I have found that my through the hulls are two different metals for intake and output through hulls for my head; I'm a new owner to this older Catalina 27. One metal is stainless steel and the other is brass; will I have an electolysis problem with this set up?
Two different metals at through hull - problems?
- Thread starter rsn48
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YES, but......
When ever any metals come in contact with an electrically condutive path( sea water) you have a corrosion cell (rust) which in effect becomes a battery. This is normal. In your case the electrically conductive path would be the sea water. The stainless steel usually is higher up on the galvanic scale than the brass. This means that the stainless steel becomes the Positive terminal and the brass becomes the negative terminal.So now the electrons and ions flow from negative to positive, which would be from the brass to the stainless steel. What does this mean...the brass would deteriorate or rust faster than the stainless steel. The good news is that they are both somewhat resistant to corrosion and will last a fairly long time and also the zincs that you put on your prop shaft will also lose these little particles to both the steel and brass. Since you can not eliminate the corrosion completely, i wouldnt be concerned especially if they are not in direct contact with each other.
When ever any metals come in contact with an electrically condutive path( sea water) you have a corrosion cell (rust) which in effect becomes a battery. This is normal. In your case the electrically conductive path would be the sea water. The stainless steel usually is higher up on the galvanic scale than the brass. This means that the stainless steel becomes the Positive terminal and the brass becomes the negative terminal.So now the electrons and ions flow from negative to positive, which would be from the brass to the stainless steel. What does this mean...the brass would deteriorate or rust faster than the stainless steel. The good news is that they are both somewhat resistant to corrosion and will last a fairly long time and also the zincs that you put on your prop shaft will also lose these little particles to both the steel and brass. Since you can not eliminate the corrosion completely, i wouldnt be concerned especially if they are not in direct contact with each other.
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