Alloy boats and dissimilar metals

I'm doing a bit of work on the boat that required more fixtures, wondering what others do to prevent dissimilar metals causing electrolysis i.e stainless bolts, I'm sure a few on here will have had a bit of experience with this stuff.

I made plastic bushings for where S/S bolts went through the aluminium. For things like the transducer screws into the transducer bracket, I greased them, and removed and clean each year.
Be sure not to use any copper or brass fittings directly against the aluminium.

I'll be painting holes where can't get plastic washers in, hoping that's enough to prevent issues

We used a Teflon Gel (barrier) that was applied with a paint brush that basically eliminated any galvanic issues.
Might pay to see if something is available at a marine shop!?
SS and aluminium are reasonably compatible.
It's the alloying ingredients (alloy's) in the aluminium/SS that exacerbates issues.

The salts just as bad

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Originally Posted by Fireflite

We used a Teflon Gel (barrier) that was applied with a paint brush that basically eliminated any galvanic issues.
Might pay to see if something is available at a marine shop!?
SS and aluminium are reasonably compatible.
It's the alloying ingredients (alloy's) in the aluminium/SS that exacerbates issues.

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@Fireflite. I think we used a similar product when I was marine in the US. It was a product called Tef-gel. It is absolutely awesome. Lots of S/S fittings into aluminium were coated in this This stuff

I just used a layer of silicon gell between the stainless washer and any alloy

copper cote?

Def not coppercote!

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Originally Posted by kiwijames

@Fireflite. I think we used a similar product when I was marine in the US. It was a product called Tef-gel. It is absolutely awesome. Lots of S/S fittings into aluminium were coated in this This stuff

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Thanks for that I see jaycar are local stockists

Berg243 has the berries

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Originally Posted by Markgibsonr25

copper cote?

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NOOOOO

don't add copper coat if you have aluminum alloy.

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Originally Posted by Markgibsonr25

copper cote?

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Break a mercury thermometer in the bottom to. ...... :)

No don't use anything with copper in it as a barrier agent.

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Originally Posted by Beaker

Break a mercury thermometer in the bottom to. ...... :)

No don't use anything with copper in it as a barrier agent.

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Mercury is total death, you can watch it eat the aluminum before your eyes. Have never forgotton watching it as a science project. Drop of mercury on a sheet of aluminum within a minute white "feathers" of aluminim oxide poke out of the mercury and just keep growing and growing. Teacher wipes the mercury off and where he wiped grows a forest of white plumes.

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Originally Posted by Marty Henry

Mercury is total death, you can watch it eat the aluminum before your eyes. Have never forgotton watching it as a science project. Drop of mercury on a sheet of aluminum within a minute white "feathers" of aluminim oxide poke out of the mercury and just keep growing and growing. Teacher wipes the mercury off and where he wiped grows a forest of white plumes.

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It's a very impressive reaction for sure.

duralac is good for screws and rivets it's not cheap....DURALAC

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Originally Posted by Markgibsonr25

copper cote?

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Never!!!!

copper and alloy is the devil !

Total isolation is always the best solution from a corrosion perspective but not always practical.
next best is excluding h2O and O.
Never use a copper type neversieze on alloy or near alloy components, it will cause the alloy to corrode.

back in the day I used to use a green paste similar to shelac for bolting ss fasteners into cast aluminium and it was the ducks nuts....unfortunately I forget the brand at the mo.

to give you an idea of copper and alloy together. as a kid i powered a small radio from using copper and aluminium plats stuck in a lemon !