Corrosion

[bazz]

Hello to everyone from Ausfish. Been a wet and windy week end but time to do a bit of a clean up.I have just washed my Stacer runabout and noticed what appears to be the beginning of a bit of corrosion around the side curtains press studs that fasten the curtains to the deck.
They are stainless steel as most of them are and I am aware that dissimilar metals such as these can and generally do cause corrosion.The boat is less than a year old thoroughly washed after every trip and even a bit of water repellent spray sprayed on these kind of things and thoroughly cleaned off.
I don't want corrosion to get a hold and was wondering what other people do.Maybe there are some other fittings to do the job.Having a bit of a look around a couple of boat yards all of the tinnys that have side curtains and most other fittings are put on with stainless steel screws etc. Has anyone have any ideas?

[blaze]

Hi Bazz
get a glass boat, I think Tinny owners are stuck with that problem and there is no real cures for dissimialar metal problems, try and isolate the the pieces of dis similar metals, there are some products that attempt to do that, cant recall names though. hope a tinny owner can help you more
gota love glass owner
cheers
blaze

[peterbo3]

Morning Bazz,
A lanolene based spray is the go. Glascraft stock it. Most marine dealers should have one of the several brands available or you could PM Lucky Phill.
They are mixed with a hydrocarbon liquid to enable them to be sprayed & penetrate between fittings. The hydrocarbon evaporates leaving a lanolene coating which will slow down the electrolysis/corrosion to just about zero. These sprays dry hard within 24 hours. Great for battery terminals too.

[Kerry]

Even though they are stainless, there's the issue with alloy but it's way more complicated than simply dissimilar metals but most likely the clips have been pop rivited and as most boat shops keep costs down have probably used an alloy (or stainless but not likely?) with a steel mandrel, different metal #3.

You could check just how they have been fixed (even possibly could be screwed on which could makes things easier) and opt to remove them and refit with GOOD QUALITY ALL alloy pops or SS screws and seat them with a corrosion resistive compound (even something like Lanotec ). Just keep lanotec/lanolin away from canopy zips but

The size of the respective fittings does/can have a lot to do with things but in many cases problems can be reduced to a minimum with some care and proper application.

One thing you could check is that the clips are in fact stainless and some are in fact a type of nickel coated brass?

Cheers, Kerry.

[Lucky_Phill]

One important thing with tinnie additions.

ALWAYS..........ALWAYS........ALWAYS......use a product like Duralec when fitting any other material to the structure of ya boat.

All screws, pop rivets etc should be coated. This WON"T happen in a factory optioned boat, you must do this yourself.

Cheers Phill

[nofrills]

hey bazz
this is what i do to stop the corrosion.ALLWAYS use duralac ,where possible dump the screws and use aluminium rivets with aluminium stems.i also cut nylon washers out of a old detergent drum to stop things like clips from touching the hull.sikaflex is another good product for insulating things.in places where i must use screws,eg trasducer,i just undo them once a year clean them up and wack on more duralac.i wont say i dont get any corrosion but i think im winning the war.
I have heard you can get nuts and bolts made out of nylon or teflon coated or something ,maybe someone else will know about them because they sound like a good thing.
cheers scott

[littlejim]

Bazz,

I've got a F/G boat, but the canopy push studs are all on to aluminium on the windscreen surrounds and canopy supports. When I got the boat they were heavily corroded from galvanic action. After cleaning them up (and replacing a couple of pop rivets that were completely gone) I coated them all (both male and female) with Vasoline. Have not had any problems since. Once or twice a year it pays to check and top up the vasoline because it gradually dries out from the sun's heat, wind, water etc.
Recommend you give this try before doing anything more fancy.

You are stuck with the galvanic dissimilarity because the clips are brass, go onto aluminium, and the pop rivets will be aluminium or stainless steel.
If you have to put new ones on I agree with the recommendations to paint the Duralac joining compound over each bit.

[bazz]

Thanks to everyone for the advice I've received, now I understand more about the problem.This weekend I've got a job to do on a boat.Bazz.

[nofrills]

hey bazz
got a bit more good info for you.Went to fisher boats at bribie today and asked what they do to stop corrosion.they have nylon bolts available there and they also reckon duralac is the ducks nuts.they also told me to use polyethelene to make gaskets for larger fittings.Thats the white stuff used to make cutting boards.Just dont let the missus catch you floggin it from the kitchen 8) 8) .they also said make sure the aluminium rivets have similar stems in them.One of my mates has a fisher boat and ive never seen a spot on it so i figured no use reinventing the wheel.After thinking about it my boat has had a polyethelen board rivited to the flat plate base frame for 7 years ,i pulled it off to have a look and guess what ,not a spec of corrosion under it.SO BRING ON THE CUTTING BOARDS !! 8) 8)
cheers nofrills