Pipe tape/dope

Teflon tape, pipe dope, 'tpe' dope - any differences?

--->Paul

Difference that I've found is after years of being screwed together, pipe dope will come apart easier than tape and looks like the day you installed the joint. But I've had both hold for years without problems.

Since it's buried galvanzied pipe, I suggest you buy some roofing mastic, thin with gasoline and paint the pipe and joints. The pipe will last for ever that way.

T_Bone

I really like the part about the dope/tape helping get things apart 10 years from now - it was a bear trying to get one elbow loose down there in the bottom of a 3 foot hole with no room for leverage! :)

Thanks again all, & hope I didn't start a plastic air line feud again! We use a lot of black plastic for underground water runs, but not much of any plastic in the buildings. Can you glue up a plastic pipe in zero degree weather, that is a major thing stopping me from using it around the farm outdoors? Things always break for me under the worst conditions - funny how that is! Also does your type of plastic take freezing water in them? In another application the metal lines by the barn often freeze up, only have a valve that gives out every couple of years, the pipe itself seems to stand the constant freezing. I'm told it shouldn't, but for me it does...

--->Paul

I should have added that the easiest way to spread roof mastic is with a elbow length rubber glove, then toss the glove when done.

Another plus of metal pipe is when it does freeze a you can thaw out the pipe faster with more heat than PVC can take.

There again I'm a metal man and not a plastic lover.

T_Bone

The main reason I use thread compounds is not so much for preventing leakage, (comment about proper threads comes in here) but so I (or somebody else) can get it apart 10 years from now without excessive cussing !

Teflon tape is fine if your fingers are nimble, it's not cold and you're coordinated enough to do the wrap properly. Otherwise I use what's now sold as 'pipe dope'.

Both will work just fine if used properly.

Have you considered Schedule 40 plastic? I've ran plastic piping in my shop for air pressure, I have it regulated at 90 psi., an water is at 40 to 60 psi. It's cheap, and a heckuva lot easier to install. If you do have a split, it's very easy to cut out and repair.

This is actually some piping in a 7' deep pit for the water supply to the cattle here in Minnesota - replacing the leak-back valve & old pipe near it, 1 1/4" pipe & valve on a gravity feed system, so sealing isn't even that imortant with the low pressure.

Since this pipe supports the valve, my pressure on the handle turning off & on, and the vertical pipe to surface, I really prefer good old fashioned steel on it. :) Also if things freeze up or break, steel is easier for me to deal with on repairs in 20 below temps, or hot water/hot flame to thaw out.

Otherwise the plastic sounds good. I hear bad things about it for air tho.

--->Pauil

tape: neat, cost more, must be applied in proper direction, can cause problems with some close fitting valves if it enters flow stream.

dope: messy, cheap,

there is a proper number of turns to tighten for each size of pipe (not too tight, not too loose) i'd have to look it up though.