What makes flexi's fine done hand-tight/nipped up?

[WaterTight]

Is it just the fact they have a rubber washer or is also something to do with the design/thread?

If you put a rubber washer in a soldered standard tap connector (perfectly sized for sake of argument) would it then also only need hand tight plus a nip up?

Thanks

 

[sammathias]

Exactly the same as say a pushfit tap connecter...they have a rubber seal and wouldn't leak if only hand tight...if I ever had to use a flexi it would certainly be nipped up past hand tight tho.

 

[rpm]

If you compare rubber to let`s say a fibre washer then the rubber being softer makes a seal with less torque. Overtighten a rubber washer and it tends to disform or have I completely miss read the post.

 

[ShaunCorbs]

I nip half a turn past tight

 

[WaterTight]

So it's just the washer then. Cool. Shaun did you say you use hep conical washers on soldered tap cons because they are a great fit or did I imagine that in some fevered and strangely tedious dream?

 

[ShaunCorbs]

think that was town wt and i think it was

 

[Best]

It was probably me who mentioned the flat rubber Hep washers to use in copper tap fittings.
If the tap tail, or fill valve/ball valve tail is flat ended, then washer should be flat.
Conical washers would be better on the tapered tails designed for an olive. Although a compression nut and olive there would be best imo.

 

[Phil]

15MM HEP20 FLAT TAP CONNECTOR WASHERS-RUBBER PK OF 20 HX58/15 | eBay

Yes! these have changed my life since Best recommened them.

 

[Welder]

Rubber washers (just like O-rings) seal best when compressed between 10 & 20%. Past that and they begin to distort or even tear depending on their 'shore' rating (softness/hardness). They do not leak if done up this way.

HOWEVER. If the thing being connected is movable, this rarely gives enough tightness to accommodate the potential movement. You have to make a judgement cal in those circumstances and occasionally I have changed rubber to fibre so it can be done up tight.

 

[WaterTight]

Interesting.

Firstly, 10 or 20% of what? The tightest they could conceivably be compressed? Like by hand? With spanners ? Hydrolic press?

Secondly how would we define movable? Something that could be subject to some hammer like an inlet valve albeit with rigid piping? Or something on a flexi? Which surely by it's definition is constantly movable/flexible?

I used first couple over last few days. Both conical ones on tap connectors to float valves in toilets. Both were done up hand tight and then nipped up and remained leak free for 5-10 mins before leaving. When trying anything new you do wonder if you're leaving ticking time bombs everywhere but both were happy first time and even though that could be luck I suspect they will continue to be as they fit over the whole tap connetor end shape unlike many fibre washers that seem to leave a gap and weep when tight.

 

[Welder]

Apologies. 10-20% of their sectional area.

The definition of movable is indeed a 'movable' feast. This is where experience of the application kicks in. You do what is appropriate with the knowledge you have.