Epoxy Barrier & Bottom Painting How many Coats

[Gazmn]

Ok. New motor is paid for... waiting for fair weather & prop testing. Boat has been out of my driveway all off season Miss her...

So rather than preparing for "Miss Ollie's" homecoming I just commissioned a complete bottom reno: sand blasting the bottom coat layers, epoxy barrier coat & new bottom coat, probably the hybrid Pettit. $65/ft. 1 coat each... What do you think. Is that enough? should I pay/ press for more coats. & of what...

I was considering doing this at home on my own... But I'd have to get: stands, wet or dry blasting pi$$ ed neighbors A couple good suits, 6mil plastic & gear... & the mess...

Basically, I'm paying for the convenience. Anything I should watch out for.

While always bottom painted. It wasn't epoxy barrier coated, I keep it on a mooring ball for the season. God knows if hull got saturated & contributed to slow motoring speeds. But this would be another variable to correct.

[RobertB]

If you are worried about water saturating the hull, this needs to be dealt with before the epoxy barrier coat. A series of small holes drilled in the hull will show if you have water. And if so, will need some time to drain. The holes are easily filled.

[Ixneigh]

Have to respectfully disagree with above. I wouldn't drill any holes. That's for serious cases of obvious water saturation.
If there is no obvious problems and this is a preventative measure only, just prep the bottom and paint. The boats been out of the water long enough to dry out.
Apply at least two if not three, rolled on coats of epoxy. Apply it like you own stock in the company.
Follow whatever dry times listed. Thickness is what you are after. They tell you how thick they want the coating on the can. If you farm this job out , make sure you either trust the guy or supervise. This isn't a job for the local handy man.
Also note, sandblasting may not be as good as just grinding the hull. You can skirt the boat with plastic and do that yourself if you have or can rent an air tool and compressor. Electric tools work but are less preferable. When I did this job I had the boat set on stands at a local yard. That was worth the cost.

I used the interprotect system, for what it's worth. The boat stays on her mooring all season. So far so good. (Three years old)

Ix

[RobertB]

No argument, I was only suggesting serious measures if there was a reason to expect the hull is saturated. A good indication - if it is heavier than it used to be. Once the epoxy is on, the hull is sealed - extra ballast is now a permanent feature. Oh, and the multiple coats is a good suggestion.

[Gazmn]

Have to respectfully disagree with above. I wouldn't drill any holes. That's for serious cases of obvious water saturation.
If there is no obvious problems and this is a preventative measure only, just prep the bottom and paint. The boats been out of the water long enough to dry out.
Apply at least two if not three, rolled on coats of epoxy. Apply it like you own stock in the company.
Follow whatever dry times listed. Thickness is what you are after. They tell you how thick they want the coating on the can. If you farm this job out , make sure you either trust the guy or supervise. This isn't a job for the local handy man.
Also note, sandblasting may not be as good as just grinding the hull. You can skirt the boat with plastic and do that yourself if you have or can rent an air tool and compressor. Electric tools work but are less preferable. When I did this job I had the boat set on stands at a local yard. That was worth the cost.

I used the interprotect system, for what it's worth. The boat stays on her mooring all season. So far so good. (Three years old)

Ix

Thanks guys. I'm looking at sand blasting only because of the Spray Rail Mod I did a few years back. I want it clean; that & the keel guard - that has an 8" gash has to be cleaned out. It's the yard's sub contractor so I hope he's good in the nooks & crannies like the centerboard too. Once it's stripped, we'll take a look see as to what's been going on underneath re: water absorbtion & necessary fill ins. Speaking of which, my hull is a transitional '97. By this time they had stopped with the underneath fill of the earlier models. I have a ~ 7x4x 2"D closed indent a little past the centerboard. It would correspond to the hump step inside the cabin. Do all hulls have this or should I look to fill it in too?

I'm gonna lobby for 3 coats epoxy + 2 black & "pucker up" when he gives price quote. If I can work / paint in this yard I'll do it myself. But I don't get that feeling regarding bottom work here. He did mention the bottom weight all of this would add, too; I'm guessing 60lbs. But this was more to dissuade me & scale down his applying layers.

[yukonbob]

Make sure they put on what you ask and are paying for Gaz. The old pay for three and get one deal Same for the anit-foul.

[Sumner]

If you had blisters you would see them and you would need to open them up and let them thourly drain. That took about 7 months on the Endeavour and it was in the yard on stands.

On the barrier paint, epoxy, you need to put on what the manufacture says you need for it to work not what anyone thinks. I used Sea Hawk's Tuff Stuff and it goes on with a thicker coat, build, vs. say Interlux. Sea Hawk recommends a min. of 2 coats and 3 is the upper coats. I put 2 on the Mac and 3 on the Endeavour. I believe for the Interlux you need 4 to 6 to achieve the same build and is what they recommend but read the product applications. Sea Hawk could cost less as the labor goes down.

We had the Endeavour sand blasted to remove all old paint. The guy that did it does boats, period, and has the equipment designed for doing boat bottoms. When he is done there is just a blush of the paint left and that will be removed sanding prior to the barrier paint and during blister repair if you have to deal with that. On the Mac there were no blisters and no previous paint so sanded with 80 grit on a DA sander, know what you are doing if you use one. Saw Hawk wanted the 80 grit sand scratches to achieve a good initial mechanical bond between the pain and the hull. From that point until you are done with the bottom paint you need to put on coats of paint within the manufacture's time window between coats to achieve a chemical bond between them. People talk about paint pealing off later in sheets did not adhere to these time windows. They can be a pain to achieve and it is better to go over night between epoxy coats vs. between the barrier paint and the bottom paint and between coats of bottom paint.

On both boats I changed colors part way though with the bottom paint so in the future when it wears through one and you see the next it is time to repaint. I have all of this on the site, both on the Endeavour side and the Mac side.

One final thing. I would never let someone sandblast the bottom that does cars, frames, trailers, etc. unless I really trusted them and I mean 'really' trusted them to know what they are doing.

This is not a hard job but one that needs to be done right or you are throwing money away and will have a bigger more expensive problem to fix down the road. Do what the manufacture of the paint you are using and you will get it right,

Sumner

============================
2015 To the Bahamas and back -- I hope

Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

[Gazmn]

Make sure they put on what you ask and are paying for Gaz. The old pay for three and get one deal Same for the anit-foul.

Yeah I will - It's a Great Deal - for 150 bucks more I can get my name on a bridge... In Brooklyn

Sumner:
Firstly, I hope your trip is going well & you remain safe and well. We're all keeping up with your excellent blog & rooting for you

Secondly, I was also reading your blog on your bottom coating.Thanks for the details. I like the Sea Hawk & gonna check out my options tomorrow.

I'll make this my mantra:

On the barrier paint, epoxy, you need to put on what the manufacture says you need for it to work not what anyone thinks. I used Sea Hawk's Tuff Stuff and it goes on with a thicker coat, build, vs. say Interlux. Sea Hawk recommends a min. of 2 coats and 3 is the upper coats.

Thanks Guys

[seahouse]

Manufacturers usually recommend a mil thickness for the application of epoxy that is effective for that product, particularly when working with the barrier coat. That is the thickness as measured in thousandths of an inch, so 15 mil is 0.015", for example, which can be measured with a vernier or dial caliper or micrometer. It might take 4 thick coats to get you there, or 5 thinner coats, using example numbers I made up. With normal paint (say even for your house, latex or enamels that are one-part) using more but thinner coats gets you a better job, for a number of reasons, but a major one is that they (loosely) dry by evapouration of the solvents from the surface, so a thick coat can skin over and impede the hardening of the layers below.

That is not so with epoxy, which hardens by a chemical reaction of the two parts that you mix together, regardless (within reason) of the thickness. After the first coat, you can put them on thicker (assuming the coat is viscous enough to allow it) to finish the job in fewer coats with no penalty in performance. It's more the mil thickness, than the number of coats that it takes to get there that is important. If you arrive at the job site just as they peel off the masking tape you can take a direct and accurate measurement of the total mil thickness applied from it. (Subtract the measured tape thickness from the fully-painted edge of the tape thickness).

Like Sumner, I applied black beneath the blue anti-foul so I could tell when the blue on top was wearing out. (Both over grey barrier). Coming into the 5th season now, and I have seen neither hide nor hair of the black layers yet, other than scarring from launching, which I touch up (I deliberately keep a small quantity of paint at the end of the job for this). I power wash heavily on the end of season take-out, but avoid scrubbing or friction other than that.

Some of the effectiveness of the anti-foul is lost when the surface dries out over the storage season, but I have not noticed any decrease in effectiveness as compared to the first season.

Good luck, Gaz.

[Gazmn]

Thanks Seahouse
I also researched your bottom job & was again Very Impressed & Appreciative of the work you put into your boat & sharing. I really like the support horses you made & appreciated their function & how they let you cover most of your boat & catch up with the patches later on. Your detail, & Sumners, is FANTASTIC & you guys input & craftsmanship is such a high level. Inspiring & makes me wanna up my game

I wish I had the room interior or exterior that you guys have.To work on your Macs. I know you did yours before redoing your backyard & boat pad. I don't have enough room to do this around the house & take care of the mess. So I'm kinda stuck with using a yard, this time

Regarding next time, I hope this lasts for next 7 years. So I better put it on thick

So I pretty much have to delegate to a yard. & since I'm already in one for the motor, I'm vested & hope they'll meet me halfway regarding layers. I like your pigment variations so you know what you're down too

[dlandersson]

Did the barrier and then two anti-foul (alternating black and white so I can see the wear. Two years now, stil looking good.

Manufacturers usually recommend a mil thickness for the application of epoxy that is effective for that product, particularly when working with the barrier coat. That is the thickness as measured in thousandths of an inch, so 15 mil is 0.015", for example, which can be measured with a vernier or dial caliper or micrometer. It might take 4 thick coats to get you there, or 5 thinner coats, using example numbers I made up. With normal paint (say even for your house, latex or enamels that are one-part) using more but thinner coats gets you a better job, for a number of reasons, but a major one is that they (loosely) dry by evapouration of the solvents from the surface, so a thick coat can skin over and impede the hardening of the layers below.

That is not so with epoxy, which hardens by a chemical reaction of the two parts that you mix together, regardless (within reason) of the thickness. After the first coat, you can put them on thicker (assuming the coat is viscous enough to allow it) to finish the job in fewer coats with no penalty in performance. It's more the mil thickness, than the number of coats that it takes to get there that is important. If you arrive at the job site just as they peel off the masking tape you can take a direct and accurate measurement of the total mil thickness applied from it. (Subtract the measured tape thickness from the fully-painted edge of the tape thickness).

Like Sumner, I applied black beneath the blue anti-foul so I could tell when the blue on top was wearing out. (Both over grey barrier). Coming into the 5th season now, and I have seen neither hide nor hair of the black layers yet, other than scarring from launching, which I touch up (I deliberately keep a small quantity of paint at the end of the job for this). I power wash heavily on the end of season take-out, but avoid scrubbing or friction other than that.

Some of the effectiveness of the anti-foul is lost when the surface dries out over the storage season, but I have not noticed any decrease in effectiveness as compared to the first season.

Good luck, Gaz.

[OverEasy]

Hi All!

Boy is this a ‘long’ thread! 8+ years!

It’s a good thread too! Great advice!

When we purchased Over Easy one of the previous owners had applied an ablative barrier coating at some point in the distant past.
We thought it might be ‘good enough’ for or first season on the South Carolina estuaries back in 2021.
(We planned on getting the hull wet sanded and new epoxy & ablative when we hauled out.)
Nope The old coating was definitively not up to the task.
We had a lot of marine growth all along the bottom…a veritable marine forest! Yuck

Our local boat yard did an excellent job of wet blasting and cleaning the hull.
2 coats of bottom epoxy and 2 coats of ablative on the hull rudders and swing keel.
So it’s now the end of summer 2023 and it’s been holding up great!
Money well spent as it would have been ‘gawdafulmess’ to have tried doing it ourselves.
The weather cooperated and the yard had it all done in a week.

So far the ablative has been holding up well and doing it’s job in fresh and salt water.

Ablative, by its very basic functional description, sheds as one moves through the water.
As we’ve been operating in trawler mode we do a fair bit of motoring enjoying both the go-slow and go-fast capabilities of our Mac26X.
The yard and other resources have mentioned that one should consider Re coating the ablative every two years when in regular use.
As such we’ll take a good look at our bottom when we haul out at the end of season to check it over.
But so far it’s really been doing a great job of shedding marine growth and giving us a nice clean hull.
We used the Interlux Products.

Best Regards
Over Easy