Have I turned my windscreen into a giant anode?

[QBhoy]

Hi all,
Just today I have had a new stainless steel framework adjusted and installed onto my wrap around wind screen on my bowrider speedboat. I didn't pay too much attention at the time, but I'm now sitting here wondering if the windscreen is Aluminium and I've just had a stainless steel frame screwed into it. You can see where I'm going with this....will there likely be a galvanic reaction and has anyone had any experience of windscreens degrading because of this ? I'm not too up to date with my periodic table and metallurgy references, but might it be ok because Aluminium usually struggles to rust ? On the other hand, anodes are occasionally made of Aluminium and they obviously just disintegrate !!
All opinions welcome...

 

[QBhoy]

Sorry, should add that the frame work is for a hood.

 

[[2068]]

It might corrode eventually, but the thing about dissimilar metals is more about what happens when they are all in electrical contact, with a path for them to act as anodes and cathodes, e.g. underwater.
If you moor your boat upside down, this could be a problem

 

[QBhoy]

Haha.
Yeah, you are probably right. It was up the right way when I left it...hopefully stays that way ?

 

[CLB]

You need an electrolyte for galvanic corrosion. You may get very local corrosion from spray or rain water but stainless bolts into aluminium is a recipe for disaster anyway.

 

[Tranona]

If you are attaching stainless to aluminium or using stainless fastenings into aluminium, then coat the mating surfaces with duralec which is a paste that isolates the two and reduces the chances of corrosion. Used for example by riggers when attaching stainless fittings to aluminium masts. Also useful where stainless screws are used in aluminium castings such as some windlasses.

 

[QBhoy]

Good advice all
Tranona, you reckon copaslip (molycote product) do the same job ?

 

[prof pat pending]

Copaslip is rather good on battery terminals, so no, I'm afraid it won't work well in that application

 

[Momac]

A gasket between the two metals and inspect regularly for any signs of corrosion.
I am sure my last boat has stainless lift the dot pins in its painted aluminium windscreen frame together with a couple of screw fixings - and no serious issues.

 

[CX54WEK]

A gasket between the two metals and inspect regularly for any signs of corrosion.
I am sure my last boat has stainless lift the dot pins in its painted aluminium windscreen frame together with a couple of screw fixings - and no serious issues.

You remember correctly. The S23 has stainless canopy fastenings on the aluminium window frames.

Ours is just starting to get very slight corrosion around the front fastenings which are the ones most prone to getting salt spray. Nothing out of the ordinary for a 13 year old boat though.

 

[QBhoy]

Thanks Guys, I'll try that coating and a rubber gasket.