Typically, 3 to 5 wraps of Teflon tape should be used when sealing pipe fittings.
Not necessary, but recommended along with pipe thread compound.
No, teflon tape (and pipe dope, for that matter) should never be used on flare fittings. They are designed to seal without tape or dope, and may actually leak if tape or dope is used.
Pipe dope better solution than tape.
yes
Many fittings, except unions, require the use of teflon tape.
No, using Teflon tape with oxygen fittings is not recommended as there is a risk of combustion due to the oxygen-rich environment. It's better to use specially designed oxygen-compatible fittings to ensure safety.
Yes, but only if it is necessary.
You do not need tape on any flared fitting, brake or regular. The brake line and the fittings are different size and thread type than regular copper line and fittings. You can't mix them.
Yes. Teflon is a compound of carbon and fluorine.
Blue Teflon tape is thicker and denser than white Teflon tape, making it more suitable for sealing larger pipe fittings. White Teflon tape is thinner and better for smaller fittings. For plumbing applications, blue Teflon tape is generally preferred due to its higher density and better sealing capabilities.
Taape or joint compound on the threads the same as any other pipe fitting, but not on the threads where the two halves connect.