Copper and aluminium

[badman]

Does anybody know which metal is suitable for use next to aluminium as a gasket..?
I have seen copper used but i beleive copper is too far away from Aluminium in the chemical chart and causes degradation / chemical reaction.

Cheers
p.s. water cooled manifolds fabricated nicely at www.moorcroftengineering.com

Did a good job on mine.

 

[Bondo]

Re: Copper and aluminium

as a gasket..?

Ayuh,... A Composite gasket would be Best...

Are you going to be running this in Sweetwater, or Saltwater,..??

 

[Rickairmedic]

Re: Copper and aluminium

Copper and aluminum get along just fine together most of the airconditioning coils in this country are made with copper tubes and aluminum fins and the only adverse problems are the galvanised endcaps that rust and cause problems with the copper .


Rick

 

[North Beach]

Re: Copper and aluminium

No problems joining copper and aluminum whatsoever!

 

[Bob_VT]

Re: Copper and aluminium

What is the purpose of this gasket? Between what surfaces? Where will it be used?

 

[Silver Heels]

Re: Copper and aluminium

Isn't it the copper in pressure treated wood that reacts with with aluminum causing corrosion?

 

[Ned L]

Re: Copper and aluminium

Badman is completely correct, copper & aluminum are pretty far apart on the galvanic scale. Put the two together & immurse them in an electrolyte (salt water), you create a battery, and the aluminum is corroded away. In this case, (I'm guessing it might be a manifold gasket), these is no (or minimal) electrolyte involved, so chances are good that there would be no issue. However best bet would be a composite gasket (as has been suggested).

The issue of how to deal with (and fasten) aluminum on commercial boats & ships is a real issue. There are all sorts of precautions taken, esp. when fastening aluminum structures with S.S. fastenings, lots of plastic bushings & washers can be involved.

 

[badman]

Re: Copper and aluminium

hey. thanks for the replies folks.
the gasket is to go between a steel (manifold paint applied) manifold and a thick plate of aluminium.
The previous owner had a copper gasket which had severely corroded the aluminium and the old steel manifold (box section).
My re fabricated mani's currently have zinc coated manifold gasket in between them and the ali plate but i don't know ho this will last or handle.
If my welding and measurements are good enough there should be little to no salt water entering the area.
However, there will always be salt spray and salt in the air etc.

On the water side of the manifolds is a stream of pumped water which the stern drive allows to cool the main exhaust casing of the drive (transom area).
This will be salt water and will be in close proximity.

Cheers and yes, the combination of metals in boats is a tricky one!
badman

 

[Bob_VT]

Re: Copper and aluminium

build them up and reface them with a sander. I would then use good old standard gasket material and avoid metal all together.

 

[ImNu2Boats]

Re: Copper and aluminium

hey. thanks for the replies folks.
the gasket is to go between a steel (manifold paint applied) manifold and a thick plate of aluminium.
The previous owner had a copper gasket which had severely corroded the aluminium and the old steel manifold (box section).
My re fabricated mani's currently have zinc coated manifold gasket in between them and the ali plate but i don't know ho this will last or handle.
If my welding and measurements are good enough there should be little to no salt water entering the area.
However, there will always be salt spray and salt in the air etc.

On the water side of the manifolds is a stream of pumped water which the stern drive allows to cool the main exhaust casing of the drive (transom area).
This will be salt water and will be in close proximity.

Cheers and yes, the combination of metals in boats is a tricky one!
badman

I'm pretty new here but I did spend a few years aboard Ship as a Communicatins Officer and we always used zinc anti-sieze on stainless steel fastners whenever we needed to secure aluminum to steel.

Don't they also put sacraficial zinc plates on aluminum outboards.

 

[badman]

Re: Copper and aluminium

uhhuh. yep, got a sacrificial plate on the back which should help!
zinc seems to be mentioned quite a lot as a beneficial metal.
cheers

 

[Bondo]

Re: Copper and aluminium

the gasket is to go between a steel (manifold paint applied) manifold and a thick plate of aluminium.
The previous owner had a copper gasket which had severely corroded the aluminium and the old steel manifold (box section).

Ayuh,... Is this the motor end of the manifold, or the drive end of the manifold,..??
I think I remember your unique little barge, with it's equally unique Powerplant...
If so,...
Did you pattern the New manifolds by the Old, or start Fresh,..??

 

[wca_tim]

Re: Copper and aluminium

Could send the aluminum plate off to be hard anodized... very corrosion resistant and non conductive (no galvanic corrosion...)

 

[badman]

Re: Copper and aluminium

Ayuh,... Is this the motor end of the manifold, or the drive end of the manifold,..??
I think I remember your unique little barge, with it's equally unique Powerplant...
If so,...
Did you pattern the New manifolds by the Old, or start Fresh,..??

Hi there.
Remade the manifolds following the original design but modified the design slightly so that my mani's are 3 part rather than 2.
That way i could guarantee a better fit and seal on the bizarre mounting plate on the stern drive by mounting mani box section 3 onto it with gasket, then the engine with mani's 1 and 2 bolted on swings in to meet it etc.
There's a few pictures attached.
cheers

 

[Bondo]

Re: Copper and aluminium

Ayuh,... Simply Amazing......