Help with bottom paint prep

Studini
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Help with bottom paint prep

Postby Studini » Mon Jan 14, 2019 6:37 pm

So bought the boat in October. It's currently dry docked outdoors at my old marina, moving in the spring. I would like to put fresh bottom paint on as it has some wear/bare spots and I don't know the last time it was done. Question is what is the best way to prep with limited access to power/sand blaster? Can I prep it periodically through out winter on those days we get above freezing? Thinking a wire brush on cordless drill?? Any help is greatly appreciated.
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88 32’ Fisherman
“Get Busy Livin”
Twin 360’s
Fairport Harbor, Ohio

javalin390
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Re: Help with bottom paint prep

Postby javalin390 » Fri Jan 18, 2019 4:28 pm

I was always told never use a wire brush on a Marinette, only 3M abrasives, like the little "Roll-Lock" discs that you can put on a drill. Antone ever heard the same?
Jim Elias
1974 37' SedanFlybridge
Twin 360 Chryslers.
Marblehead, Ohio

jralbert
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Re: Help with bottom paint prep

Postby jralbert » Fri Jan 18, 2019 9:18 pm

Heard brass brush is OK. If you recall that aluminum skins over quickly - within a few hours - and the coating it forms will not allow paint to stick, make sure that if you do abrade to bare aluminum you allow the first (etch coat) quickly. You'd have to check mfr advice on application temperature. If the day you pick to get down to bare metal is too cold to apply the first protective coat you'll have to go back over it later (but it won't be as hard). Once the initial coat is applied you can put the other barrier coats on at a later time. Sand or bead blasting is effective. You say you have limited access - does that mean no access?
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

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Busia
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Re: Help with bottom paint prep

Postby Busia » Sat Jan 19, 2019 1:16 am

Wait until it is warm enough to paint, paint early in the day so it dries before night time. If you are just spot painting find out what the paint manufacturer recommends to do. You always want to use a stainless steel brush or sandpaper for cleaning. If you only clean off the bottom paint and there is primer left, you can just put on more bottom paint. If you get down to bare aluminum you have to put on a prime coat of paint for the other paint to stick to. I've used Phosphoric acid in the primer, works very well. It will be called metal etching primer. Otherwise all brands of paint will tell you to have clean dry bare aluminum and to prime it immediately. Sandblasting, bead blasting or sanding will prepare the metal. For small areas I sand with a pole sander that you can get for doing drywall. Then paint with a roller on an extension. ( a push broom handle or the pole sander handle is threaded to fit the handle of the roller frame ) If you have much painting to do, a roller is the way to go. First thing is decide what brand of paint you are going to use. Do not even think about any of them that have copper in them.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

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Busia
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Re: Help with bottom paint prep

Postby Busia » Sat Jan 19, 2019 1:30 am

Do you need new anodes? If so order them from Boatzincs.com They have the best prices and they will know exactly what you need. Then if you are going to change anodes you can slop paint on the old ones and it won't matter. Then just sand, paint and then change the anodes. Go to a welding supply and ask for a stainless toothbrush. Use that to clean under the anodes and small areas that need paint. Works good for cleaning the props too. Do you need new cutless bearings? ( the fiber bushings for the rudders and prop shafts. If you do, get them ordered. I think you will use the size called "Betty".
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

Studini
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Joined: Wed Oct 24, 2018 8:00 pm

Re: Help with bottom paint prep

Postby Studini » Sun Jan 20, 2019 8:05 pm

Thanks for the pointers. Think I'll end up using stainless wire brushes on a cordless drill.
Would like to sandblast but not sure how big of a mess that would make and I'd need a gas powered air compressor. Might be doable as long as I could contain the mess as it's on in Jack stand at the marina so need to keep things clean.

Is it ok to recoat over any existing bottom paint that is in good shape?
88 32’ Fisherman
“Get Busy Livin”
Twin 360’s
Fairport Harbor, Ohio

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Busia
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Re: Help with bottom paint prep

Postby Busia » Sun Jan 20, 2019 10:05 pm

Sure, you can paint over old paint. Just a waste of time to put new paint on old paint that is flaking or peeling. Same for painting directly on aluminum. It has to be done right or it will not stick.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

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bcassedy
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Re: Help with bottom paint prep

Postby bcassedy » Mon Jan 21, 2019 8:20 am

I've repainted the boat's bottom after a good sanding and wipe down. The last repaint was in July, 2017 (boat didn't make it into the water that season :( ) . The boat's always pulled at season's end and then power washed before going up on blocks. Did that this season and a LOT of the previously applied bottom paint (Micron CF) came off! I've had similar situations (but not to the extent I saw this past October) occur in previous years at season's end. I'm wondering....
1. Was the delay in the boat going back in the water (painted but left out in elements when it normally would've been submersed) a contributing factor?
2. Poor preparation/application. ( I don't want to think I missed something, but have to add it as a consideration. )
3. Micron's paint just doesn't stand up to pressure washing (paint was coming off in very small flakes over large areas, the transom appears to possibly need sanding, priming, and bottom paint over most of it).
-- I am SERIOUSLY considering a different brand of paint for the bottom. Will be reading as many posts here on what others have used and success.
-- would love to hear other's stories on..
A. what they used
B. did you pull your boat at season's end
C. did you pressure wash boat bottom and results.

Bill
Bill & Sharon Cassedy
"Sunset Seeker"
'88 32' Sedan Bridge
Located in Aurora, In.
Twin 318cu in Chrysler
1.5:1 Velvet drive trannies
Fresh water only