Use of Teflon Tape on fuel fittings

[pjfsail]

When installing national pipe thread fittings on a diesel fuel system is it a good idea to use Teflon Tape?

[Silmaril]

Don''t do it!!! I just installed (then re-installed) a complete new fuel system on my 37'' sloop. Everything new, from the deck filler, right through to the lift pump on the 3GM30F, and new return lines as well.

I used teflon tape the first time through, I have some 1 1/2" npt bronze fittings going from the tank through a bulkhead to the fuel hose. Each one leaked just a drop when the system was filled for the first time.

I then had to drain the tank and take everything out, clean it, and re-assemble it all over again. This time I was using Teflon PIPE DOPE/JOINT COMPOUND, and my biggest stilson wrench to ensure that everything would be tight and leak free.

On pipes under 1 1/2", just coat the male threads and sock them down good and tight. On 1 1/2" and up, coat both male and female and tighten well. Be careful to not go overboard using too much pipe dope, as excess will clog up your first filter.

Good luck.

[pjfsail]

Silmaril, thanks so much for the warning. I use Teflon tape in my job, Landscape Maintenance. When I began replacing my fuel system I automatically reached for the Teflon tape. I stopped and asked the question and am sure glad I did. Thanks again. I''ll go get some Teflon pipe dope/compound before going any further. Regards, Peter

[RichH]

Better to use teflon tape than teflon pipe dope.

Less chance of the ''carrier'' in PTFE pipe dope from dissolving leaving the PTFE particles free to migrate down the piping stream. PTFE dope is notorius as a ''particle generator, PTFE tape wont ''particulate''.

[pjfsail]

RichH, thanks so much for your input, but now I''m no better off than when I first asked the question. I have two opposing views on the subject from folks who have totally different experiences using Teflon Tape and Teflon Compound. What is a guy to do?? I would encourage both of you to respond and others too on their experience using Teflon Tape and Teflon Compound on fuel fittings. I do appreciate your response. Thanks, Peter

[JoseASantin]

Teflon in a fuel system is a bad idea all together. It would be safer to use some of the gasket compounds(silicones) that are sold in auto parts stores, make sure they are formulated to be used with oil and fuel applications.

[Silmaril]

OK, so I have done some more research on the subject. The Product I used, Retorseal T plus 2 is not a good way to go. <sigh>

The diesel rated product for long term exposure is Rectorseal No. 5. Same process for application, it is pressure rated to 350 psi of diesel with no leakdown after 720 hours.

As mentioned by others, the manufacturer sayes the Teflon products will have their carrier desolve over time, and then eventually leak. Not to mention all the teflon particals that will clog your filters.

I will be taking the system apart over the winter and clean and replace all the fitting''s coatings with their diesel rated product.

[pjfsail]

Silmaril, thanks for your input. Can you tell me and the forum what research you have done and where you got the information? I would like to find out what you found. Where does one get the product Rectorseal No. 5? What is Rectorseal No. 5 and what makes it so good? Thanks again for your input. Peter

[Silmaril]

I went to some plumber friends first. They recommended the Rectorseal product as being very good. Being plumbers, they were the ones to say "Go with the teflon" go figure, hey they''re plumbers...

After reading the post regarding the teflon compound breaking down, I called the manufacturer. Getting in touch with their technical support group was easy, describing the conditions, ie: bronze threads, diesel, etc. they recommended their "No. 5" product, citing it''s excellent proberties with bronze threads and diesel.

http://www.rectorseal.com/slnts.htm

[pjfsail]

Silmaril, I truly appreciate your response and the research you have done. In looking for additional information I went to a local marine dealer/service department in our community and asked him what he recommened. The manager told me to use Locktite Blue. He regularily uses Locktite Blue on ALL fuel fittings he works on. He comments he has NEVER had a fuel fitting leak and that they are relatively easy to take apart as opposed to the RED Locktite which requires about 550 degrees to remove. I bought some Locktite Blue at our local hardware store and used it to put my fittings together. In doing so, I had to reposition two fittings and found they came apart with some effort but they did come apart. At this juncture I have not experienced any leakage. Many thanks again for your input. Regards, Peter