[brunolund]

bought a boat in jan. got it running last week. now my hull.

the hull has a buildup of what looks like hard water deposits, but is a PITA to remove. i've tried a wire wheel, a scraper, some hull cleaner from store( i thinbk it's starbrite) but it didn't touch the stuff.

any ideas??? here are some pics.

[ltoolmanb]

I had a 12' aluminum boat that I first cleaned real good with vinegar, then primed with zinc chromate (nasty stuff, wear a resperator) and repainted. From the pic's your alum. hull looks pitted, you might want to mask off the red and primer and paint. Aluminum is tricky though, you have to acid clean it first, (that's why I used the vinegar.) rinse it prime & paint.
good luck!
Lew

[tashasdaddy]

80 grit sand paper on disc grinder, it does look pitted. you may not get it smooth,

[brunolund]

how should i prep it after i grind away the crap? not to familiar with painting alum. which paint and primer to use?

[joeyplumley]

zinc chromate primer is the traditional route. I couldn't find it anywhere - not many places carry it anymore because it's such a health hazard.

I bought a quart of rustoleum's latex aluminum primer for about $8 and brushed it on. It's made to be topcoated with either latex or oil-based after it's dry.

If that was my boat, I'd scrub with vinegar and a soap, rinse, dry, and prime with the rustoleum. Then I'd spray a couple coats of high-build primer, and topcoat with your choice of paint.

[brunolund]

the metal is not pitted, it has acoating on it that feels like sandpaper. this is what i can't get to come off. a fine wire whell on a die grinder didnot work very well, but it does scrape off in places. it looks like it could be sand, but then why won't it come off? tried vinegar and green starbrite, niether worked, no matter how long i left it on. i took some scrapings and put them in a jar one with vinegar and one with starbrite. after two days, the scraping are still there, same as they came off.
would a strong pressure washer work?

[jameskb2]

If it's hard water or mineral deposits, I might try, in a small area as a test, toilet bowl cleaner. Find the "thick" formula, with the highest concentrate of Hydrochloric Acid you can find. I think the Ace Hardware brand is it, around here.

Vinegar is a light acid, but not strong enough to remove hard water stains quickly.

If the toilet bowl cleaner doesn't touch it, then it's something other than mineral deposits more than likely.

[86bonito]

I have the same problem. Boat was left in the water for 2 weeks when it was pulled out I had to scrape all the barnicals off the bottom which left a rough sandpaper like surface. I tried star bright, scoch pad on a drill with commit clenser, oven cleaner, nothing has worked. Tashasdaddy is probably right. I broke down and bought sanding discs at wallmart this morning $3.00 for 5. Good luck! If you try the toilet bowl cleaner please post and let me know if it works before I spend a few hours on my back.

[86bonito]

Just tried the 80 grit on the drill took it right off. However I would feel more comfortable doing it by hand. It may have to wait untill winter the fishing is starting to get hot. I'll pull the motor and the center councle off and figure out a way to get the boat off the trailer and flip her over. 18 1/2 foot starcraft 800-900 lbs. from what I've read. I do not want to do any structural dammage to the sides trying to roll it. Then hand sand and paint.

[brunolund]

i'm using a cupped wire wheel on a drill. it takes it down to the alum. then i'll prime and paint. however i'm going to attempt this on the trailer.

[joeyplumley]

Originally Posted by 86bonito

...and figure out a way to get the boat off the trailer and flip her over. 18 1/2 foot starcraft 800-900 lbs. from what I've read. I do not want to do any structural dammage to the sides trying to roll it...

My 18.5' Starcraft is gutted, and I flip it by myself when painting or working on the bottom. Grab rails etc are removed of course, or they'd get squished.

I would guess the hull by itself weighs only around 200 lbs since I can lift it when sitting flat, upside down on the ground.

[joeyplumley]

Originally Posted by jameskb2

If it's hard water or mineral deposits, I might try, in a small area as a test, toilet bowl cleaner. Find the "thick" formula, with the highest concentrate of Hydrochloric Acid you can find. I think the Ace Hardware brand is it, around here.

Vinegar is a light acid, but not strong enough to remove hard water stains quickly.

If the toilet bowl cleaner doesn't touch it, then it's something other than mineral deposits more than likely.

Muriatic acid (from Home Depot, etc in the pool dept) is hydrochloric acid, most likely in a higher concentration. Just thought I'd mention in case you need to buy a lot of it.

[Coors]

I think it's called csr, from Ace, etc. I get mineral deposits in the house, and that stuff dissolves it.

[jameskb2]

Originally Posted by joeyplumley

Muriatic acid (from Home Depot, etc in the pool dept) is hydrochloric acid, most likely in a higher concentration. Just thought I'd mention in case you need to buy a lot of it.

Sheesh, yeah, I should have thought of that! It's used to clean tile and masonry faces of mortar or grout. Why that didn't come to mind?

I dunno! (I'm getting old?)

[jameskb2]

Originally Posted by Coors

I think it's called csr, from Ace, etc. I get mineral deposits in the house, and that stuff dissolves it.

Never tried CSR. I've heard of it though, from TV ads?

Maybe I will try that in the future for similar work.

[samo_ott]

Up here it's called CLR. Probably the same stuff.

[Coors]

Just went and looked to see what I used last time. Lime Away.
That delicate little screen/aerator on the faucet? Soak for 30 min, all deposits gone.