Screwfix compression fittings

[Dave Plowman (News)]

Crikey - as well it should be at the price.

[Andy Hall]

instructions in invisible ink.

We had a boy at school who tried to make this claim regarding his French homework (that he hadn't done). He was given the cane for that.

[Andy Hall]

I've used this one for coarse thread applications such as radiator tails into radiators and fittings into HW cylinders. It does do what it says on the tube which is to be suitable for this purpose. In context, it's not that expensive (£15 for 50ml bottle) because only a tiny amount is needed. For lubrication of threads on compression fittings (which shouldn't be needed if decent ones are used), there are cheap generic PTFE sealers from plumbers merchants, but these are not much cop for coarse thread sealing.

[Dave Plowman (News)]

I had a really awkward to get at copper to threaded plastic connection to make (toilet cistern) which refused to be leak free. But the Fernox worked a treat on that so impressed me no end. Not easy to do as I'm sure you'd agree. ;-)

[Andy Hall]

The trick with those is to leave the securing nut that holds the valve to the cistern loose and to screw on the tap connector first. Then do up the securing nut.

[Ed Sirett]

The fittings are to BS 864. Are you saying that the fittings are claiming to be to BS 864 but in reality are out of spec?

[Dave Plowman (News)]

I tried about every combination. Including of course a new washer on the tap connector.

[Dave Baker]

With respect no it doesn't really. A liquid or a gel like silicone will squeeze out of every part of a compression joint where's there's metal to metal contact and only remain in the imperfections you actually want to fill however small those are. PTFE squishes about a bit but it still remains in strings and will preclude the metal to metal contact you want to achieve in the parts of the joint where there aren't any imperfections. It's fine (well see below) for its purpose which is primarily to seal coarse threads but it's not at all the right stuff for compression joints.

As it happens I dislike the stuff in general because it doesn't always seem to do a very good job of sealing threads either. I've tried it in small applications of just a couple of turns, redoing the joint with lots more turns and I've still got a couple of immersion tank fittings that just won't seal properly. I think the ideal stuff is a semi-hard setting glop that you can slap on as thickly as you like and leave to go off before turning the water back on. I'm sure one of the 'boss white' type compounds or gas fitting seal compounds is a much better bet than PTFE. When they replaced my gas meter some years back the bloke slapped on about half a pound of some brown coloured glop on each joint which squeezed out everywhere and dried to the consistency of very hard plastic. You can just mark it with a fingernail but that's about all. If every part of a joint is filled with something that's completely impervious to the fluid in question then frankly I don't see how it can leak. Compared to that PTFE is a fairly hit or miss approach.

[The Medway Handyman]

What a good idea - ta!

[Andy Hall]

Invoice for consultancy services in the post :-)

[no$spam!delete&abuse%dave]

In message , Grunff writes

does that apply equally to natural gas compression fittings?

[Andrew Gabriel]

Yes.

[no$spam!delete&abuse%dave]

In message , Andrew Gabriel writes

Thanks.

[no$spam!delete&abuse%dave]

In message , Doctor Drivel writes

just found an old tin of Hawk White - has that been superceded for (gas) threads by these newer materials?

[Doctor Drivel]

"dave @ stejonda" wrote in message news: [e-mail]...

Yep. Read the specs first. Some ate not WRAS approved (for potable water) but fine for gas and others.

[Doctor Drivel]

Just look at the quality of them.

[Doctor Drivel]

[Doctor Drivel]

..and it still leaked..........of course...

[Doctor Drivel]

Loctite 575 and Fermox do this.

I am no fan of PTFE tape while superior sealants are around that require no tape at all.

[Andrew Gabriel]

They are very specific about not using a saw to cut the pipe. There's even a pictogram in case you can't read.