Stainless steel and aluminum

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fowlmood77

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I have a question about using stainless screws on an aluminum hull. I have done it before but haven't seen the long term results. Supposively it will cause corrosion. What is everyones opinion on this? What is everyone using to secure flooring to the ribs? So far this is what I have come up with during my search for answers. Kinda goes both ways.


1. ...Contrary to what most people think Stainless steel screws do not cause corrosion in aluminum it is the minute gap around the screw subject to friction caused by flexing that promotes the corrosion If you were to use the same alloy alum. screws you could witness it yourself That is why the boats are riveted.

2. ...Another potential corrosion trouble spot is wherever two dissimilar metals meet. For example, corrosion will form where stainless screws are set in aluminum. Treating both metals with a product called Tef-Gel will keep this from happening.

(of course this was referring to a saltwater boat)

3. ...Remember that aluminum and stainless steel will lock together permanently in a very brief time, so when you're ready to make the final installation use a very high grade anti-seize compound on the screws
 
Though they are dissimilar metals, they aren't far from each other. I used to have a handy little graph that showed this extremely well, but I cannot find it. Stainless and aluminum are fairly close to each other, so the only real concern would be if the stuff was going to be submerged for long periods of time in salt water (by long periods of time, I am talking months, not what your average saltwater fishing boat or aluminum trailer would see). The only alternative would be to use aluminum fasteners, and though some aluminum bolts exist, the only practical aluminum fastening method is going to be rivets. I wouldn't even bother with an anti seize compound.

Now, galvanized bolts are a big no no, as is copper, and pressure treated wood. They are rather far from each other on the aforementioned graph, and you will see the corrosion within a matter of months.
 
you can look for a product called "never seize" it is great I use it on my lug nuts to prevent them from rusting
Wayne
 
bassboy1 said:
Though they are dissimilar metals, they aren't far from each other. I used to have a handy little graph that showed this extremely well, but I cannot find it. Stainless and aluminum are fairly close to each other, so the only real concern would be if the stuff was going to be submerged for long periods of time in salt water (by long periods of time, I am talking months, not what your average saltwater fishing boat or aluminum trailer would see). The only alternative would be to use aluminum fasteners, and though some aluminum bolts exist, the only practical aluminum fastening method is going to be rivets. I wouldn't even bother with an anti seize compound.

Now, galvanized bolts are a big no no, as is copper, and pressure treated wood. They are rather far from each other on the aforementioned graph, and you will see the corrosion within a matter of months.



Agreed you will need to replace the decking again before you need to worry about useing stainless with aluminum
 
Thanks guys. Guess I can keep on doin what I have done in the past without worry. Got to replace the transom in one boat this summer and am going to have to cut out some rivets. Plan on going back with silicon and ss screws and bolts.
 

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