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In the past i have been told to use hemp and graphite on a pvc male thread into a female brass thread, ive found that ptfe tape almost always leaks, also a brass male thread in a female pvc thread normaly expands and cracks along the seam, what do u do?o
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i have never used hemp on pvc fitting male or female
always used ptfe tape up untill 1-2yr ago when quality dropped away - i use silicone tape now and it is good for gas as well as heating/steam applications
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dont use so much hemp on the fitting and it will be ok and use plenty of graphite for good lube...too much hemp will swell too much causing the plastic fitting to crack as you have seen...i used to worry about this as well but you actually only need a small amount of hemp to create a water tight fitting...just look at the tollerance between male and female fittings they are quite snug fitting so actualy only a small amount of hemp will do...generaly with brass fittings we tend to drown the thread in hemp...all so correctly "tease" the hemp so it is not clumpy or string like on aplication and you should be right....I donot and never will trust ptfe tape...all so you could use a brand of "gass goo" that is ok to use with potable water systems.