electrolysis on Aluminium boat

[rexy]

i have a quintrex 4.55 escape 2001 I have noticed bubbles under the white paint with a white powdery muck underneath the paint is there a way of fixing the areas and a way to prevent it from happening again.

[Cowfish13]

Good question! We've got the same problem in some parts of our boat.

Anybody know of a way to stop it? Or if it is a major threat?

[bootyinblue]

I have also got it around 80% of the afteramrket fitted equipment fitted on my boat.

[Davo_Dinkum]

its a common thing since most ally boats are painted without a primer. they just etch them then paint.its a money and time saveing thing boat builders do ,there out to make money not give a paint job that last 30 years.

sand them back with some 80 then finish off with 180 then etch the rub over with 240 or a light pad and paint .

i just spend today rubbing and preping a 19 foot profish. its my dads boat bro and me cleaning it up and repainting it for his b day.bro is a panel beater/panter,and i was a ta in that trade 15 years ago.

[Davo_Dinkum]

i'll ask my bro about it and let u guys know ok

[Feral]

Easiest way to stop it is put an active kit on the boat. Keeps a charge running through the boat stopping corrosion. Costs though!

[Davo_Dinkum]

i got one of them on my 4x4 dosen't do sh*t but thats on an old car .

i think they would quite well on a new car or boat or a old boat thats has been cleaned up right .

[Davo_Dinkum]

* would work quite well

[noname]

they're not humidity blisters starting??

[rexy]

sorry but what is a active kit ??:cheer:

[rexy]

most of the bubbles are around any stanless screws or around the top trim that connects the top of the boat to the hull.there are heaps there on that trim

[Feral]

Article on electronic corrosion protection

http://www.prlog.org/10102288-aussie-company-revolutionizes-corrosion-prevention-damage-to-boats.html

[noname]

ah, it's because stainless doesn't get along with aluminium, duralak i think is the name of the gear to use, pull the screws out dab some of the duralak on the thread and re apply, a pain i know.

[billythakid]

electrolysis in a simple term is two different metals reacting with one another , the weaker/softer metal will always corrode away first , rubber or silastic between any aftermarket fitting will slow it by not having the two metals touching .

also dissconect the positive terminal or install a battery switch to stop any residual current from the battery thru the motor mounts .

positive charge kits like in 4wd's ( similar to the sacrifical anode on the leg of most outboards ) work to a extent but take one off the car and watch how quick rust appears after having one on there for a while

i think from memory brass is the only metal that doesnt react with alloy . ( i think )

[Davo_Dinkum]

about u can do it clean it up repaint it then put the stuff noname said or silastic between all the nuts and bolts ,screws ,fittings etc that will slow it down.

u got 2 different metals reacting with one another plus salt water in the mix .there is going to be electrolysis and corrosion.

notice there is always less on non painted ally boats .no where for the salt water to be trapped.

[mick fillet]

if the boat is in storage like on a trailer earth the hull out to the ground use the anchor chain this takes the current caused from electrolisise away .put a decent multi metre on the hull then do it watch the current drop

[STU]

It happenedd to my first boat a quintrex explorer trophy I got it welded up a couple times lots of holes started to shit me I was told the best thing is to sell it so i did.

[Feral]

Probably a lot more of it around, since its nearly 3 years since fisho's were allowed to hose the salt water off their boats after a trip. Salt makes the electrolysis much worse.