Hull Preparation & Painting

Corrosion, Paint, Through Hulls, etc.
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shade2u2
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Hull Preparation & Painting

Postby shade2u2 » Tue Feb 21, 2017 12:36 pm

This is my first time & would like some advice... I was hoping this will be a simple process.

I have power-washed my 28 M hull. It looks okay, but I think there is a film of "river much" still in some spots.
My first question - can I use Shoreline hull cleaner on it? I always used it on my fiberglass hull boats. I believe muriatic acid is the active incredient.
Any other suggestions for final cleaning?
I have some Interlux 216 Special Thinner Solvent Quart that I think I'm supposed to prep with. Would this "clean" also?

I'm going to paint my hull with Interlux Trilux 33. This is what is on the boat according to the previous owner. He provided the thinner & paint 2.5 years ago when I got the boat. There is bright blue & dark blue paint layers showing after I washed the crud off. I have black bottom paint to use which I hope will help me know if I have good new coverage. It is rougher than I expected. Should I lightly sand the hull before painting?

Thank you for any advice...
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

Leviathon
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Re: Hull Preparation & Painting

Postby Leviathon » Wed Feb 22, 2017 6:20 pm

I sanded the crud off as it was like a layer of paint. Not a fun job, but paint will not stick well to crud.
Steve and Mary Levi
1973 32' Marinette Fisherman
Twin Chrysler 360's
El Ohssa
St. Joseph, Michigan

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shade2u2
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Re: Hull Preparation & Painting

Postby shade2u2 » Mon Mar 20, 2017 7:52 am

One more question...
My keel has a scrap at the bow. It is about 2" long and it is down to the aluminum but just a surface scrap.
What should I prime or paint this with before covering it with the Interlux 33?
Also, should we use 'zinc chromate' primer paint for this or is this a big NO-NO? I had a note from the previous owner I thought said that this is what should be used, but when seeing 'zinc' in the name I got confused.
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

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bcassedy
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Re: Hull Preparation & Painting

Postby bcassedy » Mon Mar 20, 2017 11:16 am

John,

For the scrape...
I'd get a quart (smallest amount I've seen for purchase) of Interlux's Interprotect 2000E. This is a 2 part epoxy primer. You'll need to get the primer first, then sand down to bright metal. Even if you've previously sanded the scrape down, you'll need to lightly resand it. This is because bare aluminum oxidizes quickly to protect itself and that oxidization prevents good adhesion of paint.

Here's a video link from Jamestown Distributors on how to use Interprotect 2000E. It refers to fiberglass boats, but is applicable to ours as well.
https://www.youtube.com/watch?v=fM-R2_Awgeg
- Once you've lightly sanded the exposed aluminum, immediately...
- Mix the 2 part epoxy sparingly - just enough for what you'll need to paint the affected area. Apply a 1st coat and allow to set up/dry, according to manufacturer's instructions.
- If the scrape is deep enough to warrant your concern, then you want to fill in the affected area. I recommend a 2 part epoxy - PC11 which is waterproof.
-> Mix and apply the epoxy to the newly primed area, smoothing it out as evenly as possible (this stuff sets up like concrete!).
-> Once its cured, you can finish sand it to the level of smoothness you'd like.
-> Apply a second and final layer of Interprotect 2000E.
-> It's now ready for a 2 coat bottom paint application.

Bottom painting (over an existing painted surface)...
Cleaning the bottom of any remaining residue (river muck) should be able to be done with a good quality hull cleaner and a fair amount of elbow grease. I've power cleaned the bottom of my boat, let it dry, scrubbed, rinsed and allowed it to dry. After that I applied new layers of bottom paint (1 white over previous black and then a final black layer - ensures I don't miss a spot). I don't know that you'd need to use a special product to clean it. If it's clean, that's all you're looking for. Just ensure there's no residue from whatever you use to scrub the bottom with. The light sanding of the remaining paint will provide a good adhesion surface for the new paint. If the paint layer behind the crud is solid (ie, it's not flaking off and adhering to the layer(s) behind it), then you can apply your bottom paint to it. Trilux 33's instructions indicate that it can be applied to previously painted surfaces, if that applied to layer is in good condition.

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

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shade2u2
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Re: Hull Preparation & Painting

Postby shade2u2 » Mon Mar 20, 2017 11:40 am

Bill,
Thank you for the details. I'll get the 2000E. Could it be used on trim tabs & rudder also with the interlux33?

The paint on the hull looks solid. the area that I powerwashed already looks pretty clean. I'll see how the rest of it looks when done.
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

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bcassedy
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Re: Hull Preparation & Painting

Postby bcassedy » Tue Mar 21, 2017 10:50 am

Sure, you can use the Interprotect on the trim tabs. That's exactly what I did. I don't see why you couldn't also use it on the rudder, though I leave mine unpainted. The ablative effect of water running across the tabs will wear the bottom paint away a bit faster, but if you pull your boat every year or two, you can clean them up and apply the bottom paint. Interprotect 2000E wears like iron, oops... aluminum alloy. ;-)

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

jralbert
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Re: Hull Preparation & Painting

Postby jralbert » Tue Mar 21, 2017 2:27 pm

I coated everything coatable with the proper primer including tabs and rudder.

Also, the reason to use alternating colors is so you can spot places where the paint has worn thru. I never thought it mattered which color to use on the bottom since you see so little of it from above the water except if your water is crystal clear and you care.

If I had a little paint left over I'd mix it in with the new stuff next season. A little blue in the black paint or vice versa made no diff to me.
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

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shade2u2
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Re: Hull Preparation & Painting

Postby shade2u2 » Tue Mar 21, 2017 3:06 pm

I ordered the Interprotect 2000E today. I'll coat the trim tabs and rudder.
It had light blue, then dark blue & now I'm putting black on but only have the one color.

Thanx all...
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

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BayfieldMarinette
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Re: Hull Preparation & Painting

Postby BayfieldMarinette » Tue Mar 21, 2017 6:33 pm

Any pictures or your project?
1978 Marinette 37' Double Cabin.
440 Chrysler's, 6.5kw Onan.
Bayfield WI.

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shade2u2
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Re: Hull Preparation & Painting

Postby shade2u2 » Wed Mar 22, 2017 10:22 am

I'll get some this week.
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)