Bottom Paint on Aluminum Boat

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jrogers
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Bottom Paint on Aluminum Boat

#1

Post by jrogers »

I did a search, and didn't really get an answer to my question, so here it is. Should I bottom paint my boat, and if so, with what? What are the impacts from bottom paint in regards to performance? My boat is a 2009, and currently is bare aluminum everywhere,including the bottom. I am contemplating adding bottom paint, since it seems it is sitting in the salt water more and more each year. Last year I would say that it was in the water 4 or 5 months, and only pulled out to be cleaned three times. Performance was taking a hit from the growth where I was getting less than double the fuel economy of the outboard guys (ouch!). Someone recently told me that they added bottom paint, and had the exact same top end speed after adding it as before, and the installer expected even a bit better performance. They used EPaint SN-1 with the appropriate primer. Is this a good choice, or is there a better one? It seems like I should be able to go 4+ years up here without any reapplication, and that being on the trailer, especially in a cold climate is not a problem. Any other issues to worry about, or should I do this?
Jim

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Chaps
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Re: Bottom Paint on Aluminum Boat

#2

Post by Chaps »

Besides discouraging marine growth the main reason to bottom paint alloy boats IMO is to reduce the likelihood of hull plate pitting due to galvanic corrosion. I get unpainted, trailered boats in my shop all the time that are showing significant signs of deterioration in spite of what looks like adequate anode protection. A proper paint job will cloak the hull in an impermeable epoxy jacket that forever isolates the hull from seawater contact and the stray corrosive currents commonly found in the waters of public marinas. The anti-foul paint then goes over that.

Speed and efficiency losses associated with bottom painting is typically the result of poor hull prep and haphazard coatings application. If it looks like it was slopped on with a bristle brush your performance is going to suffer. If you are going to do it hire someone willing to do a good job.

Pettit Vivid is tougher than epaint and has much better anti-foul properties
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jrogers
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Re: Bottom Paint on Aluminum Boat

#3

Post by jrogers »

Bob,

Thanks for the advice. I looked at this product, and I see that it comes in colors. Have you done anything except black on a bare aluminum boat? I was thinking something like their 4 white / 1 black may look stealthy, like the natural gray of the aluminum, but Black would probably be the default color on my boat, especially since I have black accents already.
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Re: Bottom Paint on Aluminum Boat

#4

Post by Chaps »

I think gray would look nice on an aluminum boat but everyone opts for black, probably because black hides crud build-up at the waterline better than any other color. Crud build up defined as all the non-organic muck floating around that collects on a hull that is not rejected by the biocide in the paint. That said, your waters up there might be clean enough that the bathtub ring wouldn't be an issue.

This is a plastic cruiser that wanted gray, its about 3:1 Vivid white/black as I recall. The outdrive is a little darker, I tried to match the volvo gray factory paint. Yeah, that's bottom paint on the drive.
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Re: Bottom Paint on Aluminum Boat

#5

Post by Challenge »

I've tried Epaint for a few years now on my small boat and I'm not all that impressed... especially with the second season results. Next time I will be switching.

Chaps, can Vivid go over the existing paint I think the boat has Tri-Lux 33 (new boat to me)?? also do you use Vivid free? or their regular product?

thanks for all your help

Rick
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Re: Bottom Paint on Aluminum Boat

#6

Post by Chaps »

I use the regular Pettit Vivid which uses copper thiocyanate as the biocide (fully compatible with aluminum). Vivid Free has been discontinued and replaced with Pettit Ultima Eco which I've heard good reports on BTW and I will likely switch over to as the copper ban comes into effect here in Washington.

Trilux 33 also uses copper thiocyanate but I find the resin system of that paint to be way inferior to Vivid and the percentage of biocide they add in must be minimal because barnacles show up on that stuff (at least around here) during the first season. I won't put it on.

Vivid can be applied over existing paints as long as the old paint is clean and any soft, chalky and deteriorated paint has been removed by a strong pressure wash and/or a vigorous detergent scrub. Let the paint dry out then do a quick power sand to smooth out the rough spots and to abrade any exposed metal. Best adhesion for the new paint will be accomplished by first applying a tie-coat primer like Seahawk 1277 over your now ready to paint surface. Its inexpensive, easy to apply, dries fast and insures your new expensive anti-foul paint will never peel off. If your boat has epoxy under its existing paints and it is worn through to metal anywhere its a good idea to patch it back in but the 1277 primer is adequate for that purpose if you apply a couple of extra coats of it on those bare spots.
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Re: Bottom Paint on Aluminum Boat

#7

Post by jrogers »

What sort of prep would you recommend for a bare aluminum boat that has been in and out of the water for 6 year? Do you recommend painting the outdrive? I think Volvo says not to do that, but the outdrive does get some growth on it, although this may not effect performance since it is all out of the water when running.
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Re: Bottom Paint on Aluminum Boat

#8

Post by Chaps »

Jim, I'm sure with all the alloy boats up there the yards know what to do. Basically you mask with a heavy vinyl tape, sandblast, apply an anti corrosion epoxy, a barrier coat epoxy then your anti-foul paint. Here is an old post showing the steps. I've changed up a couple of the products I use now but this covers the basics.

Bottom paint on alloy boat

Painting the drive is up to you. If yours is the one with the plastic cover then a special system is used
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Re: Bottom Paint on Aluminum Boat

#9

Post by goatram »

Tomorrow I will pull my boat after 6 months in Westport in that time it was removed twice. Once for a trip home to fix a minor issue and do a 100hr, the second to lower the motors. Mine was painted by Chaps last year. I had to do some repair touch ups this last spring. Tomorrow I will spray bleach on the bottom when pulled and then steam clean it when I get it home. I did have to scrub down the Underwater Lights (Amphibians) on the Stern a couple of times. They are supposed to have a coating to stop Marine Growth but they Failed! Pictures to follow of what it looks like when pulled and how much work to get her bottom pretty again. :rotfl:
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Re: Bottom Paint on Aluminum Boat

#10

Post by Chaps »

John, I can't be held responsible for the scratches and scuffs Miss Eliza's bottom paint is going to show as a result of all the collisions, sideswipes and sinkings of those Parkers, Defiances and Grady Whites you had a hand in destroying out on the tuna grounds this year. Marine growth is one thing but no paint system can endure the aquatic destruction derby you rained down on the clorox bottles this past season.

:beer:

Just for the record this is what she looked like when you took her home a couple of years ago
IMG_0685.jpg
How would you like to see this coming at you at about 35 knots as you are trolling along in your C-Dory?
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Re: Bottom Paint on Aluminum Boat

#11

Post by Gypseas »

Chaps you do an amazing job, wish you lived closer :thumbsup:

Thanks for posting that step-by-step. I used ep2 paint in the past and wasn't impressed with it, this time vivid it is.

cheers
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Re: Bottom Paint on Aluminum Boat

#12

Post by Chaps »

Thanks, I like doing this stuff properly. BTW, can you get Vivid in Canada now? I was in a marine store in Sydney awhile back and the owner was saying that they can't get it as well as a lot of other good paints. Environmental regs gone wild!

Run your boat down, I'll haul you out and paint it with some good stuff
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Re: Bottom Paint on Aluminum Boat

#13

Post by kdubinwa »

Chaps wrote:John, I can't be held responsible for the scratches and scuffs Miss Eliza's bottom paint is going to show as a result of all the collisions, sideswipes and sinkings of those Parkers, Defiances and Grady Whites you had a hand in destroying out on the tuna grounds this year. Marine growth is one thing but no paint system can endure the aquatic destruction derby you rained down on the clorox bottles this past season.
Hey Bob,

I'm not sure what to make about this vicious attack on John?? Afterall it was John who introduced me to you for my last little blast job and John has been helping me navigate build options on my new North River Death-Ship. From everything I have heard, your bottom paint job is a license to ram anything plastic.

I'm headed your way again, but now I'll have to be on the lookout for some testy warranty exclusions....

Kurt
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Re: Bottom Paint on Aluminum Boat

#14

Post by Gypseas »

Chaps wrote:Thanks, I like doing this stuff properly. BTW, can you get Vivid in Canada now? I was in a marine store in Sydney awhile back and the owner was saying that they can't get it as well as a lot of other good paints. Environmental regs gone wild!

Run your boat down, I'll haul you out and paint it with some good stuff
This is what I can get up here http://trotac.ca/ look for the catalogue and search for paints.

What would you charge for a 24 ft (30inch pod). PM if you would like


Cheers,
Adrian
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Re: Bottom Paint on Aluminum Boat

#15

Post by Chaps »

Gypseas wrote:
This is what I can get up here http://trotac.ca/ look for the catalogue and search for paints.

Adrian
That Trotac catalog only shows three paints and none of them are aluminum compatible. I looked at a couple of other on-line marine product suppliers in Canada and only found two products, Interlux Trilux II and Aquaguard Alumi-Koat that can be bought up there and can be applied to alloy. Between those two I'd probably recommend the Aquaguard though with faint praise.
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Re: Bottom Paint on Aluminum Boat

#16

Post by Chaps »

Hey Bob,

I'm not sure what to make about this vicious attack on John?? Afterall it was John who introduced me to you for my last little blast job and John has been helping me navigate build options on my new North River Death-Ship. From everything I have heard, your bottom paint job is a license to ram anything plastic.

I'm headed your way again, but now I'll have to be on the lookout for some testy warranty exclusions....

Kurt
Kurt, John, like his boat, has very thick skin. Now that I know he is advising you on setting up your new boat we'll have to be sure to verify your waterline as it will likely be setting a lot lower in the water than planned for by the manufacturer :rotfl:
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Re: Bottom Paint on Aluminum Boat

#17

Post by goatram »

Chaps wrote:
Hey Bob,

I'm not sure what to make about this vicious attack on John?? Afterall it was John who introduced me to you for my last little blast job and John has been helping me navigate build options on my new North River Death-Ship. From everything I have heard, your bottom paint job is a license to ram anything plastic.

I'm headed your way again, but now I'll have to be on the lookout for some testy warranty exclusions....

Kurt
Kurt, John, like his boat, has very thick skin. Now that I know he is advising you on setting up your new boat we'll have to be sure to verify your waterline as it will likely be setting a lot lower in the water than planned for by the manufacturer :rotfl:
What a Smart A$$ you are today Bob. I got the Cleaning Lady here at work Giving me a hard time as well. SOB! :gun3:
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Re: Bottom Paint on Aluminum Boat

#18

Post by kdubinwa »

Chaps wrote:
Hey Bob,

I'm not sure what to make about this vicious attack on John?? Afterall it was John who introduced me to you for my last little blast job and John has been helping me navigate build options on my new North River Death-Ship. From everything I have heard, your bottom paint job is a license to ram anything plastic.

I'm headed your way again, but now I'll have to be on the lookout for some testy warranty exclusions....

Kurt
Kurt, John, like his boat, has very thick skin. Now that I know he is advising you on setting up your new boat we'll have to be sure to verify your waterline as it will likely be setting a lot lower in the water than planned for by the manufacturer :rotfl:
LOL... no doubt on John's thick skin.

I'm guessing the waterline will be about 6 inches below the gunwale by choice. Loads of toys, munitions, etc, and drafting deep so the plastic boats stay down when put down.
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Re: Bottom Paint on Aluminum Boat

#19

Post by MacGyver »

jrogers wrote:I did a search, and didn't really get an answer to my question, so here it is. Should I bottom paint my boat, and if so, with what? What are the impacts from bottom paint in regards to performance? My boat is a 2009, and currently is bare aluminum everywhere,including the bottom. I am contemplating adding bottom paint, since it seems it is sitting in the salt water more and more each year. Last year I would say that it was in the water 4 or 5 months, and only pulled out to be cleaned three times. Performance was taking a hit from the growth where I was getting less than double the fuel economy of the outboard guys (ouch!). Someone recently told me that they added bottom paint, and had the exact same top end speed after adding it as before, and the installer expected even a bit better performance. They used EPaint SN-1 with the appropriate primer. Is this a good choice, or is there a better one? It seems like I should be able to go 4+ years up here without any reapplication, and that being on the trailer, especially in a cold climate is not a problem. Any other issues to worry about, or should I do this?

I just found this old thread. I've been reading up on e-Paint SN-1. If you still have question several of them can be answer by going to there web site.

This may sound odd to some of you, one thing that impressed me about e-Paint is.... They mention possible problems using SN-1, on a trailer hot temperatures soften the paint, UV light, and washing down the hull effecting service life. Most manufacture only mention the good things. http://aluminumalloyboats.com/images/sm ... umbsup.gif

BTW, Painting the hull with Antifouling paint will not fix a corrosion problem. It will slow the corrosion down by reducing the size of the foot print in the water the zincs are protecting. If you do not also reduce the size of the zincs you could end up with corrosion cause by having to much zincs. http://aluminumalloyboats.com/images/sm ... nghead.gif When in doubt have the boat tested to determine the location and sq inches of zincs needed.

If your boat is a slip Queen and you do not want to deal with cleaning the bottom SN-1 sounds like
it is a excellent product.

I've copy some of the information pertaining to your questions I think you would like to know.
http://www.epaint.com/index.php?id=19&prod_id=19

Product Description:
ePaint SN-1 is the only copper and tributyltin-free alternative antifouling paint for heavy duty applications.  Formerly only available for use by U.S. government agencies, SN-1 is EPA registered and now approved for use on commercial vessels and commercial application.    SN-1 is recommended for boats in fresh and salt water.  SN-1 offers excellent antifouling protection in even the harshest marine environments.

Technical Overview:
Average Service Life: Affected by number of coats, color choice, boating useage, available sunlight and water temperatures; average service life for boats in temperate waters is 18-22 months, boats in tropical waters is 12-18 months with three full coats and additional coats around waterline, leading edges, and high wash areas
Recommended Number of Coats: 2 or 3 full coats with additional around waterline and high wash areas for longest service life.

Not Recommended For: Trailered boats in hot climates as paint may soften slightly at temps above 90oF, digging into rollers and pads; over very soft ablative paints, bare metal (prime first); application by non-commercial painters

Considerations:
> Due to the photoactive nature of ePaint SN-1, additional coats around the waterline are strongly recommended to extend service life.
> SN-1 is thermo-plastic by nature and hot temperatures above 90oF can soften SN-1 slightly, particularly on aluminum boats in full sun, which can cause paint to dig into pads and straps.  If SN-1 is to be launched in hot climates, consider launching boat in the morning before full sun and temperatures climb and placing plastic sheeting between pads and straps before lifting. The thermo-plastic nature of SN-1 has no effect on antifouling performance and paint will immediately harden when place into service of cooler waters.
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Chtucker
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Re: Bottom Paint on Aluminum Boat

#20

Post by Chtucker »

PMed Bob about some advice on raising my waterline.

My Epaint has been OK in freshwater, but I need to go up an inch or 2.

I asked the Pettit rep at the show and now am more confused than when I started.
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Re: Bottom Paint on Aluminum Boat

#21

Post by ReelSong »

Bob, what are you using for epoxy coat, I used a product called metal loc. I'd like to put my bottom paint on while she's upside down in a few weeks but want to make sure I use the best base coat.
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Re: Bottom Paint on Aluminum Boat

#22

Post by Chaps »

My prep is sandblast and from there I go 2 coats Pettit Alumaprotect epoxy for anti-corrosion properties (but it is very thin), then 3 coats of Interlux 2000E epoxy barrier coat for moisture isolation and building a base coat for (usually) Pettit Vivid for anti-foul. If you don't want to blast or do a thorough sanding to generate a profile on the metal then you'll want to do an acid etch treatment so your epoxy system has something to grab on to. Blasting is an order of magnitude better than acid etching IMO but not always easy to make happen.
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Re: Bottom Paint on Aluminum Boat

#23

Post by ReelSong »

Bob l do plan on blasting the outer hull while it's upside down. Thanks for the info
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Re: Bottom Paint on Aluminum Boat

#24

Post by Chaps »

BTW, try and get the first coat of primer on the freshly blasted surface pretty quickly before oxidation starts to occur, same day at least and preferably within the first hour or two. If you mask your waterline with heavy vinyl tape and your blaster can do his job without tearing up the edge of the tape then you can use the blast mask also as your paint mask which means you can apply your primer quicker.
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Re: Bottom Paint on Aluminum Boat

#25

Post by Chtucker »

Just a follow up..

I would not use E Paint. While I don't have any real fouling, I also burned through the paint in less than 130 hours running and keeping the boat in fresh water.

I am having Armstrong fix the waterline. I went with the Aluma Protect, Pettit Epoxy and then another few coats of E paint. Next time it will be something else.
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