PTFE ?

[ghostlymoron]

I always use ptfe tape on threads to seal them. It's clean and convenient and cheap.
If you're replacing the skin fittings PTFE isn't suitable for bedding them on - use Sikaflex.

 

[vyv_cox]

I'm replacing my Seacocks etc later this year- why shouldn't I use Sikaflex to seal the threads, rather than PTFE tape?

John

I almost always use Sikaflex 291 as I usually have a tube on the go. I'm not sure where this myth about making things difficult to remove came from. It's just a polyurethane sealant, not particularly powerful or adhesive. In the past I have removed many different fittings for a variety of reasons, all bedded on Sikaflex.

 

[Mistroma]

I almost always use Sikaflex 291 as I usually have a tube on the go. I'm not sure where this myth about making things difficult to remove came from. It's just a polyurethane sealant, not particularly powerful or adhesive. In the past I have removed many different fittings for a variety of reasons, all bedded on Sikaflex.

Good to know. I'd seen Sikaflex 291 advertised as Polyurythane Adhesive Sealant and had also noticed that Jeanneau didn't use it valves, elbows etc. Jeanneau dealers couldn't tell me what Jeanneau used but I did note that it was a hard setting sealant. That's why I decided to go with Rocol Oilseal. It seemed to meet all my requirements and specifically mentioned easy dismantling (and also set very quickly).

I have plenty of Rocol Oilseal left so will use that up but will remember that you've clarified that 291 isn't an adhesive. I never remember what the various grades of Sikaflex are used for and always have to look it up on-line. However, I've started using a few Toolstation sealants, so noted your comments about their PU40 on another thread. Thanks again.

 

[sailinglegend420]

PTFE is designed for use on tapered threads - it may not seal on parallel threads.
On tapered pipe threads PTFE performs a lubricating function, which more easily allows the threads to be screwed together, to the point of deformation, which is what creates the seal.

 

[dje67]

PTFE is designed for use on tapered threads - it may not seal on parallel threads.
On tapered pipe threads PTFE performs a lubricating function, which more easily allows the threads to be screwed together, to the point of deformation, which is what creates the seal.

That was also my (fairly limited, it has to be said...!) understanding. For info, I posted my approach in this thread:-

http://www.ybw.com/forums/showthread.php?286447-SEACOCKS-what-sealant-to-use/page3

 

[GrahamM376]

I use Hawk White on gas and water pipe threads http://www.screwfix.com/p/fernox-hawk-white-jointing-compound-400g/69694