Sealing threaded couplings

[goodnoisefella]

Ooo, here we are again in the room of new paint....it's all a bit flakey in here, all the pics have gone away and the smileys are reluctant to show thier faces.
....lets hope this works, then.
I'm fitting my woodburner and the BSP to compression elbow coming off the boiler spigot refuses to point in the right direction and be tight at the same time....I've taken it to bits repeatedly and wound more (or less) PTFE to try and get it to be tight (and therefore, might not leak) but it always seems to turn another 7/8th of a turn before it locks up. Infuriating!
If I only had to back it off a 1/4 turn, I reckon it would be fine, but 7/8 of a turn makes it feel really loose, it's never going to be watertight.

Plumbing gods out there, what's the technique?

I thank you kindly.

Tim

[northern installer]

Tim,boss white and hemp will enable you to adjust the angle a little without leakage,just a b :ogger when you want to dismantle it a year later!

[northern installer]

while on the subject,make sure you properly identify between taper threads(self sealing) and parallel threads,which need to pull up between flanges with a washer between;And be careful with ptfe on taper threads,too much umptee on the stillsons trying to line it up can result in a burst socket,and much swearing!! 

[goodnoisefella]

Cheers NI,
Yes, I'm a great beliver in boss white...but with hemp,eh? Right!

...it does seem to spin right in, up to the shoulder on the elbow....I was considering fibre washes in there to pack it out a bit, so I got the right angle when tight.......
D'ya reckon ordinary red fibre washers will be man enough...it's right next to the fire

Thanks

Tim

BTW fellas, the site is beginning to sort itself out (I can imagine frantic keyboard thumping at Navitron towers, right now)

.............Anyone remember 'The Numbskulls' in the Beano?.....that's what I imagine, behind the scenes at Navitron......er, no offence, of course, chaps

...Oooo, and a spellchecker tool now, too!  spanky!.....Better put 'Navitron' in it's dictionary, though.

Tim

[northern installer]

fibre washers will be fine if trapped between two flat and true machined surfaces,any amount of taper or similar will just result in them splitting out of the joint.Fibre washers are designed to be used on joints like an immersion heater boss in your cylinder,you will see a true and flat flange face on the boss and on the heater,and the threads are parallel,the seal being provided by the fibre washer (on no account use boss white here,its unnecessary,and will result in disaster when you need to replace the immersion htr. )

[guydewdney]

from plumb centre - jet blue. Useable on hydraulic, steam, water , potable water, air lines. brilliant stuff, im a convert. 10 quid a tub

[goodnoisefella]

I don't think I've got anything unusual here, N.I.....It's just a hunter stove with a boiler....If I had the space behind, I'd use a straight connector, crank it up nice and tight, then an elbow....but as it's all a bit tight at the back there, I'm trying to do it with a 28 comp/ female elbow. There is a nice machined flange at the base of the thread on the elbow that would take a washer well.

Cheers guydewdney,
That sounds good, Is it a silicone goo, like LSX?

/TP

[djh]

Ooo, here we are again in the room of new paint....it's all a bit flakey in here, all the pics have gone away and the smileys are reluctant to show thier faces.

Actually, it's rather nice that the pics have gone away! Or at least, when I'm at work, I'd prefer to be able to have them not appear!

Congrats on the move
Dave

[guydewdney]

GNF - no - its more of a thin paste - like hummous! toothpaste? Red hylomar? wipe it on, (then off your fingers) and do it up.

My airline needs spark plug tightness now - wereas before it needed head bolt tightness. smells a bit.

[goodnoisefella]

Thanks gents, we have it cracked!

Got a pack of fibre washers that were too big, cut them down to size.....used toenail clippers...perfect radius! Haha

gave a good slather of jet blue round the threads and washers, and with careful choice of washers, it nipped up tight to the perfect angle.

..just about a dozen more joints and I can get some water in the blasted thing.

Grateful for the tips,

Cheers

TP