Do you put tape on gas lines or just pipe dope only

Pipe dope is the preffered method in the plumbing industry.

Hi Arthur

Although they do make a specific tape just for gas piping, I would recommend that you stick with the non-teflon based pipe dope like number 5 rectorseal for natural or propane gas piping... see image. Rectorseal is available at all home improvement stores.

Mark