Stainless or regular Plated bolts to mount outboard.

[Alumarine]

Hi there.
I just had a new transom installed on my aluminum boat.
It's 1.5" of wood attached to the aluminum back.

I was wondering if I should use Stainless bolts or regular Plated bolts to mount my Merc 50.

I've heard that there might be a reaction between the stainless and the aluminum.

thanks

 

[lckstckn2smknbrls]

Re: Stainless or regular Plated bolts to mount outboard.

Stainless steel will have the least reaction with aluminum.

 

[metriccrescentwrench]

Re: Stainless or regular Plated bolts to mount outboard.

Here's a photo of a plated bolt I removed from my Checkmate in the process of restoring it. This bolt was used by a previous owner to mount the jackplate, and in fact was worse than it looks in the photo, it was rusted more than halfway through. If you're concerned about corrosion you can always add a zinc anode in good electrical contact with the hull, but I bet there's one already on your engine.

 

[foodfisher]

Re: Stainless or regular Plated bolts to mount outboard.

Anything you can do to seperate two dissimilar metals the better. Rubber washers, caulk etc.

 

[Mi duckdown]

Re: Stainless or regular Plated bolts to mount outboard.

Stainless, nut/bolt/and washers, and some silicone.

 

[5150abf]

Re: Stainless or regular Plated bolts to mount outboard.

Concur, had stainless bolts on mine forever and no problem with any reaction, that is all we use at work(Bennington) every nut bolt and washer is stainless and we don't have any problems.

 

[veritas honus]

Re: Stainless or regular Plated bolts to mount outboard.

Go with Stainless Steel. It's tried and true.

 

[Alumarine]

Re: Stainless or regular Plated bolts to mount outboard.

Thanks guys. Stainless it will be then, along with some 4200 sealant.
I think I'll replace the plated bolts that hold the new wood transom to the aluminum back end as well.

 

[Greg Mrozinski]

Re: Stainless or regular Plated bolts to mount outboard.

Marc,

Use 3M 5200 quick set formula instead of the 4200. It will hold up much better and form a more permenant seal.

 

[Alumarine]

Re: Stainless or regular Plated bolts to mount outboard.

Greg, I was thinking of the 4200 as I may be replacing the motor in the next year and was afraid the 5200 would be too permanent.

Marc,

Use 3M 5200 quick set formula instead of the 4200. It will hold up much better and form a more permenant seal.

 

[Greg Mrozinski]

Re: Stainless or regular Plated bolts to mount outboard.

Nah. You will be able to get the motor off fine and what 5200 remains you will be able to get off okay. Remember you don't need to use too much 5200 to seal the bolts/holes correctly. Besides the lower mounting holes will be at or below the waterline most of the time. Not good for 4200.