Van's Air Force
Western Canada Wing |
[Charlie is an RV-8 builder and regular contributor to the RV List. This article originally appeared as a post to the RV List—Webmaster.]
Yesterday I opened the package containing my fuel tank fittings. While inspecting the 90 degree bulkhead fitting, I noted that it had debris inside of it. In a past life as an aerospace machine assembler, I was taught to always carefully inspect all fittings and flares carefully before using them. Obviously, you don’t want to use anything which is scratched on the flare mating surface. When in doubt, throw it out!
All tubes and fittings should be flushed with solvent before installation to clear out debris and preservative coatings. Assembled lines and fittings should be flushed again before final assembly using solvent and air pressure. Cap one end of the line/fitting/assembly. Partially fill with solvent, cap the open end and tip, roll, shake, etc. Drain the solvent and blow out with air. Repeat as needed.
We used 111-triclorethalene (spelling?). It’s not the sort of thing that you find at the local Builder’s Square. There is one product which removes grease, oils, and grime, evaporates without leaving a residue & is readily available. Buy the aerosol cans of BRAKE CLEAN available at your local auto parts store. I have no brand preference. I do prefer the old clorinated rather than the new, safer, non-clorinated types. It works better. You take your choice. Using a proper painter’s mask and nitrile gloves (Harbor Frieght, MSC, McMaster-Carr, etc.) will protect your skin and lungs from the fumes.
Last year someone else on the list posted an excellent suggestion upon finishing the fuel system. Sorry I don’t remember who to attribute this to. Fill both fuel tanks with several gallons of fuel. Disconnect the fuel line from the carburetor/fuel distributer and attach a rubber fuel hose to the line. Place the other end in a suitable container. Operate the electric fuel pump till you’ve emptied both fuel tanks. This flushing operation should be repeated till all debris is removed from the fuel system. Don’t forget to check the gascolator after each run. As the recent thread regarding fires has made everyone aware; this is a critical system. Here, cleanliness and good workmanship are imperative.