Re: thread sealant question
Teflon tape can be used but you have to be careful. If it's all that's at hand, use it but don't wrap the first two threads, thus trapping the tape within the threads.
Any Teflon paste would work, Permatex is just a common brand found at most auto parts stores.
Loctite thread sealer works but can be tough to remove, especially with aluminum threads.
There is a thread sealer/thread lock compound used in the HVAC trade which is basically a cross between blue thread lock and Teflon paste. But as with blue loctite, it's not really recommended for use with alcohol products.
Years ago when I was dealing with pumping methanol racing fuel, we used this stuff to seal the threads on the fuel pump piping threads:
http://www.jmesales.com/item/103266/Gasoila-2-Oz-Tube-Soft-Set-Thread-Sealant-W-Teflon.aspx
Keep in mind that the alcohol content in gasoline will have only a minor effect on these sealers, Loctite 242 would loose say 5% of it's strength when used with ethanol, but that test is only at 100 hours. There's a huge difference in sealing E-10 or E-15 vs. pure alcohol, ethanol, or methanol fuel.
I use Permatex thread sealer, or which ever brand I happen to find first, I've never had a problem. Keep in mind that in most cases we're sealing soft aluminum threads to a harder brass or steel nipple, which if tightened properly would most likely seal with no sealer. The purpose of Teflon Paste is to lube the threads and to seal any imperfections just in case there may be any. I would also think that Teflon paste would have some benefit when dissimilar metals are used since it does help prevent corrosion too.
