The Stovebolt Site Forums The Shop Area Engine Shop Gas line connections

When you make a non flared connections, such as threaded. Is there anything I should use on the threads to aid in sealing? I’m putting a glass bowl filter in front of the carb.

Thx Don

Don, I've never used anything and had no problem. Others may have?

I will say I've had some problems from previous owners ruining the connection due to tightening the living daylights out of them.

Permatex #2 is what I use.

Or there is a blue pipe sealer goop intended for gasoline, not the white stuff.

Neolube 100 is what we used at the power plant on pipe threads.
It would not set up and the threads would come back apart good also.
https://www.newmantools.com/chemicals/neolube100.htm

On engine gaskets, we used Permatex ultra blue.
https://www.permatex.com/products/g...sor-safe-blue-rtv-silicone-gasket-maker/

Don

Nothing is needed. You can more harm than good using something that isn’t fuel resistant.

You can also do harm over tightening if it doesn't seal dry, then the gas resistant sealers come in handy.

Permatex #2 is gasoline resistant, and everyone should have it on hand for gaskets already, also good on pipe threads. https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/

And this is the other I was thinking of, Leak-Tite Blue http://www.laco.com/pipe-thread-sealants/leak-tite-blue/

This I've heard is good but haven't tried myself, RectorSeal No. 5 http://www.rectorseal.com/rectorseal-no-5/

Thanks for the advise guys. I think I will try using nothing first and then go with something gas proof if needed. Unfortunately I’m using a rebuilt carb and it may have had the connection over tightened. Which was the case before.

Going with a new tank and lines too.🤗

Thx Don

My favorite non-hardening sealer is Permatex Super 300. (Not 3-D) It was developed to seal aviation gasoline fittings, so it's definitely useful on pipe thread fittings for fuel pumps, gas tanks, etc. Flare fittings do not need any sort of sealer, as the threads of the nut don't do any sealing- - - -the angle of the tubing flare and the part of the fitting it meets seals the liquid.

Nothing at first worked fine until I went for a good spin. The threaded connection at the carb had a very slow drip and the flared connection I made was dripping. I used Teflon on the connection to allow me to get the nut tighter.

The connection at the carb was “loose” due to previous owners over tightening because the nipple bottomed out before the threads got tight. I used some thick high quality Teflon on that.

I looked at a lot of carb pictures on the net and almost all of them had signs of gas leaking in that location. Even the trailer queens.

Thx Don

By Teflon, I hope that you are referring to something other than tape. Teflon tape has a nasty habit of disintegrating in the presence of gas, and then gets inside of the carburetor into places where you cannot easily get to without removing casting plugs.
Carl

Don, are you talking about a compression fitting or a flare fitting?

I had to use Teflon tape on the pipe threads due to worn threads, just keep the tape back from the first three or so threads, if your using anything on flare or compression fittings that means the flare or compression fittings need to be re-made.

The Teflon is back far enough to keep from getting in the carb. The flare may not have been big enough. The nut isn’t the best quality and I don’t have a tubing wrench. So the Teflon did what it is supposed to do, allowed the nut to tighten properly. And when I need to remove it it will loosen without destroying it.

Had a nice trip across the river into town today. Hard to believe it could run any better. Now I need to find new gears for the rear end so I can keep up with the 50 mile an hour gang.

Don

Get a tubing wrench.

Ed

I looked at countless pictures of the exact method I used. Many use Teflon to get the nut tighter.

Don

Your wife is probably looking for a hint as to what to get you for Christmas. If I didn't have a set already, a set of flare nut wrenches would be good...

Thankfully my truck only requires 2 sizes.

Don