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Have a look at the image attached, got called to this leak inside the wall and its pretty obvious what went wrong. ???
I realise that there is no problem using PTFE assuming you know how. Overseas (USA or Europe) all they use is PTFE this is due to the fact that a tapered thread is used on both sides (including female fittings), is some cases all they use is a paste on its own and it will never leak. In NZ most threads are not tapered and hence if you don't know what your doing it will leak!
How do you train your guys? Do you trust them using PTFE instead of Hemp?
As far as I know there is nothing in the standards about where you can and cant use PTFE. I personally believe everything should be hemped (unless otherwise required by the manufacturer like on HWC to prevent electrolysis or on solar panels due to overheating) call me old fashioned but at least I can sleep at night knowing it will never leak. This by the way was done by a AU qualified plumber. gud onya mait.. :-X
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wHY DID THE PTFE TAPE wind off the thread Plumber?...was it because he didnt wind the tape on tightly when dressing the fitting or some other reason(i would love to know why? please?)...i only use hemp because it is bullet proof...but on the odd ocassion i use ptfe for example a female trap connector on to a basket waste/or a 8mm plastic water filter connection but have never been taught on the correct use of ptfe i just found myself that if you wind it/stretch it on tightly to the thread so it gets pulled into the fitting it will work but any movment could result in leakage...and behind the wall fittings where you have no means of testing you need to use a method (like hemp) where you know it will swell to ensure a watertight fitting.....I have got my boss into the habbit of putting our 80mm vanity nipples in with a brass cap on them before pre line inspection to ensure no leakage is happening...it also makes fit off a hell of a lot easier as vanitys can be a prick to work in esp wall mounted ones.
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hi guys, yes the classic case of not ruffing up the thread before applying the tape, i would use a hacksaw blade or similar to stop the tape from slipping backward, in any case i never use tape on a joint that is going to be a permanant fixture only use on temporary connections, if i have to use pvc valve sockets i put a small amount of hemp on the thread first then the tape also after ruffing the thread a little,cheers
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I agree with you thunderhead. I think every apprentice needs to know how to hemp properly before they touch PTFE or learn to use a screwdriver before they start using the cordless drill LOL. ;D
The problem with our NZ threads is that they are not tapered (unless your using galv) so the PTFE needs to be applied in a tapered form, start thin then thicken up as you work back (cone shape). On this specific job the plumber (well spotted Robbo!) simply didn't roughen up the thread, as he was winding in the thread the PTFE was winding out.
Some guys are aware of the fact that you need to buy brass fittings that are tapered (usually gas) but in most cases these fittings don't have the DR stamp on them (dezincification resistant) this simply means you cant bury them. so need to be careful.
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hi guys, quite often i buy fittings from Bunnings as they have a new store close to where i live. Don`t know where these fittings are from but are individually packed and have manufactured score marks on the thread saving one operation also they are cheaper than my prefered supplier(Micos)even with the G.s.t. included, dont know if many of forum members use Bunnings but although my prefered supplier is exellent and the staff great some prices when compared have been as much as 600% different,cheers
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cheers for the info guys...i wasnt sure if you had to roughen up the threads like hemp but know i know and work the ptfe tape into a cone shape when using cheers peoples for that info...but i am and will always be a lover of hemp lol
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A bit late, I just got your comment ".but i am and will always be a lover of hemp" :o
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hope your not like this with your coustomers plumber :P ;D :P
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lmao, me too!
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>> How much PTFE (thread tape) do I put on a thread?
Hi Guys, I thought I would update this thread because I have been asked this question last week. Any alternative answers are welcome.
I have been taught to apply the following formula [Diameter of thread x 2 / 10= total rounds (full 360 degrees)]
So if you have a 15mm thread its 15x2=30/10 = 3 times or if you have a 80mm pipe then its 80x10=160/10 = 16 times. Hope this helps.
By the way I always add just one more to the result :)