How much PTFE?

[AndersonC]

Quick question to help me here:

When people say "put some PTFE tape on" - how much is some?

How many layers of PTFE tape do people wrap round a thread to seal it?

Or does it not matter?

Thanks

 

[Expertboy]

What are you sealing?

 

[AndersonC]

All kinda stuff, flexible tap connections, a slight weep on a 15mm copper compression joint, a 2" nut on an old bath waste pipe connection etc. Will be connecting radiators up soon as well.

From the question I assume that the amount depends on what you are doing?

 

[nstreet]

I normally use about 3-4 turns on a 15mm fitting. The larger the fitting and coarser the thread the more turns you will need.

 

[ChrisR]

flexible tap connections,

None at all. A washer goes under the tap end

a slight weep on a 15mm copper compression joint,

Could try 3 turns round the olive. Don't ever put it on the threads of a compression joint.

a 2" nut on an old bath waste pipe connection etc.

None at all. A washer goes under the waste end. And its probably "1 1/2" "

Will be connecting radiators up soon as well.

They often need quite a lot on the part which goes into the rad. Roughen the thread a bit, wind tight, in the direction which would go tighter if a nut gripped the thread as you screwed it on. May need as much as 20 turns. Press the tape into the thread afterwards, best to run your thumbnail round. What you're trying to avoid is the tape being pushed off when you screw up the bits.

You always have to use your head - think where the water is supposed to be stopped from getting out past the joint. Amateurs often put tape all over the place where it's doing no good at all.

 

[Agile]

Another point that amateurs sometimes dont know is that you only tighten a PTFEed joint in one direction.

If you decide to unscrew it then that will spoil the sealing. Its usually PRVs where people go wrong because most types only tighten 3.5 turns to line up the outlet.

Tony

PS What keyboard keys can I use to get a proper small "1/2" ? Isn't it already embedded in the standard keyboard character set?

 

[doitall]

Programs, System tools, Charactor map, ½"

 

[ChrisR]

a proper small "1/2"

Alt + 0189 on the keypad
½
Accessories>System Tools>Character Map , select a char and the codes come up. Or copy and paste.

 

[AndersonC]

Thanks for the advice chaps.

 

[Agile]

Yes thanks for all the ½½ ½ ¼ ¼ ¼ ¾¾ ¾ ¿ ¿ ¿

 

[lorraine]

another tip worth mentioing is where you have a male/female thread such as when you change a washer on a stop cock, make sure you wrap the ptfe on clockwise. Otherwise as you tighten it will come off.

Lorraine

edit: fixed my slipup!

 

[doitall]

ptfe should always go clockwise when viewed from the end of the thread.

 

[Nige F]

unless the stopcock is BS666 which has a left hand thread

 

[doitall]

unless the stopcock is BS666 which has a left hand thread

Never seen one of them Nige F, are the made for Hartlepoole only

 

[BertieGas]

You ned to find out "where the joint is made", and put the ptfe there. Most people slap it all over to no avail. British Gas technical bullitin used to specify ELEVEN turns of PTFE on a threaded joint. They used to employ people to work out a spec for everything.