what are reflection, refraction, and diffraction?
Best offer and good luck.The cost of repair is too much you would be lucky to et $100.00 for it
They both seal and make the joints easier to tighten. For gas piping there is a special yellow teflon tape that should be used although results are mixed among users. Pipe dope is usually not recommended for plastic. It's best to read the label of whatever product as some pipe dope varieties will work with natural gas but not recommended for LP.
