Author Topic: Bottom Paint Technique  (Read 306 times)

Offline Anorada

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Bottom Paint Technique
« on: August 18, 2017, 12:38:16 PM »
I decided that our Sun Cat would stay in a nearby freshwater lake for most of the sailing season, with some trailering to other locales and some weekend excursions into saltwater. After getting a rather high quote, ($1K) from the local marina, I asked Com Pac how it did the job and received the following info: we start by cleaning the hull of wax and foreign matter with Interux 202 solvent.  We do not sand, cleaning is all we do.  Next we apply two coats of Interlux, Interprotect 2000E epoxy barrier coat.  After that we apply two coats of whatever antifouling paint the customer wants but our
standard paint is the paint depicted in the attached photo (a picture of West Marine Antifouling Bottom Paint).  This paint is an ablative and will probably work the best for you situation.

When I asked the marina if they could use the factory process, I got this reply: Remember not always “dealers” do things the correct way. I shiny smooth gelcoat is the perfect recipe for any product to peel. The reason of sanding is to remove the more wax possible from the gelcoat and make it less smooth. That way the Epoxy penetrate more into the gel coat. Is up to you if you don’t want to sand but even cleaning the whole is a process of lifting and time consuming. Difference will be probably two hours less of time.

Everyone has an opinion, so looking for this group's... I'd do it myself, but don't have a hoist, or rollers on the trailer, or even a place to perform the work... ( live in a golf villa)... suggestions?
« Last Edit: August 18, 2017, 01:21:37 PM by Anorada »

Offline Bilge Rat

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Re: Bottom Paint Technique
« Reply #1 on: August 18, 2017, 05:04:09 PM »
Do you need bottom paint if it's going to be in a freshwater lake for say the Summer season?
'09 Sun Cat, '06 Catalina 16.5, '00 Lido 14, '84 Holder 14

Offline brackish

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Re: Bottom Paint Technique
« Reply #2 on: August 18, 2017, 07:21:35 PM »
Yes, how long is the "sailing season" and how often do you pull out to go to salt?  If short do nothing, take it to a pressure wash facility where folks self wash their cars and pressure wash the bottom each time you pull.  You will be glad that you did not start down the slippery slope of barrier coat/anti-fouling bottom paint. 

If you are not in the water long enough to get a serious marine growth the new vinylester resins that I'm sure Compac uses now will certainly protect you from blisters for a season at a time. 

I stay in the water continuously, only pulling for maintenance.  I can assure you barrier coats fail and ablatives are only really good for a season without in water cleanings  Most of them don't like to be out of water off season, so you have to recoat.  I just finished spending a couple of weeks repairing my barrier coat and putting three coats of ablative (Blue Water Marine SCX Copper Shield 45 a Practical Sailor top performer and also best buy).  When I go back in it will be for three years with in water cleanings until the next haulout. 

It was a lot of work, jacking the boat up off the trailer to paint under rollers and bunks and crawling around the through the trailer.  If I had your situation assuming a short season in water I would not consider painting. 

BTW, my marina wanted about $1500 to do what I did, just sand and paint no epoxy barrier coat.   

Offline Anorada

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Re: Bottom Paint Technique
« Reply #3 on: August 18, 2017, 07:33:13 PM »
I probably should have added that I live in FL, and the only reason the boat isn't in the water all the time is that it's stinkin' hot.   Our best sailing is end of Sep thru May... since the water is very warm most of the time, the manufacturer recommends bottom painting if left in the water more than a month at a time.
« Last Edit: August 18, 2017, 07:37:37 PM by Anorada »

Offline brackish

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Re: Bottom Paint Technique
« Reply #4 on: August 19, 2017, 06:53:11 AM »
Well nine months at a time is too long to go unprotected, but a month is not.  I bought my 23 used, second owner, so it was already barrier coated and anti fouled when I got it.  I've been at  the same marina for seven years.  In retrospect, if I had an untouched bottom spending  the money for a lift instead of doing anything to the bottom would have been both cost effective and less of a hassle.

Offline Anorada

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Re: Bottom Paint Technique
« Reply #5 on: August 19, 2017, 07:27:22 PM »
Well, I think y'all have convinced me not to bottom paint, and just haul the boat out ever couple of weeks to wash it down and dry it out. Sounds like bottom paint is a constant battle, and one that I probably shouldn't start... maybe I'll just trade in my tohatsu 3.5 for a 4.0 with reverse instead -
 it will be cheaper. I think I'll just start another thread on how to reef the sail without a topping lift or lazy jacks... I need pictures or a diagram!

Offline Wes

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Re: Bottom Paint Technique
« Reply #6 on: August 20, 2017, 07:36:19 AM »
What is right or wrong depends entirely on water conditions and whether the boat will live in or out of water most of the time.

Here in NC, not unlike Florida, the water is warm most of the year and critters large and small (barnacles, mussels, algae, slime) grow fast and aggressively. For a boat that lives in the water, you must also be concerned with preventing blisters, not just keeping the critters away.

In my experience, the gold standard for a boat that will live in the water is:

1. Thorough hull clean/dewax with Interlux 202 or YM601. I prefer 601 because it's less toxic and provides some abrasion. This is an essential step regardless of age of boat, to remove traces of mold release wax from the manufacturing process.

2. Lightly sand gelcoat with 80 or 120 grit. Rare situation where I disagree with Hutchins folks.

3. Three heavy coats Interlux 2000e barrier coat.

4. Two or Three coats ablative bottom paint with the first coat applied while the last coat of 2000e is still uncured (tacky but not wet), for a good chemical bond. I like Interlux Micron CSC but there are many good products. Be dubious of cheap ones; the ingredients that keep critters away are expensive.

This is not a cheap process; the 2000e is $100/gal and the best antifouling paints are over $200/gal. But done as I have described, you are almost guaranteed a lifetime of protection from blisters and fouling. You will need to clean the bottom with hose and brush (easy) once a year or so (don't pressure wash ablative paints; you will just blast them off), and will need to repaint the bottom paint every 2-3 years (easy). This assumes climate and water like mine; situation may better in cold northern waters and worse in tropical ones.

One man's experience and opinion! Bring on the inevitable arguments...
"Bella", 1988 CP 19/3 #453
Washington, North Carolina

Offline brackish

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Re: Bottom Paint Technique
« Reply #7 on: August 20, 2017, 02:11:04 PM »
One man's experience and opinion! Bring on the inevitable arguments...

No argument from me on your process, seems sound and well thought out.  The OP has a Suncat.  With that size boat, I'd be looking for a marina with a mast up storage on trailer or invest in a lift.  I just got through with that three year, three coat ablative you talked about.  The memory of that job is still fresh in my mind, and any advice I've given is to avoid that altogether if possible.

Ironically my 12 year old boat has been in the water continuously and on this pull I had blisters on my ablative (no problem there) and blisters on my barrier coat (now that makes for a messy repair), but no blisters in the gelcoat/laminate itself.  I'm thinking the newer vinylesters are far superior to the older resins.  No telling how long that water was between the barrier coat and the gelcoat without any osmosis taking place.

Offline Tim Gardner

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Re: Bottom Paint Technique
« Reply #8 on: August 22, 2017, 03:01:53 PM »
FYI.  An article by Steve Smith of Smith and Company in Richmond CA.    A bit long but interesting info.  When I did by bottom repairs I followed his method to affect repairs to my 19.

TG
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Offline brackish

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Re: Bottom Paint Technique
« Reply #9 on: August 23, 2017, 09:31:06 PM »
FYI.  An article by Steve Smith of Smith and Company in Richmond CA.    A bit long but interesting info.  When I did by bottom repairs I followed his method to affect repairs to my 19.

TG

Interesting read Tim.  I think this is the same guy who sells Teak and Oak epoxy which is the only thing I'll use to do teak joinery.  Long cure by epoxy standards but no joint failures.  A chemistry that deals with the natural teak oils.