Bottom paint question

7raptor

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trying to figure out which bottom paint to get

New 24' Robalo CC with a 300 Yamaha, boat will do 40+ in a flat sea.

Plan to keep in a slip and maybe remove for a month or two in March/April

Ablative? Hybrid?
 
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apogee

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Your call.. The hybrids come in some pretty nice colors. If you are going to float your boat are you going to barrier coat the bottom before you apply bottom paint?
 
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7raptor

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Your call.. The hybrids come in some pretty nice colors. If you are going to float your boat are you going to barrier coat the bottom before you apply bottom paint?

Not sure what that means - the whole hull comes gel coated from the factory...id like to leave it in a slip 75% of the time but be able to pull it out sometimes when I'm traveling etc
 
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tanner.s

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Not sure what that means - the whole hull comes gel coated from the factory...id like to leave it in a slip 75% of the time but be able to pull it out sometimes when I'm traveling etc
A lot of people opt to put a coat of epoxy barrier coat down before the bottom paint itself.
 
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apogee

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Gotcha - to further protect the gel coated hull?
Gelcoat is a Polyester, sometimes a Polyvinyl but most likely a Polyester in your case. It looks solid, but it is not. It has a high degree of porosity and absorbs water. Many times when you float for extended times micro organisms enter the gelcoat through the porosity and colonize between the gelcoat and the structural substrate. As they metabolize they create a gas that slowly but surely separates the gelcoat from the substrate in the form of "Blisters", this is not good. Epoxy is a omni directional molecule that has no porosity, but is photosensitive. One of the great working features of epoxy is using it as a barrier coat below the water line. You put on your barrier coat and then your bottom paint to prevent blistering. Not needed if your boat spends most of it's life on a trailer. If you weigh a new boat (polyester) then weigh it again in five years after floating it for 75% of the time you will see a significant increase in weight. Don't you just love tech!
 
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7raptor

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Gelcoat is a Polyester, sometimes a Polyvinyl but most likely a Polyester in your case. It looks solid, but it is not. It has a high degree of porosity and absorbs water. Many times when you float for extended times micro organisms enter the gelcoat through the porosity and colonize between the gelcoat and the structural substrate. As they metabolize they create a gas that slowly but surely separates the gelcoat from the substrate in the form of "Blisters", this is not good. Epoxy is a omni directional molecule that has no porosity, but is photosensitive. One of the great working features of epoxy is using it as a barrier coat below the water line. You put on your barrier coat and then your bottom paint to prevent blistering. Not needed if your boat spends most of it's life on a trailer. If you weigh a new boat (polyester) then weigh it again in five years after floating it for 75% of the time you will see a significant increase in weight. Don't you just love tech!

THANK YOU

They're doing two coats epoxy. How do I choose between hard and ablative?
 
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7raptor

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Your call.. The hybrids come in some pretty nice colors. If you are going to float your boat are you going to barrier coat the bottom before you apply bottom paint?

Yes. Will epoxy two layers first. How do I pick between hard and ablative?
 
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apogee

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Yes. Will epoxy two layers first. How do I pick between hard and ablative?
Ablative is just what it sounds like. It constantly sheds. So if you put Ablative epoxy barrier coat (Awlgrip) on the hard bottom, it will slowly slough off, this keeps your bottom smooth but wears away after a year or so, it dissapears because of the water moving past your hull kind of washes it away like dissolving hard candy. Some think not good for fast boats (makes it dissolve faster) or boats that just sit around (because lack of water movement prevents sloughing). If the boat is out of the water it reacts to the atmosphere and exfoliates fast as the cuperous oxide combines with the air and the anti fouling properties are gone. Ablative is the pick over hard if in the water on a slow boat (sailboat) that is used and does not set for long periods of time.
Hard epoxy is for when your boat is on the trailer. It has less tendency to combine with the air and maintains it's anti fouling properties longer, when floating the water penetrates deeper and deeper into the paint over time and uses up the anti fouling agent. Some use Tributyltin Flouride and it is bad ass. Hard bottom paint does not go away. The anti fouling agents go away but the paint stays and gets thicker with each application. This being said...Fast boat, hard bottom paint.
Do not apply hard over ablative...It will just slough off....you could apply hard, with ablative over the top which works out pretty well when the ablative wears away there is still hard anti fouling paint underneath until you can haul out, bead blast and do it again..........Hope this helps..............Ap
 
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7raptor

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I'd say this is a fast boat...sounds like hard is great but goes to shit whenever it goes out of the water for more than five minutes?

Ablative is just what it sounds like. It constantly sheds. So if you put Ablative epoxy barrier coat (Awlgrip) on the hard bottom, it will slowly slough off, this keeps your bottom smooth but wears away after a year or so, it dissapears because of the water moving past your hull kind of washes it away like dissolving hard candy. Some think not good for fast boats (makes it dissolve faster) or boats that just sit around (because lack of water movement prevents sloughing). If the boat is out of the water it reacts to the atmosphere and exfoliates fast as the cuperous oxide combines with the air and the anti fouling properties are gone. Ablative is the pick over hard if in the water on a slow boat (sailboat) that is used and does not set for long periods of time.
Hard epoxy is for when your boat is on the trailer. It has less tendency to combine with the air and maintains it's anti fouling properties longer, when floating the water penetrates deeper and deeper into the paint over time and uses up the anti fouling agent. Some use Tributyltin Flouride and it is bad ass. Hard bottom paint does not go away. The anti fouling agents go away but the paint stays and gets thicker with each application. This being said...Fast boat, hard bottom paint.
Do not apply hard over ablative...It will just slough off....you could apply hard, with ablative over the top which works out pretty well when the ablative wears away there is still hard anti fouling paint underneath until you can haul out, bead blast and do it again..........Hope this helps..............Ap
 
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apogee

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Ablative goes to shit when out of the water . Hard is fast boat / boat on trailer...............m
 
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In 2013 I barrier coated before bottom painting on a previously unpainted '87 BWhaler. Prep was most of cost. Used 2 coats Interlux2000e, followed by Interlux Ultrakote. Boat stays in slip year round, except for outboard service evry 100-300 hrs. Usually a day or two.
Got 3 years out of that paint- it's last 3 months it needed a slime wipe about every 3 weeks since the paint was down to the end of its CuOxide content.
Repainted this year, Apr2016 and about the 45 day mark, it starts to show a bit of brown slime on the sunny side waterline, but not the bottom. I don't even wipe it til I need to do the entire bottom and I only use a masonry sponge or some bunk carpet. If I see any calcified organisms trying to make a home, I gently drag an old credit card edge across it. Not sure if UltraKote is epoxy or ablative, but it works very well for me and is described as a very hard paint.
I have seen a lot of boats in the yards over the years with gelcoat blisters- it's ugly and compounds over time; lots of grind out, fair w/epoxy, sand, re-fair, re-coat, then bottom paint. Gets waaay more expensive than applying barrier coats to begin with.
 
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apogee

My name is Apogee and I am a Squidaholic
Jan 29, 2009
3,046
2,019
Bakersfield
Name
Apogee..
Boat
Boston Whaler Outrage 28 (End Game)
In 2013 I barrier coated before bottom painting on a previously unpainted '87 BWhaler. Prep was most of cost. Used 2 coats Interlux2000e, followed by Interlux Ultrakote. Boat stays in slip year round, except for outboard service evry 100-300 hrs. Usually a day or two.
Got 3 years out of that paint- it's last 3 months it needed a slime wipe about every 3 weeks since the paint was down to the end of its CuOxide content.
Repainted this year, Apr2016 and about the 45 day mark, it starts to show a bit of brown slime on the sunny side waterline, but not the bottom. I don't even wipe it til I need to do the entire bottom and I only use a masonry sponge or some bunk carpet. If I see any calcified organisms trying to make a home, I gently drag an old credit card edge across it. Not sure if UltraKote is epoxy or ablative, but it works very well for me and is described as a very hard paint.
I have seen a lot of boats in the yards over the years with gelcoat blisters- it's ugly and compounds over time; lots of grind out, fair w/epoxy, sand, re-fair, re-coat, then bottom paint. Gets waaay more expensive than applying barrier coats to begin with.
You did it the right way, regardless of the type of bottom paint used. The dedicated epoxy barrier coat is the way to start.
Ap
 
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