I made the fuel and vent lines inside the cabin with 3/8” aluminum per the plans. I don’t find making the lines difficult, but it is definitely time-consuming as you try to bend and maintain proper alignment of the tubing. I normally cut the tubing about 2 or 3 inches longer than needed and form the section with extra tubing on both ends. This allows slight adjustments between the two ends before final cutting. Once satisfied with the piece, I cut and flare one side and temporarily install it in place before cutting and flaring the other end.
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