Monobloc flexi tail

[Tim Watts]

Just had the worktop in the kitchen installed:

Unfortunately the chap doing that managed to get a very bad twisted kink in one of the tap tails - easily done, when it's hard to see...

I've redone the joint to it is unkinked, but it feels a tad weakened in the area that was kinked.

Anyway, I'm inclined to replace it for my peace of mind as it carries hot water at full mains pressure and it is nether a difficult nor expensive part.

But just out of interest, is it really likely to have weakened it? Garden hoses once kinked seem to favour kinking again at the same spot - and I'm not even sure what the tube is made of in these tails - rubber or something exotic?

2nd Q: with monoblock tails the tap end has a rubber O ring - is it usual to grease these with plumber's grease before inserting or just use them as they come from the packet?

Ta

Tim

[Andrew Gabriel]

Grease them with clear silicone grease - helps the O-ring to go in without getting distorted into the wrong position. (Ideally you use food grade silicone grease, which is available from BES for this purpose.)

[Tim Watts]

Thank you Andrew - I will see what my grease looks like. Pretty sure it's silicone (it is plumbers grease). Might not be potable (or food) rated though - I bought it originally for waste pipe joints (anything that had rubber in) - I'll check.

[Tim Watts]

Two more things:

I see there are M10 and M12 tails (8mm and 10mm bore). How do I tell which one I have?

The other weird thing is:

Mine are 1/2"BSP female with end seal washer to mate with my pipework (copper that ends with 1/2" BSP male brass).

These seem to be non existant in Screwfix, Toolstation and even BES[1]

And yet, ebay is full of them:

(Mine are 300mm long ish).

[1] Though I notice:

Item 21627

Stainless corrugated. Wonder if those are rated as more durable than flexi tails?

But it's weird that even BES don't have BSP female - mostly 15mm compression.

[Tim Watts]

Is corrugated stainless less susceptible to the problem of work hardening that might affect corrugated copper?

[Andrew Gabriel]

I suspect the M10 thread is 10mm diameter, and M12 is 12mm diameter.

Yes, it's basically a 1/2" tap connector the wrong way around. I've recently fitted a wash basin monoblock using tails with

1/2" male to connect to the pipework (I discarded the copper pipt tails with came with the monoblock).

The thread on 15mm compression is usually near enough to mate with

1/2" BSP. That doesn't mean your female connector will seal against a 15mm compression fitting, but it might be worth a try - would be handy if it sealed against one side of a 15mm-15mm isolating valve.

[John Rumm]

[newshound]

A bit difficult to answer. What's going to kill both of them is multiple reverse (plastic) bends in the same area, for one or two cycles which are not too severe either would probably be OK.

Going back to your braided stainless over rubber tube, the combination of internal pressure and external braiding will straighten out the original kink when you correct the geometry. Provided it has not been kinked for any length of time I would expect it to show no long term problem. If it is kinked for a long time, rubber degrades in the highly stressed region in the presence of ozone, UV, or slightly incompatible chemicals. In your case of course none of these *should* be present apart perhaps from organic contamination on the outside of the braid (non silicone grease, flux?).

[Tim Watts]

I know copper fractures very easily if subjected to repeated deforming vibrations - and I guess a corrugated pipe will shake due to hammer.

The corrugated stainless is marked "new" in BES, so I'm wondering if it really is a good idea or whether in a few years, it will be discovered to be failing all over the place.

Gas meters often have corrugated pipes but gas doesn't have hammer (well if it did you've got bigger problems).

Turns out the chap has a spare pair so no problems - he's as big a perfectionist as me, so was quite happy to change them and apologised for not noticing the kink.

I usually do my own plumbing but here I'd provided copper ends with 1/2" BSP male threads in brass and he added the tap as he did the worktop.

Must put a photo up of that - he's done a lovely job - worktop is pitch pine which looks super and should be very resistant to water (it's coated with Liberon Finishing Oil too, 4 coats) whilst maintaining the benefits of wood (kind to glasses and crocks, can be sanded if damaged).

Apparently you can't obtain it easily in this country (except as rough lumber for crates) - he imported his own container load from Honduras as it's become his recommended wood for worktops if the customer wants wood.

Need to get some tiles and wall paint up and wire the cooker, then that job is done! Just leaves the shower room round the back and the upstairs dormer to fix...