Using 1 part poly paint.

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May 18, 2012
12
macgregor/venture 1974 25 fortuna
Because I have a trailer boat. What's the problem I would get myself into if I used a 1 part poly paint,AKA topside paint, all around? I don't need antifouling on the bottom.
 
Aug 7, 2011
496
MacGregor 26S Lakeland, FL
I'm interested to hear the feedback you get, because I'm close to having to do remedial painting on my hull, and don't want to invest a ton in it at the moment...at least not until I get to see how much we like it.
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
I've read reports on some of the other boards from people who have used 1 part and 2 part and most say that if they did it again they would stick with 2 part.

I know that 2 part car paints are much more durable than 1 part and look better years longer. It might be more expensive, but considering the labor that goes into a good paint job I'd only want to do it once if at all possible,

Sum

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Sep 30, 2008
68
Macgregor venture 25 port dufferin
I painted my top side non skid areas of my 1975 venture with pettit 1 part epoxy, using a foam brush, did all the required prep and it turned out great. A maroon color.( sorry no before and after pics) Did it in the spring and it has held up well all summer, the only problem in doing it is that it made the rest of the top side look bad, guess what Im doing in the spring next year?
 
Jan 19, 2010
12,754
Hobie 16 & Rhodes 22 Skeeter Charleston
One part paint is usually urethane and two part is usually epoxy but that is not a 100% rule. There are plenty of good quality urethane paints on the market but they are not a lot cheaper than an epoxy. A caution with epoxy, unless the epoxy has an added UV protection agent, it will chalk when exposed to UV light.
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
One part paint is usually urethane and two part is usually epoxy but that is not a 100% rule. There are plenty of good quality urethane paints on the market but they are not a lot cheaper than an epoxy. A caution with epoxy, unless the epoxy has an added UV protection agent, it will chalk when exposed to UV light.
Most of the urethanes that I've been familiar with in auto paints are a 2 part in that you mix an activator with the urethane and usually a reducer that is formulated for the temps that you are painting at.

There are 'single stage' urethane and they also need to be mixed with an activator, but dry glossy which is why they are called single stage (they are still a 2 part paint).

Then there are 'two stage' urethanes and they also mix with an activator but go on dull. You use a clear coat urethane over those thus since you paint in two steps they are called 'two stage' and are also a 2 part paint.

Then if you get into metallics and pearls and other fancy stuff you can have even more stages.

I think some confusion comes with the terms "2 part" and
"2 stage". It the paint mixes with an activator/hardener it is 2 part (the reducer doesn't count).

Like you said most of the automotive epoxy primers I'm aware of are really good, but you don't want to leave the car exposed to the sun with them for extended periods for the reason you mentioned. Also you usually have to top coat those with other primers or paint within at least 1 week to get a good chemical bond between them and any subsequent coats of paint. If you get past the week you sand them and re-coat with more epoxy primer.

The above is true for automotive paints and there are so many different paints out there now, both auto and boat that before you start or buy you need to read the instruction sheets to make sure you understand the whole process. Done right and in the time tables specified you can get some really durable paints.

Also a warning. About any 2 part paint that requires an activator can be extremely dangerous to your health. If I'm painting these with a guy I use a supplied air mask that supplies me with air from outside the space I'm spraying in. You at least need a good charcoal filter and even those aren't really recommended any more. If you use one and smell paint it is time to replace the cartridge and once exposed to air the cartridge starts to go down hill. Painting a boat outside with one is probably going to be ok, but don't just use a dust mast. If the primers you use mix with an activator/hardner the same applies even though they are a primer.

Sum

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Fred

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Sep 27, 2008
517
Catalina 28 mkii 745 Ottawa, Ontario, CA
I have painted my boat above and including the waterline strip using Petit (one part) urethane. It stands up very well however the waterline strip, which tends to get wet by splash even when moored, does tend to blister. I would not advise to use this paint below the waterline unless you expect never to have the boat in the water for more than a few days at a time. remember though that the next potential buyer may consider it a deal breaker if the whole bottom side needs to be stripped of the urethane paint.
 
Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
Here in Canada (Ontario specifically) we have new environmental rules about paint. Back on September 9/2012 the paint/all stores had to stop selling Alkyd/Enamel paint and primers. There is one exception I have noticed Rustoleum/Tremclad on shelves and asked why. I'm told it's on it's way out "but" there isn't a suitable replacement for rust paint...Yet.
Even back last December of 2011 I couldn't get a urethane paint for my truck. It had to be Latex. At least from the supplier I was using. They had already made the stock switch. They said it wasn't just environmental laws but health and safety laws stopping the use.
I'm not sure what the marine paint situation is here yet. I have one Q of Interlux topside waiting since spring to do my bilge areas as soon as I can stop the leaks from the top. Also I'm planning to strip and re-paint the exterior of the boat to remove a bad paint job before next sailing season.
Here is a link to the Westmarine paint site. http://www.westmarine.com/webapp/wc...nt+&+Solvents&viewTaskName=SiteSearchView
It looks like it all classified as not shippable outside the US?? Hmm.
 
Jan 19, 2010
12,754
Hobie 16 & Rhodes 22 Skeeter Charleston
I think some confusion comes with the terms "2 part" and
"2 stage". It the paint mixes with an activator/hardener it is 2 part (the reducer doesn't count).
Whew! That is a bit more hard corp that I want to be. I don't think I'd want to try spraying. The polyurethanes I've used came from this place...

http://supermarinepaint.com/?gclid=CM6xgYGA8rICFZSd4Aod_3YARA

The stuff was one part single application (just like regular paint) and it had excellent self leveling properties. Took about a week to get fully "cured". After a day it felt dry but if you walked around out it, you would leave heal marks (ask how I know).

This is the paint I used on my MacGregor. I can also say it had excellent coverage. I purchased two gallons, one for the hull sides and one color for the top sides. I had more than half of each gallon left over.... which as been nice when I bang up my paint job on the pier... :eek:

... and the bottom is just Rustoleum (good stuff too).
 

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