Paint blistering/corrosion-aluminum boat

[motownbob]

I have a 1997 crestliner sportfish. Stictly a fresh water boat, kept on a trailer. Lately i have noticed some very tiny blister like bumps on some of the painted surfaces of the aluminum, especially noticeable around the drains in the transom[splashwell]. Does anyone have any idea on what is causing this? What to do to stop this from getting worse? Thanks, Bob

 

[Solittle]

Re: Paint blistering/corrosion-aluminum boat

I'm going to guess that you have an electric start motor with battery. If so you may have a small current leak somewhere. No big deal - just disconnect the battery when not using.

 

[allanwh]

Re: Paint blistering/corrosion-aluminum boat

I have a 20 foot aluminium hull with a 130 hp honda and I am having the same experience.. Paint Blistering around rod holders and where stainless screws penetrate the hull. I will disconnect the batteries as suggested but I have also been told that a sacrificial anode on the hull will help. Can anyone add to this..<br /><br />Thankyou

 

[akriverrat]

Re: Paint blistering/corrosion-aluminum boat

yeh. get rid of the paint. it traps water beneath it and rots the aluminum. paint may be pretty but with most aluminum boats it ends up being a liability.

 

[Luna Sea]

Re: Paint blistering/corrosion-aluminum boat

Disconnecting the battery wont help if the battery's not in a box. I learned that one calm drizzly weekend sitting in salt water. Yup, right where the deck meets the back of the boat I got those dreaded pin holes. Current travels through the moisture or something to that effect. Drilled a couple of holes in the hull and added a bolt on zinc. If you do this, lock the studs/bolts in place with nuts and washers, then add the zinc otherwise when the zinc goes you'll start leaking.

 

[1sinbad2]

Re: Paint blistering/corrosion-aluminum boat

I am considering a 2000 crestliner Sportfish 1750 and the paint on the aluminum plate around the perimeter of the bow is blistering. Should I just remove the paint and polish the aluminum or install some sort of sacrifical anode. I'm a newby--but is a "zinc" a sacrifical anode? I am not a corrosion engineer. How or where should the sacrifical anode be placed.

 

[Bondo]

Re: Paint blistering/corrosion-aluminum boat

I just went thru this a couple of years ago, with my 74 Starcraft 221 Islander.......<br />Before I painted my hull, I noticed that anywhere there Wasn't any paint left, I had tons of Pin-Holes...... The Original paint was getting pretty thin over most of the hull....<br />Anyway, I sanded, zinc primed, sandable primed, sanded,+ sanded,+ Shot it with a 2-part Urethane paint..... <br />I then added 3 coats of brushed/rolled Rustoleum, Below the water line........ Being a trailer boat, I now just touch up the bottom a couple times a year, with just a disposable brush....<br />After all this work I found some more pits in some scratches......<br />I found that by Bonding the boat, the Hull should be bonded to the engine, just like the outdrives are bonded to the engine...... This gets everything on a level playing field, so to speak.....<br />Then, You have to Ground All of your Electrical Circuits Directly to the Batteries.......<br />And the Pitting Stopped.....<br /><br />AAnnndddd, The Added Bonus of a Properly Bonded Aluminum Hull(Cabin prefered)........<br />Is the Safety Factor of the Faraday Cage Effect,<br />In case of Lightning Strikes...........

 

[Lark40]

Re: Paint blistering/corrosion-aluminum boat

I'm reading these posts in amazement.<br /><br />My Crestliner outboard runabout is 45 YEARS OLD! Electric start since new and has no corrosion or leaks whatsoever.<br /><br />And, it runs in semi-salt water (Chesapeake Bay).<br /><br />Add all the zincs that people are recommending, you have some sort of electrolysis problem.<br /><br />Bondo - we also have the same (other) boat. I have no corrosion, but the rivet problem is well known. I'm printing out all your good advice.

 

[1sinbad2]

Re: Paint blistering/corrosion-aluminum boat

Bondo--how do you bond the boat to the hull? Can the paint be removed and the aluminium be left unpainted?

 

[Bondo]

Re: Paint blistering/corrosion-aluminum boat

how do you bond the boat to the hull?

???? Boat to Hull,??? 1 in the same isn't it????<br />Go do a Google Search.... It's Really a Very Indepth thing..... <br /> BASICLY , Grounding(bonding) Everything Together.....<br />

Can the paint be removed and the aluminium be left unpainted?

I have No Idea....<br />I prefer Painted Boats.... <br />Bare Aluminum will Oxidize in a matter of Hours,+ turn Grey......