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Bottom Paint and Anti-fouling Paint

Posted: Tue Sep 17, 2019 10:53 am
by Bayou Bum
Are “bottom paint” and “anti-fouling paint” the same paint?

Redoing a 13 classic and it has what looks to me to be topside paint on the bottom.

If it's not going to be in the water for more than a few days at a time, do I need to go back with true bottom paint
.

Or, can I use the AWLGRIP I plan to use for the topside?

Re: Do I even Need Bottom Paint ?

Posted: Tue Sep 17, 2019 1:02 pm
by biggiefl
You can use AWLGRIP but not for more than a week in the water i my opinion.

Re: Do I even Need Bottom Paint ?

Posted: Tue Sep 17, 2019 1:08 pm
by macfam
AWLGRIP is for above waterline only.

I’d use Pettit Hydrocoat water-based anti-fouling (Black, Blue, red, Green, or White) a couple of coats.

Taking in and out of water with Hydrocoat is fine. If you want to leave in the water longer, your protected.

One quart is all you need. Easy soap and water clean-up.

Re: Do I even Need Bottom Paint ?

Posted: Tue Sep 17, 2019 2:07 pm
by biggiefl
Macfam is correct but I have left mine in for up to a week with no problems. I don't think I would try longer. I know many who leave it in from Friday to Sunday or Monday with no problems. In Florida you really can't go more than a week or you will start barnacle growth which is so much fun to clean.

Re: Do I even Need Bottom Paint ?

Posted: Tue Sep 17, 2019 4:43 pm
by Bayou Bum
Was hoping to avoid using two different paints on the bottom. Maybe I will use a gloss anti-fouling paint.

Re: Bottom Paint and Anti-fouling Paint

Posted: Tue Sep 17, 2019 5:36 pm
by jimh
Read the advice on bottom paint from Boston Whaler.


http://continuouswave.com/whaler/refere ... tml#bottom

Re: Bottom Paint and Anti-fouling Paint

Posted: Wed Sep 18, 2019 8:16 am
by dtmackey
Awlgrip is not recommended nor designed for continuous water contact (immersion). Some people have no problems when leaving their boat in for relative short periods of time, days up to a week, but there are many variable that could impact the amount of time before paint failure occurs (water temp, salinity, etc...). Based on this you'd be better off with an immersion capable paint.

Imron, another polyurethane paint similar to Awlgrip is the same when it comes to using for boat bottoms.

I've seen Imron paint failure in situations where the paint was subjected to numerous immersion conditions, each not lasting over 48 hours, and the paint blistered within one season.

D-

Re: Bottom Paint and Anti-fouling Paint

Posted: Wed Sep 25, 2019 12:48 pm
by roundle1979
Earlier this summer I bought a fresh water 2004 Nantucket / Outrage 190 that had never been bottom painted. The below thread covers how I prepared mine to be kept in salt water 6 months out of the year:

viewtopic.php?f=4&t=4639

In summary:

—Mask off water line (after leaving boat in for 10 days to ensure 'scum line''
—Clean scum (amazing how quickly it appears)
—Sand gel coat below water line
—Apply two coats epoxy barrier coat
—Apply one coat hard coat (blue)
—Apply two coats ablative (black)

Paid $65 per foot. Guy who did it said that I should get 3 seasons before I'll need to re-apply ablative.

Re: Bottom Paint and Anti-fouling Paint

Posted: Wed Sep 25, 2019 1:59 pm
by dg22
I keep my 13-footer in the lake for 3 to 4 months of the year. I used Interlux products: InterProtect, a two-part epoxy coating to protect fiberglass hulls from water absorption; WaterTite, a marine filler; and VC17 bottom paint.

I first removed all the original bottom paint and gave it a good sand. I feathered out the blisters down to the fiberglass. I put on two coats of InterProtect and then used the WaterTite marine filler to fill any imperfections. The InterProtect is the primer for the WaterTite. I then sanded smooth and then applied two more coats of InterProtect. The coats over the WaterTite seals it. If you want a nice smooth surface, let the interprotect cure for a couple of days then use a 120 grit paper to sand smooth. I then applied two coats of VC17 bottom paint.

All the best with your project.

Re: Bottom Paint and Anti-fouling Paint

Posted: Wed Sep 25, 2019 6:29 pm
by Bayou Bum
Thanks for the guidance, lots of work involved no matter which way you go.

Have decided to go with new gel coat on the bottom. Folks at Totalboat have been very helpful.

Re: Bottom Paint and Anti-fouling Paint

Posted: Thu Sep 26, 2019 7:37 am
by jimh
dg22 wrote:I keep my 13-footer in the lake for 3 to 4 months of the year. I used Interlux products....


Thank you for the detailed account of your first hand experience in solving this problem. Your solution and your methods are very good advice for others to follow.

Re: Bottom Paint and Anti-fouling Paint

Posted: Thu Sep 26, 2019 2:20 pm
by rtk
I first removed all the original bottom paint and gave it a good sand. I feathered out the blisters down to the fiberglass. I put on two coats of InterProtect and then used the WaterTite marine filler to fill any imperfections. The InterProtect is the primer for the WaterTite. I then sanded smooth and then applied two more coats of InterProtect. The coats over the WaterTite seals it. If you want a nice smooth surface, let the interprotect cure for a couple of days then use a 120 grit paper to sand smooth. I then applied two coats of VC17 bottom paint.


You did a textbook perfect job dg22. I used to work at a marina in the late 1980's and we did a lot of osmotic blister repair/prevention work. We also did some racing bottoms for sailboats using hard finish bottom paints and burnishing techniques.

https://interlux.com/en/us/boat-paint/p ... tect-2000e

The Interlux Interprotect 2000E is an exceptional product. I don't know if was called that 30 years ago but it was a similar Interlux product we utilized. Applying the primer to the substrate in need of filling/repair prior to doing the repair is an important step in the process.

https://interlux.com/en/us/boat-paint/a ... ith-biolux

https://international-yachtpaint.com/s3 ... 1551226921

I like your paint choice a lot for a hard finish but I am going to go with this bottom paint:

https://interlux.com/en/us/boat-paint/a ... ing-bronze

I like the bronze color for an old boat.

Nice work!

Rich

Re: Bottom Paint and Anti-fouling Paint

Posted: Fri Sep 27, 2019 9:38 am
by dg22
Thank-you. The folks at the Rigging Shoppe in Scarborough Ontario where I buy my boat paint helped me with a step by step plan. I was really happy with the results.