I'm not sure, but being a gas line it had better be right, correct, and code.

Creative Homeowner - Dream ~ Design ~ Create.

This website for homeowners and flared fittings makes no mention of any tape or dope.

Thanks brickeyee. The tape was applied to the threads of the flared end, the end that the threaded collar fits over.

Will this make it likely to leak?

Thanks

Applying the tape to only the threads of a non-tapered fitting will not cause a leak. It is the inside bell of the tube and the outside angled portion of the fitting, where the bell of the tube makes contact, that you need to keep clear of tape or other debris.

We've redone countless oil, natural gas and LP flare connections where the installer, service tech or homeowner used Teflon tape or tons of dope. While most of these connections aren't leaking, we pull them apart to make sure nothing is on the metal to metal flare connection and to make sure the surfaces of the flared connections are in good shape. Some people use tape because they don't know any better, and some use it because they had a leak, so either way it raises a red flag.

I have found numerous leaks in flare and compression joints with tape applied by the original installer. Removing all traces of the tape and tightening the fitting properly almost always solves the problem.

Metal to metal connections come in a wide variety of styles. a flared fitting is just one. All M to M connections will benifit from lubrication both on the threads and on seal surfaces. They all will tend to leak if chunks of teflon or other solid stuff gets on the seal surface. Most pipe dope contains shreded or powdered teflon or other fillers. don't get them near the metal to metal seal surfaces. dope or tape just on the threads is ok and may help the seal, but it's safer just to not use them at all.
grease may be used and will help the metal seat and seal better. Grease on the threads helps to get more force to the seal area. Just make sure it has no solids mixed in. Rub a little between your finger and thumb and if it feels or looks the least bit gritty, don't use it.

Brass and copper are relatively soft and have pretty good lubricity even without any grease. They will normaly make up and seal pretty reliably even without grease. Steel flare fitting definitely will benifit from being greased. Stainless steel flare fittings almost require a grease with good anti-galling properties to function.

I'd be curious to know if the selling outlet knows that their delivery guy is telling people how to make connections and is actually making connections. I bet their insurance company would go nuts.

I wonder if that delivery guy wouldn't have to have a plumber's license and/or a gas ticket to legally make that gas connection?

Puting tape on flare joints is like putting tape on joints that have a rubber sealin it .The tape takes to much space on the thread,therefore you dont need any.

I'm an engineer, but before I finished engineering school, I became a certified HVAC tech to work to pay for college. So I have both technical training for flare fittings AND I have engineering knowledge of the same.

There are always special case emergency-only exceptions to this, but if you have a special case you are probably doing something wrong or are using the wrong parts. Flare fittings are designed to be installed dry, and without sealing tape. Teflon tape will lubricate the fitting to make it easier to tighten, but it also lubricates the threads to make it easy to loosen. THAT is a bad thing, the natural friction of the threads is factored into the design. A flare is a compression fitting, and that compression is provided by the design and grip of the threads, and redesigning that by making changes such as adding teflon tape means you are no longer using the equipment as designed. Unless YOU are also an engineer, with the proper liability insurance, you are not qualified to redesign the connection. Worse, things like homeowners insurance is looking for an error to blame a loss on that is not covered by the policy. Doing your own electrical or plumbing work means you may be voiding your insurance policy if you do *anything* wrong. Insurance does not cover fire loss caused by improper installation or repair.

Tapered fittings use pipe dope or teflon tape. ALL compression fittings, including flare and gasketed fittings, are designed for clean dry threads, NO tape.

The one and only one thing you can do to add a sealant to a flare fitting is to add a flare seal. A flare seal is a plastic washer in the shape of the flare bell. These should only be used in solid fittings, where a copper flare is not present, such as a John Guest to flare adapter (for water lines). A flare seal is used to repair a leaky fitting, but usually means there is something wrong with the connection that should really be fixed properly. You should not need flare seals for new installations. A leak is usually caused after a connection is opened up, and there is some damage or corrosion of the seal surface. A leak on a new connection means you did something wrong.

After fourteen years I fail to see any added value .