SailNet Community

SailNet Community (http://www.sailnet.com/forums/)
-   Gear & Maintenance (http://www.sailnet.com/forums/gear-maintenance/)
-   -   Bottom paint flag coat theory vs. reality (http://www.sailnet.com/forums/gear-maintenance/96492-bottom-paint-flag-coat-theory-vs-reality.html)

4arch 02-09-2013 09:22 AM

Bottom paint flag coat theory vs. reality
 
I've read in several books, magazines, and forum posts that when applying ablative bottom paint it's wise to apply an undercoat of a contrasting color to act as a "flag" to indicate when the topcoat is worn through. I'm curious as to what kind of experiences people have had with this method in the real world?

Looking around boatyards at boats awaiting spring painting, I haven't seen boats with half worn-through top coats revealing contrasting color paint. In my own experience, the ablative paint loses all effectiveness and must be recoated well before it wears off. In the interest of minimizing paint buildup, it seems that it might be better to skip the flag coat and and to just apply single thin coat of ablative directly over the barrier coat.

I'd appreciate people's thoughts and experiences on this. I just had my boat's bottom soda blasted and plan to barrier coat in the spring. Since I'm starting over completely I want to do things right and keep from getting to the point of having the extreme buildup I had before.

klem 02-09-2013 09:35 AM

Re: Bottom paint flag coat theory vs. reality
 
Personally, I think that you can tell whether it needs to be redone without a flag coat. The first year or two after you strip the bottom you might see a bit of the barrier coat at the next haulout but after that, most people will have enough paint buildup that they would never see a flag coat again unless done yearly.

We essentially have a flag coat as the PO switched bottom colors for asthetic reasons. We see a little bit of it every season but it doesn't change our painting habits.

Maine Sail 02-09-2013 11:19 AM

Re: Bottom paint flag coat theory vs. reality
 
Quote:

Originally Posted by 4arch (Post 987906)
I've read in several books, magazines, and forum posts that when applying ablative bottom paint it's wise to apply an undercoat of a contrasting color to act as a "flag" to indicate when the topcoat is worn through. I'm curious as to what kind of experiences people have had with this method in the real world?

Works tremendously well and allows you to not put on too much paint and avoids build up.

Quote:

Originally Posted by 4arch (Post 987906)
Looking around boatyards at boats awaiting spring painting, I haven't seen boats with half worn-through top coats revealing contrasting color paint.

I see it all the time. My own boat with a black bottom has a few spots every year of red exposed. I usually rough up those areas with Scotch-Brite or my pressure washer and re-launch.


Quote:

Originally Posted by 4arch (Post 987906)
In my own experience, the ablative paint loses all effectiveness and must be recoated well before it wears off.

That has not been my experience at all. A simple scuff in the spring gets it going again though I've done nothing and had it work perfectly. Are you buying "multi-season co-polymer ablatives?


Quote:

Originally Posted by 4arch (Post 987906)
In the interest of minimizing paint buildup, it seems that it might be better to skip the flag coat and and to just apply single thin coat of ablative directly over the barrier coat.

I went with a HOT COATED red layer, 1/4" roller, then another thin coat of black with a 3/16" roller. It's been six years and we have zero paint build up.. Hot coating is CRITICAL for the first layer to adhere and bond to the barrier coat. It usually requires one guy rolling the last coat of barrier and the next guy rolling the first coat of bottom paint a few minutes behind him or "thumbprint" dry. In warm weather thumb print dry happens fast....

The ONLY glitch we had was that I allowed the Pettit rep to talk me into Hydrocoat. HUGE, HUGE mistake. It failed to perform, failed to "ablade" and it all had to come off. I went back to Ultima SR-60 and am back to great paint performance.......

Quote:

Originally Posted by 4arch (Post 987906)
I'd appreciate people's thoughts and experiences on this. I just had my boat's bottom soda blasted and plan to barrier coat in the spring. Since I'm starting over completely I want to do things right and keep from getting to the point of having the extreme buildup I had before.

The last boat I did before this one was in 1997 and as of three years ago the bottom still looked perfect. It was hot coated and used a tracer color. The current owner kept up with the 3/16" roller only applying when the paint got thin.

I would highly recommend Interprotect 2000E.. It is a tremendous product that allows for LONG open times between chemical bonds barrier to barrier.... Also comes in white and gray so you can alternate to make sure you have good film thickness.

Please also be sure your hull is DRY. The biggest mistake people make is coating a substrate with too much moisture in it... Usually best to strip it in the fall and let it sit all winter to dry before barrier coating.

The biggest mistake people often make with ablatives is painting them every year as if they were hard paints. This defeats the purpose of using an ablative. If your coats are thin enough then you may need to paint each year.. This spring I only have a couple of areas to touch up, leading edge of keel, bow, rudder and around the prop.... I used a 1/4" roller last year after removing the Hydrocoat (what a PITA). I can get two+ seasons out of one coat with a 1/4" roller.

lancelot9898 02-09-2013 11:59 AM

Re: Bottom paint flag coat theory vs. reality
 
Hi Maine,

I'm going to be hot coating my bottom paint to 2000E this coming spring and noticed that you suggest doing it quickly after applying the 2000E. The interlux guy over on yachtpaint.com says that waiting the 3 hours is OK for getting that chemical bond. I think it needs to be applied quicker and will try to get better info from the interlux guy. I'm also going to be using the bluewater brand of ablative rather than micron extra and wonder if you've noticed any problem of going away from the interlux product line for hot coating to 2000E?

scratchee 02-09-2013 12:13 PM

Re: Bottom paint flag coat theory vs. reality
 
Quote:

Originally Posted by Maine Sail (Post 987945)
That has not been my experience at all. A simple scuff in the spring gets it going again though I've done nothing and had it work perfectly. Are you buying "multi-season co-polymer ablatives? ...

The ONLY glitch we had was that I allowed the Pettit rep to talk me into Hydrocoat. HUGE, HUGE mistake. It failed to perform, failed to "ablade" and it all had to come off...

I've been mulling this over. I'm entering my second season as a boat owner, and last year I put on a coat of Hyrdocoat during my initial haul out, even though there seemed to be quite a bit of old buildup (the prior owner also used Hydrocoat.) This year, as last year, when I had it hauled and pressure washed, there were maybe a dozen or so areas that chipped away down to the barrier coat. These range in size from quarter to saucer-sized. I'm seriously contemplating just touching up these areas and the water line, instead of adding yet another coat.

One thing I will say is that I had no visible growth on the hull after several months in the water (upper Chesapeake.) So the paint seems to be doing its job in that respect. I just think there's way too much of it on the hull.

Sorry if this constitutes a thread-jack!

TQA 02-09-2013 01:07 PM

Re: Bottom paint flag coat theory vs. reality
 
Most A/F comes in different colors. Just change color with every application.

My previous job was done in red, current job is blue.

A hidden benefit of doing this is that when you apply the bottom paint you can see where the loss rate is highest and apply an extra coat.

chef2sail 02-09-2013 01:10 PM

Re: Bottom paint flag coat theory vs. reality
 
We actuallly do similar to what Maine does with the same paints. Our red base layer when it shows through lets us know when/ where the ablative is also wearing off. Like Maine we use Ultima 60 (blue) and are heading into our thrid season with it with great results. Used to use Micros Extra which also for the Chessie was a good paint.

Switched over to the Ultima because the ablation took place at a lower knot speed than the Micron. We did notice a difference as there was very little growth. We also have a diver gp down every two months or so.

Dave

tommays 02-10-2013 10:37 AM

Re: Bottom paint flag coat theory vs. reality
 
Please note that all of the below is from IMHP from owning boats over the last 35 years

My current boat Seafever is a good example because it had a fresh start 2 years ago with 100% current material

http://i565.photobucket.com/albums/s...1_06120011.jpg

I dont want to get into barrier coat other than i used it and the bottom paint was applied within the correct time window

http://i565.photobucket.com/albums/s...1_06190024.jpg

It started out with 5 quarts of Micron Extra which was about two light coats with a bit more on the waterline

http://i565.photobucket.com/albums/s...1_11200044.jpg

Season one ended up like this with the hauling yard giving it a powerwash and its exactly how it was relaunched

http://i565.photobucket.com/albums/s...ps9722c73a.jpg

http://i565.photobucket.com/albums/s...psf324e8c2.jpg

Season two ended up like this with the hauling yard giving it a powerwash and with a few hours of Scotch pads it will be ready for paint and another two year cycle

I consider this to be a perfect ending as none of the barrier coat was exposed until the yard power washed the boat and the least possible amount of paint was used


MY BOTTOM CARE METHOD :)

In my area of Long Island Sound barnacle larva are rampant and it sets the tone for your cleaning schedule as IF you let them get beyond larva your screwed :eek:

Season one nothing but a soft washcloth about every two weeks

Season TWO i find requires ONE session with a scrub brush to make the paint perform after sitting out of the water for 6 months

The rest of the season is the normal soft washcloth ;)

I sail and race with a large number of people who use everything sold and NOTHING withstands Northport any better

lancelot9898 02-10-2013 11:07 AM

Re: Bottom paint flag coat theory vs. reality
 
Would you mind saying what barrier coat was used and the time window that you used to get a chemical bond to the bottom paint? Good wax job!

tommays 02-10-2013 12:09 PM

Re: Bottom paint flag coat theory vs. reality
 
Yes with the barrier coat window i just hate seeing these things turn into a you did it wrong fest

Its a really good DIY Awlgrip job with NO wax but thank you :)


All times are GMT -4. The time now is 01:56 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012