Eek! Quality Seacock fittings on a Jeanneau...

vyv_cox said:
DZR (dezincification resistant brass) is somewhat cheaper than bronze and an effective substitute. Unfortunately it is not easy to tell whether what you are being sold is actually this material, so be careful.
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That's the problem. Customers assume that as it's in a chandlers it must be the correct material - not true as many chandlers sell brass fittings. I buy from EC Smith who have a choice of DZR or bronze - http://www.ecs-marine-equipment.co.uk/marine-search/exact/bronze-ball-valve.html
 
GrahamM376 said:
That's the problem. Customers assume that as it's in a chandlers it must be the correct material - not true as many chandlers sell brass fittings. I buy from EC Smith who have a choice of DZR or bronze - http://www.ecs-marine-equipment.co.uk/marine-search/exact/bronze-ball-valve.html
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It's easy with the valve, which will normally be marked up with the material of construction (although note that ECS carefully avoid saying that the ball is bronze, which it probably is not). When it comes to skin fittings, elbows, hose tails etc there is no marking.

I have been told by a chandler that Tonval is ideal for underwater use and his display was proudly marked up with that name. In fact Tonval is a leaded brass that was directly linked to the Random Harvest sinking.
 
re Vyv's post #46:
it's well worth reading the Random Harvest report: http://www.maib.gov.uk/cms_resources.cfm?file=/random harvest.pdf

About Tonval, it has this to say:
The trade name Tonval, in the UK, conceals rather than conveys the nature of the material used for the through-hull fittings. To ensure that buyers of these products are fully aware of the nature of the material, such fittings should be
clearly described as made of a “brass (not inhibited against dezincification)”.
(Reassuring to see that that's happened.)

Amongst the conclusions:
4. The brass through-hull fittings removed from Random Harvest did not meet the requirements of the international standard for metallic seacocks and through-hull fittings on small craft, ISO 9093-1:1994.

6. The guidance offered on the selection of corrosion-resistant material in ISO 9093- 1: 1994, Small craft - Seacocks and
through-hull fittings, is vague and of little practical help.

11. Both ECS and Sowester had mistakenly described the materials for their through-hull fittings as bronze.
(The precise source of the failed fitting was never discovered but was narrowed down to just a few suppliers.)

Cause of accident: Random Harvest flooded because of the failure of a through-hull fitting, installed 16 months before.

P.S.: you can get a copy of ISO 9093-1:1994, here: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=16682
Unfortunately it'll set you back 50 Swiss Francs.
 
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vyv_cox said:
DZR did start as a British Standard to combat dezincification in soft waters in the UK but it is now an International standard material CZ132. It is pretty much as resistant as bronze but only slightly more expensive than brass. Blakes seacocks, often held to be one of the better ones, have been made from DZR for about 25 years. Mine are that old with no dezincification at all.
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so I have a question, just curious: what do You think about putting new DZR valves onto bronze through-hulls, and then screwing bronze connection on them?
In one case this would be bronze skin fitting, then DZR valve, then bronze engine strainer directly screwed on, followed by bronze oil cooler for transmission, followed by copper tubing to copper heat exchanger... This one I will probably leave alone for time being; 40 years gate type but working - and seems to have connection somehow to engine and anode, got to sort it out... :o
 
Troubadour said:
I've added some more photos - inc one of the engine seacock which is not black - from which you can see that all the nuts have flanges and they are not plastic.
The flanges are black where they are not covered with Sikaflex, it's not paint on the Sikaflex.
Most of the odd black stripes on the plated valves appear to be black marker pen where they are not just dirty gunge.
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some of your flanged nuts appear to be ferrous to me. The black coating on some of the nuts looks similiar to some of the rust convertor products I've used in the past.
 
vyv_cox said:
I think the risk of galvanic corrosion is probably low. The voltage between all the copper-based alloys, brasses and bronzes, is a very small range, less than 0.1 volt in most tables.
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So I thought, and putting them on to have new. What's interesting - would the zinc in there still be "Dezincification resistant"? will see :)
Old bronzes serviced and kept, all but one look perfect. At least valves are easy to replace, even underway; not so with skin fittings...
 
cimo said:
some of your flanged nuts appear to be ferrous to me. The black coating on some of the nuts looks similiar to some of the rust convertor products I've used in the past.
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Interesting idea that I hope even Jeanneau wouldn't use but I will check on Sunday!
 
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