Blakes seacocks

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Hi Gang,

I have check through using the search facility and cannot see an answer. We bought a Westerly Konsort last year and I have just been servicing the seacocks. Whilst the body seems fine (hit with a hammer - sounds fine) the cone inside was very pink on the cone surface. Some of this has come off during grinding in the cones. Could this be de-zincification? Should I be concerned? Hope this first post is of a suitable nature!!!
 
Pink and crumbly sounds like dezincification, bin the entire vave and replace with new. Its the only way to get a decent nights sleep from now on!
 
Pink patches are a sign of dezincification and at
the ultimate degree it can lead to complete decay of the metal. THere are those on the forum who are qualified metallurgists who may give you a more comprehensive reply, but it sounds as if your Blakes have not reached the critical stage and from you say, the metal seems sound. All the same I would check your anti galvanic corrosion arrangements -- bonding, earthing etc, because galvanic corrosion can also attack props and sterngear. The condition of your sacrificial anodes will provide good evidence i.e. if they stay pristine they ain't working! If you spend a lot of time in the marina hooked up to shorepower, you might consider investing in a galvanic isolator, Merlin do a good one and it is an easy DIY fit.
 
I have found this to be quite common and it seem to me to be a surface phenomemenon on the cones. As you say it grinds out.
I would not give it a second thought. In fact I have been worried myself since I first observed it on my boat 15 years ago.
 
You are not really very clear here about the cone as you will see from the answers.

Did grinding remove just surface discolouration or did bits of the cone come off due to grinding action.

What does the cone sound like when you tap lightly with a small hammer or a spanner. This will give an indication of its condition.

If only surface discolouration then this can be polished off and the sea cock well greased on re assembly.. I use a copper filled type grease.
 
I've owned two boats with Blake's seacocks [5 years ownership of each] and although I've noted pinkish colouration I've never ground in any seacock so far and never had a problem with leakage - I simply dismantle annually, clean and regrease and then reassemble and adjust to be operable with one finger.
 
Many thanks for such quick responses - the surface didn't crumble off - just seemed to clean up when ground in. The surveyor said that both seacocks were servicable, but neither are bonded (we are on a swinging mooring in Mylor - where the boat has been since new). They sound fine when tapped with a hammer - so maybe I can stop worrying?
 
They are fine - a bit of pink is not uncommon but if it is only on the surface and they survive a tap with a hammer then worry no more. The important thing, as others have flagged is careful reassembly with the Blakes grease or similar and don't tighten down so as to squeeze all the grease out. Mine are 36 years old and still going strong. Bonding is not normally recommended nowadays unless there is a specific reason for doing it.
 
My Blakes are as old as the boat, 32 years. The boat only comes out every three years.

Yes there usually is some pink colouration but this goes away as soon as I start lapping the valve (what you are calling grinding). When the mating surfaces are uniformly lapped I rinse off all traces of paste with a diesel soaked rag, wipe clean and then apply Keenol or PBC grease and reassemble.

No, my Blakes are not bonded to anything else. I prefer it that way.
 
Two unbonded Blakes @30 years old (winters out of water). Slight pinkish, but both solid and slight grinding takes pink away. Its when you see cavities (spongelike) that you need to replace.
 
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