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11-02-2022, 09:45
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#1
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Registered User
Join Date: Aug 2018
Location: Nomad
Boat: Hunter 410
Posts: 323
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Selecting Bottom Paint
Hello friends,
I'm prepping for my first haul-out since surveying this boat. It's been about 2 years since the bottom has been painted, and almost as long since I've owned it, so I'm planning to put a couple of coats on while the boat is hauled. The boat stays in the water year-round, always salt or brackish, and I travel quite a bit so there's no specific water temperature or salinity or anything like that.
I have several questions about figuring out what paint to choose, and although Google yields dozens of guides, reviews, etc. they all seem to assume a baseline understanding that I just don't have...
1. Do I need to remove what's on there now? I know that the current paint is ablative, but I don't know what kind of paint it actually is. From what I've read, you can put additional coats of ablative paint on over top of old ablative BUT, I've also read that there's a difference between "sloughing" and "ablative." And I had a chart that indicated I couldn't put "ablative" over top of "sloughing." How do I know if my current paint is sloughing or not? From what I can tell it's just different degrees of softness in the paint, and since I have no frame of reference, I have no idea if my paint is "really soft" or just "soft."
2. Do I care whether it is water-based or solvent-based? I'm letting the yard do the actual painting and sanding (They don't allow DIY sanding for safety/eco reasons, and I'm okay with the price). I've read water based may be easier to apply, but if I'm letting the pros do it, do I need to care?
3. What is the difference between the $80/gal paints and the $400/gal paints???? What differentiates a paint that will last several seasons vs. one I'll have to repaint next year? Is it just the % copper, or is there more to it?
I want a paint that will work and last several years. I imagine that means I'll need something on the expensive end of the spectrum, but I really don't understand what criteria to compare them on.
__________________
Time and tide wait for none
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11-02-2022, 11:20
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#2
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Registered User
Join Date: Sep 2014
Location: Fiji Airways/ Lake Ontario
Boat: Legend 37.5, 1968 Alcort Sunfish, Avon 310
Posts: 2,749
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Re: Selecting Bottom Paint
DuckDuckGo is your friend. Here's a nice summary: https://www.goodoldboat.com/pdfs/GOB...ntifoulant.pdf
You didn't ask, but be forewarned that there are different paints for fresh water vs. salt water (it would be easy to select the wrong one.)
I'd ask the yard what type of paint they plan to use, and why. They probably have great insights specific to those conditions.
I'd be surprised if you find $80/gallon paint. I pay up to $80/quart.
__________________
There are too many gaviiformes here!
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11-02-2022, 11:43
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#3
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Registered User
Join Date: Oct 2007
Location: Lakewood Ranch, FLORIDA
Boat: Alden 50, Sarasota, Florida
Posts: 3,467
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Re: Selecting Bottom Paint
Quote:
Originally Posted by JebLostInSpace
1. " How do I know if my current paint is sloughing or not?
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You don’t but it’s irrelevant.
Quote:
2. Do I care whether it is water-based or solvent-based?
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The carrier base evaporates making it irrelevant.
Quote:
3. What is the difference between the $80/gal paints and the $400/gal paints????
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Copper content is the most important criteria.
Some have additional algaecides and additives to minimize slime, however, as you apparently aren’t confining travel to one limited area, it makes no sense to buy specialized paint
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12-02-2022, 08:19
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#4
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Hull Diver
Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 5,428
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Re: Selecting Bottom Paint
Quote:
Originally Posted by JebLostInSpace
1. Do I need to remove what's on there now? I know that the current paint is ablative, but I don't know what kind of paint it actually is. From what I've read, you can put additional coats of ablative paint on over top of old ablative BUT, I've also read that there's a difference between "sloughing" and "ablative." And I had a chart that indicated I couldn't put "ablative" over top of "sloughing." How do I know if my current paint is sloughing or not?
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Sloughing paints are different from ablatives in that they have an uncontrolled release of biocide. Further, they are extremely soft and when cleaned release an impressive plume of color, much more than an ablative paint will. If the paint is red in color, cleaning it will make it appear as if a cow had been slaughtered in your slip. Fortunately, these paints are uncommon. And no, you should not apply an ablative over a sloughing paint.
Quote:
Originally Posted by JebLostInSpace
2. Do I care whether it is water-based or solvent-based? I'm letting the yard do the actual painting and sanding. I've read water based may be easier to apply, but if I'm letting the pros do it, do I need to care?
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Water-based paints are more environmentally friendly. If that is not an issue for you, my personal recommendation is to avoid them as they also tend to be less effective than traditional solvent-based paints.
Quote:
Originally Posted by JebLostInSpace
3. What is the difference between the $80/gal paints and the $400/gal paints????
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As with most things, you get what you pay for. Cheap is not good and good is not cheap. Bottom of the line paints will provide anti fouling protection for a shorter time than better paints and do a poorer job of it while it is working.
Quote:
Originally Posted by JebLostInSpace
What differentiates a paint that will last several seasons vs. one I'll have to repaint next year? Is it just the % copper, or is there more to it?
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I can't tell you the technical differences between multi-season and single season paints. But if you do your boating in an area where weather permits keeping the boat in the water year-round, why would you want a single-season paint?
Quote:
Originally Posted by JebLostInSpace
I want a paint that will work and last several years.
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Using this as a criteria, you should know that a properly applied hard paint (and by this I mean two coats of paint) will last longer than an ablative. That's just the nature of the beast. On the other hand, ablatives can be exposed to air for extended periods whereas hard paints cannot. Something to consider if hauling the boat for any reason is a likelihood. Further, ablatives tend not to build up layer upon layer after successive bottom jobs like hard paints do. With hard paints, this means the eventual removal of all the paint on the hull.
I personally only ever recommend any flavor of Pettit Trinidad (hard) or Interlux Micron 66 (ablative.) All others run a distant second at best, IMHO. But YMMV.
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12-02-2022, 08:25
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#5
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Registered User
Join Date: Oct 2007
Location: Lakewood Ranch, FLORIDA
Boat: Alden 50, Sarasota, Florida
Posts: 3,467
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Re: Selecting Bottom Paint
I would also note there is no standard distinction between so-called sloughing paints and ablatives. It's largely a marketing terminology
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12-02-2022, 08:26
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#6
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Hull Diver
Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 5,428
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Re: Selecting Bottom Paint
Quote:
Originally Posted by S/V Illusion
I would also note there is no standard distinction between so-called sloughing paints and ablatives. It's largely a marketing terminology
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That is 100% untrue and had you ever cleaned a sloughing paint you would know that.
Ablative Paints
Ablative types of antifouling are more efficient at delivering biocide
than Hard antifoulings and use less biocide to provide more antifouling
protection. To ablate means to ‘wear away’ or ‘erode’, and there are
many antifouling paints that work by wearing away, but there are
several different ways that the paints wear away.
Soft Rosin-Based Sloughing Antifouling Paints
These paints are made with natural rosins and are the softest type
leaching paints. They were originally developed so that a boat could be
painted between tides so they dry quickly. The older formulas required
they be launched within 72 hours of painting. These paints erode quickly
and are least expensive antifouling paints offered. This type of paint is
used on boats with displacement hulls and commercial workboats.
https://www.fawcettboat.com/images/I...ouling-101.pdf
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16-03-2022, 08:48
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#7
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Registered User
Join Date: Dec 2019
Location: Florida
Boat: Leopard 50
Posts: 12
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Re: Selecting Bottom Paint
Quote:
Originally Posted by fstbttms
Sloughing paints are different from ablatives in that they have an uncontrolled release of biocide. Further, they are extremely soft and when cleaned release an impressive plume of color, much more than an ablative paint will. If the paint is red in color, cleaning it will make it appear as if a cow had been slaughtered in your slip. Fortunately, these paints are uncommon. And no, you should not apply an ablative over a sloughing paint.
Water-based paints are more environmentally friendly. If that is not an issue for you, my personal recommendation is to avoid them as they also tend to be less effective than traditional solvent-based paints.
As with most things, you get what you pay for. Cheap is not good and good is not cheap. Bottom of the line paints will provide anti fouling protection for a shorter time than better paints and do a poorer job of it while it is working.
I can't tell you the technical differences between multi-season and single season paints. But if you do your boating in an area where weather permits keeping the boat in the water year-round, why would you want a single-season paint?
Using this as a criteria, you should know that a properly applied hard paint (and by this I mean two coats of paint) will last longer than an ablative. That's just the nature of the beast. On the other hand, ablatives can be exposed to air for extended periods whereas hard paints cannot. Something to consider if hauling the boat for any reason is a likelihood. Further, ablatives tend not to build up layer upon layer after successive bottom jobs like hard paints do. With hard paints, this means the eventual removal of all the paint on the hull.
I personally only ever recommend any flavor of Pettit Trinidad (hard) or Interlux Micron 66 (ablative.) All others run a distant second at best, IMHO. But YMMV.
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Good questions and Good Answers...Thx
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