aluminium anodes....salt water?

[seventeen2]

please couls anyone offer assistance?
I have been trying to locate zinc anode kits or my volvo sx outdrives, but al that seem to be on offer are alminium types?
These claim to be perfectly safe to use in salt water, ant ideas?
Cheers

 

[VicS]

Zinc or aluminium are suitable for salt water

Aluminium for brackish water

Magnesium for fresh water.

See here

The aluminium anodes are said to last up to 30% longer and they are cheaper.

 

[Frontier]

My boat was eating anodes so I tried aluminium, but then realised they are made out of the same stuff you are trying to protect. So although they lasted I got concerned for the legs, and the props suffered badly.

So I went back to zinc and fitted a galvanic isolator. Now the anodes seem to last and no other problems.

Try McDuff for anodes they should have all types, or even Ebay but cant vouch for the purity on ebay.

Good luck

D

 

[VicS]

[ QUOTE ]
but then realised they are made out of the same stuff you are trying to protect.

[/ QUOTE ] No they are not. They are made of an alloy which gives the same, or slightly better, level of protection as zinc anodes.

Relative to a silver/silver chloride reference electrode they typically have a potential of -1.09 volts compared with -1.05 volts for zinc anodes.

A galvanic isolator is almost essential if you leave the shore power lead connected.