
How tight is tight to keep fuel and oil flared connections from leaking ?
If you routinely assemble flared tube fittings and have no problems with "leakers" then you can skip this tip. Many experienced mechanics have the feel for tightening these flare nuts properly and do not use a torque wrench.

Many builders of homebuilts do not have that experience and creating reliable, leak-free connections is not an intuitive procedure. Too loose and the connection will leak. Too tight and the connection can leak and even crack the aluminum fittings. These are critical connections for fuel, brake, and oil cooler lines that we cannot afford to have fail on our aircraft!

The type of aluminum tube or flex hose used in the flare connection will determine the torque required - they are not all the same! This video will show you where to find the source of torque values to use and the procedure to tighten the nut using a torque wrench.

 A routine but critical need to tighten the right amount to keep things from leaking
The material of the flared flange determines torque
Method of using a torque wrench to tighten

The Basics of Fuel Plumbing for Homebuilt Aircraft explained

Our  Fuel system Plumbing DVD  is the perfect way to get up to speed if you are involved with installing a fuel system in a homebuilt aircraft. Even if you are building a kit , the details for working with fuel components are not explained by the kit manufacturer. Because of engine options and customer's desire for improvements in materials (upgrading rubber to hard line tubing for example) much is left to the builder to use good judgement in selecting and implementing proper fuel plumbing parts.

Our DVD explains  the  tools and procedures  for plumbing an experimental aircraft fuel system utilizing:  rubber hose, metal tubing, and high-tech flexible hoses . Target audience includes those that have never worked with rigid fuel lines and their fittings before! At just $39, this is a great value - Order one today! Press button below for details about this DVD
Components for creating a flared connection
Every device needs a fitting to establish a connection
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