Bottom paint dilema

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shade2u2
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Bottom paint dilema

Postby shade2u2 » Mon Apr 16, 2018 12:31 pm

I am in the process of purchasing a 39.
The hull (waterline down) was 'soda-blasted' down to the bare aluminum about 2 years ago. It was painted with a barrier coat and Seahawk ablative paint. With this extremely important item being done, I was very interested in the boat. There are many other updated systems, electronics and accessories as well.
The survey was done this past weekend and almost everything checked out well.
The main thing that did NOT look good to the surveyor is that the paint appears not to be adhering well to the aluminum hull. There are many little specs or spots where the aluminum is showing or the paint can be easily rubbed/scraped off. There is not any evidence of pitting or "metal wasting" as he called it. Apparently primer was not used and I don't know yet what barrier coat was used.
I originally saw some evidence of this on the side below the water line but didn't see it throughout the hull with the light that I had.

Can this be "touched up" where the paint has come off or will easily come off with any expected success?

My gut feeling is that it should be re-done now with the proper method and materials.

What advice do the experts here have?
Last edited by shade2u2 on Mon Apr 16, 2018 7:12 pm, edited 1 time in total.
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

jralbert
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Re: Bottom paint dilema

Postby jralbert » Mon Apr 16, 2018 1:17 pm

This MAY be evidence of failure to do the job properly. As you may have read, aluminum must be primed/barrier-coated within a few hours of blasting or sanding down to clear metal or it skins over, unable to hold paint. There are clear procedures for applying coatings to bare surfaces and they may not have been followed here as your instincts are telling you. The good news is that the surface isn't pitted.
-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: Bottom paint dilema

Postby shade2u2 » Mon Apr 16, 2018 2:13 pm

I am sure that the paint or preparation was did not work right. The seller paid someone to soda blast it and then painted it himself.
Now I need to handle fixing this. The seller has been great and is planning to paint the bottom as part of the purchase agreement (along with other items). My concern is that touching up where aluminum is showing now and then doing the entire bottom with Seahawk ablative paint is a bandaid and this issue will resurface for me in a year or two.
I expected to have a 10-20 year bottom paint job, not 1-3 years. I'm hope that we will work our something. As I said, the seller has been great to work with so far.
Any advice on how to negotiate this?
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: Bottom paint dilema

Postby bcassedy » Mon Apr 16, 2018 3:49 pm

John,
I've never heard of a bottom paint job lasting as long as you're hoping. I've painted my own boat a couple of times since we bought her in Jun 2010. By design, the ablative paints are intended to wear off in order to rid the bottom of slime, crustaceans, and other undesirable stuff. There are "harder" bottom paints but even these will wear off over time, and sooner than 10 years.

It sounds as if the PO, as you indicated, had the bottom soda blasted and then painted it him/her self but didn't adhere to the proper procedure to do that paint job. I believe that to touch up and/or paint the entire bottom without correcting the previous paint job's flaws will just result in your having to repaint next season.

This is a link to a post I made some time back on painting the bottom: viewtopic.php?f=4&t=1222&p=8817#p8817

As I mentioned, I've painted the bottom twice since 2010. However, I only needed to sand blast (or in your case, doing a soda blast) once. The 2 part epoxy primer (Micron's Interprotect 2000e) was applied in 2 coats before applying 4 coats of bottom paint. There was some pitting which I filled in AFTER the 1st primer coat was applied (within an hour of the bottom being sand blasted). Then applied the 2nd primer coat. Those primer coats held up well so I only needed to lightly sand (after a good water blasting) to rough up the well adhering previous bottom coat before applying the 1st coat of new bottom paint.

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: Bottom paint dilema

Postby shade2u2 » Mon Apr 16, 2018 6:43 pm

Bill,
I understand ablative bottom paint. I apologize if I didn't make that clear.
The barrier coat (as I call it) that is coming off is what would normally be the 2 part epoxy Interprotect 2000E (which I used on my 28). The issue is not the ablative Seahawk that the seller used. I'm aware that ablative paint is re applied every couple of years. The "base paint" that is directly on the aluminum is coming off in specs or spots and exposing the bare aluminum. That layer seems very thin to me. From what I understand this layer should last for many years and one should only need to apply ablative bottom paint every couple of years. If not, no one would own a Marinette... lol
I wonder if the preparation may not have been the best. I think that I know the answer to this, but...
"Can this be "touched up" where the paint has come off or will easily come off with any expected success?" Could sanding or scraping anything loos and then applying 2000E on the aluminum spots work?
I checked out your post. I appreciate that and there is a lot of good info there.
One question, when we say that the bare aluminum needs painted in a few hours, does that mean 1-2, 3-5 or 6-10 hours?
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

jralbert
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Re: Bottom paint dilema

Postby jralbert » Mon Apr 16, 2018 9:33 pm

You asked for a suggestion on negotiation - here 'tis. Since the seller didn't paint it correctly I wouldn't give him the job of trying to get it right now. Instead, acknowledging that it wasn't done properly, he could knock some dollars off the price, dollars you'd use to have the job done yourself after the sale. I won't suggest an amount but be prepared for it to be less than the actual cost of a blasting. Perhaps an even or nearly even split based on a professional estimate you get from a soda/sand blast vendor. Having a good bottom paint job will save you money at the fuel dock so controlling it yourself will be important. You will certainly not be able to patch this.
-0-
Also, when I repainted, I recall the time interval as immediately to no more than 4-6 hours. The crew completed work on my boat around 3pm and the barrier coat was sprayed on, completed around 5pm. Once done, we could relax about getting subsequent coats on. The guys in the tech department of the paint mfr will be happy to review it all with you
-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: Bottom paint dilema

Postby shade2u2 » Tue Apr 17, 2018 2:09 pm

Thank you for the perspective...
One other question, is "soda blasting" a common or good type of blasting to use on Marinettes? Could there be issues with this media?
John
John
1984 28 Express Hardtop FOR SALE
w/single 360 1.5:1 reduction drive
Ohio and Muskingum Rivers (Marietta, OH)

jralbert
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Posts: 491
Joined: Fri Jul 11, 2014 9:15 pm

Re: Bottom paint dilema

Postby jralbert » Tue Apr 17, 2018 3:21 pm

Good question: mine was done using glass beads as the abrasive. But "soda" (prob a ground up mineral) and sand are also common. Check w/blasting contractor and/or the paint mfr. I don't have the tech expertise to recommend one over the other.
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

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bcassedy
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Re: Bottom paint dilema

Postby bcassedy » Tue Apr 17, 2018 8:24 pm

John,

You could spot sand areas where the paint's flaking, apply a couple of coats of Interprotect 2000e and a couple of coats of bottom paint. But importantly, those areas that haven't flaked off could do so shortly after you put her in the water.

I would definitely try to work something out monetarily-wise with the PO. You want to put yourself in control of what happens to the boat after you've bought it. Whether you do the work yourself (maybe short of the blasting part <as I did> and just be standing by to start the actual painting), or have it done professionally. Either way you are callin' the shots. Me... I like saving money (student of one, FastJeff, here on the site. :D ). And when you're finished painting her, you can stand back, brewski in hand, and be able to say "I did this myself, and damn, doesn't she look good!

I can tell you firsthand that sand blasting is totally thorough in paint removal. It also is the hardest on the hull as the abrasive can remove hull material (aluminum) if not done properly. I have no experience with glass bead or soda blasting but I have read they do remove the paint effectively and are easier on the hull.

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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