gas threaded or pipe threadings normally get a greyish colored thread
sealer applied to them.  or you can use yellow teflon tape rated for
gas.  DO NOT apply anything to a flare fitting.  it interferes with the
proper sealing of the flare.  also the code inspector will not approve
the white tefon tape on a gas fitting.  (missed one and the inspector
caught it).  did a new gas heater installation in the house last year
and did it exactly by code on my first one(minus that one fitting).
jimt
On Saturday, October 19, 2002, at 09:04 PM, Bill Davidson wrote:

> I've got my new propane tank bolted to the under side...
> And I have cut and bent and flared tubing ends...
> ready to connect the tubing and tighten the flare nuts...
>
> but a question...
>
> I noticed that when I took the flare nuts apart there was a dark
> colored
> greasy like substance on the threads... and maybe on the flared ends
> of the
> tubing... Originally I though that might be old propane decomposed into
> sludge... but now I'm wondering if the previous installer put a dab of
> axel
> grease on the flares.... perhaps it assures a better seal???
> Anybody know what that black stuff is on the flare ends?
>
> thanks,
>
> Bill Davidson
>