Brass - bronze - Stainless steel - fittings

[BartW]

Have been doing some refurbish work on one old toilet flushing pump
and replaced a 1,5" one way valve.
I bought this Check valve and a few extra fittings from a Belgium "water systems parts shop" nothing todo with marine, nor seawater,

I didn't give this attention when I bought them, but realise that these parts material is "messing"
the Original fittings on our Canados might be bronze ? or "Corrosion Resistant Brass " (?)

the Original fittings and the pump have been filled with seawater the past 25 years, I guess they have been cleaned before my time, (+7y ago) but the fittings and the pumps are in amazingly good condition.

how can one see the difference between messing, brass or bronze ?
is messing good enough for seawater ?

a few years ago I have replaced my airco primary cirquit seawater pump with a stainless steel model (purchased from a local pump shop in France, not for marine)
so how about stainless steel for sea water.

I'm not sure if or when the seacocks on our boat have been replaced,
afaik they have'nt the last 9 years.
Is it ok to check them during liftout; slightly grind them and sheck if the bronze (?) is still glossy ( inside aswell as outside) and no trace of corrosion,
Or should they be replaced preventive anyway ?

 

[kashurst]

I think messing is German for brass. You can use brass with seawater but if it is connected to a different metal it will erode. The zinc will come out of it and it will go brittle unless there is a anode connected. So for a few years it will be ok as long as there is a seacock before it just in case. Bronze would be better but not always available.

Stainless is ok with seawater too, but again it depends what it is connected to, so again needs care. Also it can suffers from crevice corrosion on the threaded parts.

You can check your seacocks by doing what you describe, scrape/sand/grind away the surface paint and see if it's nice and shiny. Any pink bits and its replacement time.

 

[Bouba]

Hi Bart, I notice that there is not a lot of response to this vital issue. If you go to the trawler forum you will find that this is taken very seriously and lots has been written, they have one uber expert on the subject and he is very generous with his knowledge. Hope this helps

 

[Bandit]

Look at Vic-S of this parish and his good website : http://coxengineering.sharepoint.com/Pages/Metallurgy.aspx

Underwater use DZR, if you don't know what it is or it is Brass bin it and buy DZR.

Brass can last 5 to 7 years but if you have an anode problem or a connectivity problem or an electrical earth leak you loose the zinc from the brass alloy it goes pink , it becomes porous and it will crumble or shear off this could happen very quickly with an electrical problem.

Stainless steel pipes underwater, for skin fittings, valves and bends is not good it creates as many problems as its solves, Back to DZR.

 

[BartW]

thank you for the few, but very informative answers,
lesson learned; only order fittings from my favourite specialised marine technical supplier in Fiumicino (Italy) : Ceresoli
this is a supplier to all yards and boat factory's in the Rome region, (ao Canados )
they have a seperate chapter of Corrosion Resistant fittings in their catalog,
many of these fittings have the FG logo (Guidi brand)
(no connection, just a regular happy customer for anodes and stuff)

regarding Blue Angel seacock's;
yes a thorrow checkup is required during next liftout,
outside aswell as inside !

thanks for taking time to give advice !
cheers,
Bart.

 

[vas]

Bart,

you could also consider GRP skin fittings.

Marelon or Trudesign?

I've only got glass reinforced plastic fittings on MiToS (NZ Trudesign), no need for bonding and messing with cables, v.smooth operation and extremely robust (when I had to cut/break/remove a 1/2inch took me a surprising amount of time with a hammer and a chisel!)

I'd not use SS anywhere below w/l and I'm always afraid on whether something sold as DZR is actually that or someone is making a huge profit and you're buying a liability...

cheers

V.

 

[Portofino]

I had all 7 replaced last year by a yard I think DZR
Boat 2001 -3 were ceased-( never excercised ) - unsure of age . condition was good
Just piece of mind . Now I have a paper trail . Just kinda thought about most likely insurance claim and if there was anything I could do to mitigate a leak / sinking .
Also had all " black " unmarked ER water piping and hose clamps replaced , with Vetus CEO marked ISO ? Exhaust grade piping . Seacock to strainer , strainers to engine water pump , engine to HE , s -gearbox coolers - to exhaust - etc all of it .

Again no specific sell by date or obvious wear to go by except time .

Thing about an old boat or a new boat to you that ages - from say 5-7 or 10 y +
When do you start on the merry go round of replace / renew / update of seeming perfectly in the sense of " if it ain't broke don't fix it "

Sea cocks all excercised now btw.

Like most I have a "man maths " annual spend for upkeep .