I've installed the fuel tank fittings today. To seal the pipe threads I used Loctite 567. The RV guys seem to have good success with this stuff. Sonex generally recommends using teflon paste however that seems to be hard to find here in Aus for some reason. I made sure first the Loctite 567 would not attack the plastic si I used the bit of scrap plastic I cut off the filler neck to test this, I put some of the Loctite on there and left it overnight, no problems.
