Galvanic corrosion in ally boats
gday guys ive got a bit of a problem ive had my ally boat for 3.5 years now and the paint is bubbling near any hardware that has been mounted on the boat
the worst area was near the live bait tank and under the cushions where the steel staples used to hold the side cushions together have rusted the area behind them
the boat gets washed after each use with soapy water and hosed off after that i thought that this was all that was required
since speaking to the boat manufacturer they have advised that i should be using inox around all areas where things are mounted to keep the salt water out......
since looking into this problem ive come to know how much of a problem stainless and aluminuim have with each other and then when saltwater gets involved things escalate but they make products that slow the process duralac and you can sikalfex around the mounted hardware to help stop the saltwater getting in as well
neither of these things were done by the boat manufacturer and when i asked them about it they just said it was poor maintenance
does anyone else think this is just a crap effort by the boat manufacturer i dont wanna name and shame the manufacturer but i think that its a bit shit and was wondering what other people think and if other boat manufacturers take more of an effort when mounting hardware to their boats
bouttime
Posts: 703
Date Joined: 27/07/06
Looks severe for a boat only
Looks severe for a boat only a few years old. You should be using a paste such as duralac around stainless fittings which will help slow it down. I have also been told dont use car wash as it can make things worse. Just use water and a non corosive dish washing liquid. I have a bit on my boat its 8 years old but nothing like that. Just clean it up with some rust kill and respray will look like new.
Madmerv
Posts: 672
Date Joined: 24/01/15
Metals + Water = Corrosion
Can see why you are not to happy there. As you have stated putting a barrier between the dis-simmilar metals will help a lot but like everything in life the builder has to work to a price. If they spend the time / $ putting a rubber gasket between all the metals then the cost of the boat goes up corresponding to the effort. The competitors boats then look like a better option.
You are doing the right thing now by rubbing it back and giving it a respray. then go over the whole boat looking for the danger spots and try to fix them before a problem occures.
If you add up all the time you spend working on the boat and then x by $200 or so then that might be close to the extra cost you would have to pay for the manafacturer to have done it in the beginning.
At the end of the day the problem is there because you are using the boat so i guess you are getting your moneys worth out of it. Wish i could say the same ATM.
Sometimes when the water is quiet, you can hear the fish laughing at you !
Saulty2
Posts: 657
Date Joined: 28/05/10
thats major
think it has not been primed properly before painting, cant blame that on a few screws
resurgence
Posts: 578
Date Joined: 23/04/14
Priming
Galvanic corrosion will usually show as an area where a substantial volume of the metal has disappeared due to corrosion. I don't really see that.
Those large areas of flaked paint look more like the hull wasn't properly etched and primed prior to painting.
grantarctic1
Posts: 2546
Date Joined: 03/03/11
Have to agree
Have to agree with comments above, the whole area looks a poor job was done on the painting. The corrosion has started with the screws/bolts , but shouldn't have spread out that far as in your picture.
Looks like it got under the paint and primmer, then took of like a race horse on meth .
As a suggestion, make sure you have not had an earth leakage around that area. Possibly a pump for the live bait tank. This would explain such a rapid corrosive effect.
ranmar850
Posts: 2702
Date Joined: 12/08/12
What they said
^^^^ This will also inevitably happen if you drill and fasten through an area already painted, you have just given the water a way under the paint and the process will not stop until you sand back and paint. You may also see it happpen where you have scratched clear through the paint and primer.
Tank
Posts: 358
Date Joined: 12/05/12
agree with grantarctic LED lights
Had LED lights under gunnels, wore out and were brittle and cracking, electric current going everywhere but where it was meant to...now no longer on the boat.
Beerbuoy
Posts: 19
Date Joined: 02/07/15
When you put it back together
When you put it back together use Duralac or Mastinox on the fasteners and between different metals. This will help prevent disimilar metals causing corrosion.
Just make sure to wear gloves when using this stuff as its quite toxic, especially Mastinox.
careybrad
Posts: 3
Date Joined: 18/06/13
primed up
yer so ive sanded it all back and got some holes welded up and i have now got it all primed up using a 2pac epoxy primer
and yer basicly i have brought a tube of the duralac (the new eqivilent that a different boat builder reccomended) and spoken to someone about the paint its a tabs boat built in qld and im not sure if there painting process is as good as some of the more expensve boats but i like the boat and i should have fully nipped it in the butt im going to take everything mounted on the boat and re mount with duralac and sikaflex its gonna be hard to blend the paint in but i got the paint colour matched and now im just waiting for a nice dry weekend so i can finish it and get the boat back in the water ill post some progress pics
fish200red
Posts: 55
Date Joined: 06/02/11
tabs
i have a tabs as well,mine has corrosion behind every stainless press stud,The press studs also had aplastic washer behind them to stop corrosion but the stainless screw is what did most of the damage i think.
My boat does have the same behind the cushioning but not the back deck like yours
yes i agree that they are a good solid boat and handle conditions great,mine is a 650 with verado 225hp
cheers rob
careybrad
Posts: 3
Date Joined: 18/06/13
yer ive removed all the press
yer ive removed all the press studs the paint came up good mostly a few runs when we painted but ive sanded them back and im gonna re prime 2 sections and paint again
but yer i removed the cushions completly and everything is getting remounted with sika and duralac