G
Guest
Guest
I have just bought a new heads for my mirage 26, seacock & skin fittings came as a kit. The skin fittings are brass & the sea cocks are stainless, are these going to be ok together? Any help appreciated.
steve_cronin
N/A
Many boats have this combination and have floated for years. Just bond everything together and to the skin anode(s) with 6mm cable. Also use PTFE tape when you screw the valves on to the skin fittings. Not against corrosion but just to stop weeping along the threads.
Steve Cronin
Steve Cronin
PuffTheMagicDragon
Active member
They would be O.K. if the fittings are made of BRONZE. If, as the original poster said, they're made of BRASS, I would'nt have them anywhere on my boat that's permanently underwater.
Fair Winds!
Wally
Fair Winds!
Wally
AndrewB
Well-known member
OK - but not ideal.
It depends a good bit on what grade of stainless and the quality of brass you are using. Most stainless steels are close to brass in the gavanic order, so electrolysis will be slow, but some brass fittings (notably imported from Italy and elsewhere) are of quite inferior grade and erode fast.
Many grades of stainless steel will corrode (also very slowly) if they are starved of oxygen, and so stainless is normally avoided in fittings that are permanently underwater.
So you will need to watch out for: (i) de-zincing of the brass. The brass goes a coppery colour and crumbly. If this is a heads fitting beware, excreta seems to accelerate this; (ii) pitting of the stainless steel, particularly where it is in contact with brass and underwater. I wouldn't expect much problem at first, but after 3 years these fittings should be dismantled and checked.
All bronze fittings would be a good replacement in due course.
PS are you sure the seacocks are stainless and not chrome plated brass?
It depends a good bit on what grade of stainless and the quality of brass you are using. Most stainless steels are close to brass in the gavanic order, so electrolysis will be slow, but some brass fittings (notably imported from Italy and elsewhere) are of quite inferior grade and erode fast.
Many grades of stainless steel will corrode (also very slowly) if they are starved of oxygen, and so stainless is normally avoided in fittings that are permanently underwater.
So you will need to watch out for: (i) de-zincing of the brass. The brass goes a coppery colour and crumbly. If this is a heads fitting beware, excreta seems to accelerate this; (ii) pitting of the stainless steel, particularly where it is in contact with brass and underwater. I wouldn't expect much problem at first, but after 3 years these fittings should be dismantled and checked.
All bronze fittings would be a good replacement in due course.
PS are you sure the seacocks are stainless and not chrome plated brass?
G
Guest
Guest
Re: OK - but not ideal.
thanks for the advice, much appreciated. Threads on inside of seacock are also silver coloured, suggesting fitting is stainless, not plated brass. julie.
thanks for the advice, much appreciated. Threads on inside of seacock are also silver coloured, suggesting fitting is stainless, not plated brass. julie.
