First time bottom paint question

john90290

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I have a 1996 adventure that's lived it entire life on a trailer and I've got it sitting in Southern California waters now year round.

I plan this and would like some feedback.

Power wash
Dewax
Sand
Petit epoxy primer for barrier coat x3
Pettit Trinidad SR x2


I've read many people don't use barrier coats, what do u guys think? I got a quote from a yard and told them that I had a fiberglass boat that had never been bottom painted and he quoted me 1400 for prep and two coats of bottom paint, no barrier?

Also, given the dry times per pettit of at least 6 hours per coat in 50 degree weather, how many days will this take? I can't imagine the boat yards down here put on one coat and call it a day? I've heard people say to wait for the barrier coat to tac off for a couple hours them hit with another coat as the coats will chemically bond?

Also, per Pettit, at 50 degrees I have to wait 120 hrs until launch after final coat?

Are these just guidelines that the company recommends but the industry disregards?

I want to do it right the first time so any guidance would be super helpful. I had an older boat that I would jut bottom paint but this Grady is so nice I want to do it justice
 

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Epoxy barrier coat is a must, especially if the boats lives in warm waters. Three coats is the way to go, then two coats of hard bottom paint(let's say blue color) then one or two coats of ablative bottom paint(let's say black color). When you see blue color you should touch up that spot with black color.
 

ocnslr

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NOTHING ELSE MATTERS said:
Epoxy barrier coat is a must, especially if the boats lives in warm waters. Three coats is the way to go, then two coats of hard bottom paint(let's say blue color) then one or two coats of ablative bottom paint(let's say black color). When you see blue color you should touch up that spot with black color.

Concur completely.

Please note that the timing of recoats of the barrier are critical for proper bonding. Same with the timing of the first paint coat after the last barrier coat.

If they don't get it right, it will likely come off in the future, in large sections.

I know from experience, and the yard had to completely re-prep the bottom and redo the barrier and all paint coats.

Brian
 

ahill

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Make sure you allow 1inch + above the noted waterline for paint to accommodate different loads.
Don't forget your motor parts that will be submerged.
Usually lower part of mount, trim apparatus and nose cone of gear box.
Treat with pettit metal primer, Q-tie ( follow directions) and top off with bottom paint.
Also add zincs to your tabs & keep an eye on the motor & tab zincs.
Stray current from adjacent boats or marina electric distribution can also cause problems.
 

john90290

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All great advice guy!! Thanks.

Looks like this will take at least 4-5 days. This is the chart for the petit primer and bottom paint.

Day 1: Prep

Power wash, dewax and sand.

Day 2.
1st coat primer wait 6 hours
2nd coat of primer, 1

Day 3
3rd coat of primer, wait 6 hours
1st coat of bottom

Day 4
2nd coat of primer

Day 5

Lauch after 24



Primer:

Substrate Temp : 50°F
To Recoat: 6hrs-14 days
To Bottom Paint: 7-10 hrs


Bottom Paint:

Temp 40°F
To Recoat: 12hrs
To Launch: 24hrs
 

ahill

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The time between coats of metal primer & q-tie is short and critical.
Check directions before starting that phase.
 

onoahimahi

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Guys - is the barrier coat really necessary? Do we not trust the gel coat? The 94 Sailfish I just acquired was lift stored and needs it's first coat of bottom paint as well.
 

ahill

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Absolutely, dewax well first.
My 272 went from trailer to water.
The yard dewaxed then applied 3 coats of epoxy barrier coat before proceeding.
 

seasick

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ahill said:
Absolutely, dewax well first.
My 272 went from trailer to water.
The yard dewaxed then applied 3 coats of epoxy barrier coat before proceeding.

For me, the question depends on the use and age of the hull. If I bought a new boat and had to paint the hull with anti-fouling, I would probably barrier coat.
On the other hand, if I bought a several year old hull that had been used AND close inspection of the hull showed no blister issues, I would be less inclined to go forward with the expense and effort to 'correctly' apply barrier coat. This is especially true if the hull had been previously bottom painted since insuring a good base for barrier coat is a bigger challenge.
There are cases where blisters wax and wane as moisture enters and exits the laminates. Barrier coating such spots can create more issues when existing moisture can't get out. Note that epoxy barrier paint can slow the development of osmosis blisters but it won't fix them. Boats that are left in the water year round are better candidates for barrier coats since any hull given enough time in the water will absorb some moisture. Boats that are seasonally stored in the open or in a storage facility will 'dry' out during that storage.
Gel coat as mentioned is a pretty good moisture barrier. If you sand away the gel coat or damage it, a barrier coat can help. I guess what I am saying is that for me there is no definite yes or no for barrier coating.
My personal experience with barrier coating ( Inter-protect 2000) is that even with meticulous prep, some chipping of the paint will occur over time. I am not sure why but each season I have some chipped areas to spot repair.
 

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I don't understand why it's necessary to apply hard bottom paint over a barrier coat in between the ablative. I don't know what color Pettit's is, Interlux was or is grey. When the black ablative wears off the grey barrier shows through on mine. Money saved on the hard.
 

seasick

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Shutterbug said:
I don't understand why it's necessary to apply hard bottom paint over a barrier coat in between the ablative. I don't know what color Pettit's is, Interlux was or is grey. When the black ablative wears off the grey barrier shows through on mine. Money saved on the hard.
I agree.
 

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Shutterbug said:
I don't understand why it's necessary to apply hard bottom paint over a barrier coat in between the ablative. I don't know what color Pettit's is, Interlux was or is grey. When the black ablative wears off the grey barrier shows through on mine. Money saved on the hard.
When you sand the ablative paint to apply the new one, if you don't have the hard under it you will be sanding the barrier coat, besides gives the extra protection and you only do it once(the hard).
 

seasick

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NOTHING ELSE MATTERS said:
Shutterbug said:
I don't understand why it's necessary to apply hard bottom paint over a barrier coat in between the ablative. I don't know what color Pettit's is, Interlux was or is grey. When the black ablative wears off the grey barrier shows through on mine. Money saved on the hard.
When you sand the ablative paint to apply the new one, if you don't have the hard under it you will be sanding the barrier coat, besides gives the extra protection and you only do it once(the hard).

You don't need to sand that agreesively. Just a light sanding or no sanding at all for many ablatives. I use a scotchbrite pad. If you sand hard enough, you can sand through hard also.
The hard will add drag and weight too and that can affect performance. I just don't see a need for a hard coat under ablative.
 

john90290

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Emailed Pettit about dry times. See response ( and my question ) below. Thought this might help others.


Thank you for the e-mail. As long as the paint does not come off on your
finger then you can recoat. Use that as your guide, as dry time are
effected by different elements


Check out the new www.pettitpaint.com !

Joe Petrocelli
Customer Service
Pettit Paint
Ph 973-776-8274
Fax 973-625-8303


To: <jpetrocelli@kop-coat.com>

Date: 02/21/2013 10:59 AM

Subject: Ask The Expert Question

Submit Date..: 2/21/2013 10:59:03 AM

Question.....: Bottom painting 22 foot fiberglass boat. Read all
instructions. Doing the Dewax and barrier coats then Trinidad sr. Read all
the data sheets. Temps will be low of 50 high of almost 70. Want is the
minimum drying time for epoxy , Pettit 4700, between coats. Data sheet
says 6 hours but I've read to use you thumb to test the paint. If it leaves
a fingerprint and does not take up paint, it's ready for recoat?

Looking for real world advice or should I stick to the book.
 

john90290

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Well, after all of the fact checking, research and advice from you kind folks, this weekend it begins...

Picked a nice weekend as well, a little heat wave on the way, temps in the 70's and 80's for the next two days!

Will take pics and update.
 

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john90290

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Third coat of bottom paint done today. Trinidad sr going on in the morning. I'm tired. The dewaxing solvent fumes are unreal in the worst possible way.
 

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john90290

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Third coat of bottom paint done today. Trinidad sr going on in the morning. I'm tired. The dewaxing solvent fumes are unreal in the worst possible way.
 

john90290

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All done!

Lessons learned:

Planning everything out was key. It allowed for the least amount of wasted product and time Specifically the barrier coat as it requires mixing and depending on dry time, you may end up with material you cannot use after its effective pot life.

Have friends. My buddies helped sand and dewax. Made the project doable in 3 days.

Don't drive after dewaxing. That solvent is powerful!!! Even with the proper 3M masks we all felt a little buzzed off the fumes. Getting rid of the rags asap was also a plus as they tend emit the odor until they dry. We laid them out downwind to dry out then disposed of properly.

Don't be the guy that tapes the line (that was me). No one wanted to do it because you'd be the guy ultimately responsible for the final product. It came out really good but not great. If I had to do it again, I would have pulled the tape after the barrier coat in order to see what the line looked like and then re-taped to adjust any small errors.

Have a list of other projects to complete during dry times. We ended cleaning up all the old wiring plumbing in the bilge. Turned out the bilge was direct wired to battery one so when we ran on two, we had no bilge. No big deal unless we figured it out 25 miles off shore while taking on water.

Now I just have to stick it in the water....

Hope this helped a few folks out there.

-John
 

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john90290

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All done. Thought I would post a conclusion to my bottom paint adventure on my adventure.

Proceeded as detailed above and it's been I the water about a month. Minimal growth and no paint peeling off in sheets. That Pettit two part epoxy barrier coat is insane. Got some on my bench made knife and it won't come off!

Thanks for all who provided guidance.