What do you make of this?

This topic has 13 replies, 9 voices, and was last updated 17 May 2016 at 00:25 by Sam Stones.

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16 May 2016 at 01:50 #24548
Sam Stones
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@samstones42903
Looking more like the Grand Canyon … close inspection produced this picture.
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16 May 2016 at 01:50 #238848
Sam Stones
Participant
@samstones42903
Here's a picture to ponder.

What could it be?

You can find more information from my `Leaking tap' album.

Sam
16 May 2016 at 02:15 #238850
Peter Krogh
Participant
@peterkrogh76576
I've seen that sort of thing before in cheap boat parts. We concluded it was an inclusion rolled into the tube (on one) and a bad seam in another. Never use brass on a boat, always bronze!

I've never seen a faucet fail like that. Wow.

Pete
16 May 2016 at 05:49 #238854
Tendor
Participant
@tendor
I suggest the type of corrosion called de-zincification. The zinc has been preferentially dissolved leaving the copper – hence the copper colour. The photo shows a similar failure in a garden tap fitting.

Rod.
16 May 2016 at 07:39 #238856
Michael Gilligan
Participant
@michaelgilligan61133
Excellent pictures and description, Sam

As Rod suggests; that is a 'textbook case' of dezincification … just compare your findings with this explanation:

**LINK**

MichaelG.
16 May 2016 at 08:46 #238861
Martin King 2
Participant
@martinking2
Toatlly agree it is dezinced.

I used to do an awful lot of diving on old wrecks and whenever we lifted a piece of 'salvage' or more properly a trophy , there was often extensive evidence of this phenomena, sometimes so bad that the item fractured completely. I once got a porthole where the 1/4 thick rim was just a pink copper spiders web.

Martin
16 May 2016 at 08:57 #238862
Neil Wyatt
Moderator
@neilwyatt
It's a bit late for me to suggest de-zincification, isn't it…

N.
16 May 2016 at 10:57 #238887
Sam Stones
Participant
@samstones42903
Gentlemen all,

How very enlightening. Your comments are most appreciated. Everything fits in with de-zincification.

Here’s more of the background:

Having seen (and used) numerous brass plumbing fitting etc., I have always imagined that (especially) taps were only ever cast. Not so, it seems; but please read on.

It was necessary to replace the kitchen mixer-tap after it began to leak (from the barrel section) more than three years ago.

A few weeks ago, a tiny white spot appeared on the chromed surface of the stem of the replacement. The spot stubbornly refused to budge when wiped with a cloth. Closer inspection showed that the spot was actually weeping drops of water. For a while, it remained simply a `point’ of interest.

In the past week or two, tiny jets of water began to appear underneath the tap. See pictures 1 and 2. It was therefore necessary to replace the tap, which we did.

Being a rather inquisitive creature, I attacked the tap with a hacksaw (as you would), cutting away the offending section. To my surprise, I discovered that it wasn’t cast after all, but thin brass only 0.6mm (0.025&rdquo thick. See picture 3.

It seemed that this section of the stem had split. It also appeared to have been extruded before being flattened into an elliptical profile. I now wonder whether there is either a crack or lines which have been overly stressed. Pictures 4 and 5 show in close up, the outside and inside surfaces respectively.

Pictures 6 and 7 were taken after I rubbed away some of the surface.

The right hand edge in Picture 6, shows three layers; brass, copper, and chrome. From my limited knowledge, this appeared to be the correct approach to chrome plating.

Would additional zinc (>15%) in the brass be there for a cost reduction, or would it make forming and shaping etc., easier?

Interesting!?

Regards,

Sam

Addendum – After heavy rain and on other occasions, Melbourne's water smells strongly of chlorine.

Hmmmm
16 May 2016 at 11:03 #238890
Sam Stones
Participant
@samstones42903
PPS – I've no idea how the winky icon got into my last post. The line was supposed to read –

To my surprise, I discovered that it wasn’t cast after all, but thin brass only 0.6mm (0.025&quot thick.

I look forward to more helpful comments.
16 May 2016 at 11:05 #238892
Sam Stones
Participant
@samstones42903
Same again!!!

What a bugger!!! Must be the brackets ))))))
16 May 2016 at 11:30 #238898
Hopper
Participant
@hopper
Cheap Chinese junk strikes again. A bit of tin in the brass will retard de-zincification, but costs more money, dunnit.

The cheap Chinese copper water pipe sold today is no better. It develops pinholes after about 10 years of use. Usually inside a wall cavity. Usually next to a carpeted room. Usually while you are away on holidays for a month. Ask me how I know this.

Best one so far is the house wiring cable sold in Australia in recent years. Thousands of kilometres of it. Used to wire tens of thousands of new houses. Now, after just a few years, the insulation is cracking and falling off. Turns out the insulation was made from recycled plastic to save costs. But recycled plastic is not as strong or durable as the newstuff. All this despite the cable's being labelled to meet Australian Standards. I guess nobody checks these things anymore.
16 May 2016 at 12:06 #238911
Danny M2Z
Participant
@dannym2z
Posted by Hopper on 16/05/2016 11:30:18:

Best one so far is the house wiring cable sold in Australia in recent years. Thousands of kilometres of it. Used to wire tens of thousands of new houses. Now, after just a few years, the insulation is cracking and falling off. Turns out the insulation was made from recycled plastic to save costs. But recycled plastic is not as strong or durable as the newstuff. All this despite the cable's being labelled to meet Australian Standards. I guess nobody checks these things anymore.

I read that this has caused a few house fires already and is being investigated by the ACCC **LINK**

Does 'C Tick' really mean China Compliant?

* Danny M *
16 May 2016 at 12:32 #238915
Martin 100
Participant
@martin100
I've seen this on a stopcock under the sink in a relatives house although all that happened was internal. I came to do some minor plumbing work but couldn't move the valve one way or the other. Last time it was operated was maybe 20 years earlier with a kitchen refit, the valve maybe predating that by another decade.

I slackened off the gland, introduced some penetrating fluid, still no joy. So I went upstream and then found the water board stopcock at the boundary was also seized. After that was replaced, (it was apparently done 'live', but required a revisit for a leak on a compression joint) I could finally tackle the stopcock in the house. After replacing it. I put the old one in the vice and took it apart with a bit of heat and a birmingham screwdriver. When in bits the threads, the valve faces and all the internals in contact with the water were pink, just like pickled copper. The threads eroding away to nothing. Externally the valve looked perfect and not much metal appeared to have been lost from the valve body.
17 May 2016 at 00:25 #238989
Sam Stones
Participant
@samstones42903
[Danny wrote – I read that this has caused a few house fires already and is being investigated by the ACCC **LINK**]

It makes one wonder Danny, especially after the Pink Batts saga – **LINK**

In case you didn't examine my album, this is the scale of the Grand Canyon inside the tap.

Once again chaps, thank you all for your contributions.

Regards,

Sam

Edited By Sam Stones on 17/05/2016 00:26:17
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