Polyurethane paint vs. Enamel

[garbler]

That is why you Alexseal, just roll and no tipping required if you use the correct additive.

But same old serious chemical threat a coating systems using isocyanates.

 

[sean9c]

I've a friend who is a boat painter, his dad was a boat painter. I often joke with him that his dad was brushing enamels and varnishes that are pretty safe now he is spraying rat poison.

But same old serious chemical threat a coating systems using isocyanates.

 

[Xlantic]

Internationals' Perfection Pro (not to be confused with Perfection Plus) is a two-part polyurethane that can be rolled on with no need to tip.

Pricey but rolled results cannot be distinguished from spayed ones.

Not sure it is available in the US.

 

[garbler]

HeadedtoTexas: I’m a big fan of a GOOD gelcoat job. If cared for properly I’ve seen 45 year old production boats with polyester gelcoat that can be compounded, buffed and waxed that look great. But when graphics and involved angular topside striping became popular it became impossible costwise for builders to pull this off working inside the mold. The more cost effective solution was using LP coatings. These builders stole a page from the airplane and big truck builders and it’s the standard today.

I recall surveying a tired looking 1978 Bristol 40 Yawl back in the 80’s at Kettenburg’s yard in San Diego. Her topside were such a mess she scared off most buyers and those who did show interest lowballed the owner to death. I told him to find a gelcoat man to do some patching and a crew to compound and buff out the hull. Apparently the hull came back to life beautifully and the boat sold in two weeks. You’ll never see Awlgrip jobs this old that could still be restored not in places like San Diego or where the sun works long hours

Rick

 

[Comodave]

But same old serious chemical threat a coating systems using isocyanates.

Rolling outside and using a respirator and you shouldn’t have any problems.

 

[sean9c]

Nothing beats gelcoat. If I was looking for a boat one of my considerations would be that the it's gelcoated rather than painted and that the gelcoat is still good

HeadedtoTexas: I’m a big fan of a GOOD gelcoat job. If cared for properly I’ve seen 45 year old production boats with polyester gelcoat that can be compounded, buffed and waxed that look great. But when graphics and involved angular topside striping became popular it became impossible costwise for builders to pull this off working inside the mold. The more cost effective solution was using LP coatings. These builders stole a page from the airplane and big truck builders and it’s the standard today.

I recall surveying a tired looking 1978 Bristol 40 Yawl back in the 80’s at Kettenburg’s yard in San Diego. Her topside were such a mess she scared off most buyers and those who did show interest lowballed the owner to death. I told him to find a gelcoat man to do some patching and a crew to compound and buff out the hull. Apparently the hull came back to life beautifully and the boat sold in two weeks. You’ll never see Awlgrip jobs this old that could still be restored not in places like San Diego or where the sun works long hours

Rick

 

[sean9c]

I've tried this roll only routine with Perfection and others, it works fine. But only if you're doing panels with no corners or areas where you can't get a roller in. Great for hulls, lousy for decks and cabins. The problem is that proponents of roll only under thin the paint, it rolls fine but you can't brush it. So you get to a corner or something where you have to brush and blend it in and it's not working so good.
I've found that unless you're just doing a hull plan to roll and tip and thin your paint accordingly.
The other thing that doesn't get talked about much is roller covers. IMO rolling and tipping works best with foam roller covers. Foam roller covers don't like LP and break down quickly. Unless you're doing something small make sure that you have a bunch on hand.

Internationals' Perfection Pro (not to be confused with Perfection Plus) is a two-part polyurethane that can be rolled on with no need to tip.

Pricey but rolled results cannot be distinguished from spayed ones.

Not sure it is available in the US.

 

[mvweebles]

Nothing beats gelcoat. If I was looking for a boat one of my considerations would be that the it's gelcoated rather than painted and that the gelcoat is still good

I had the option to re-gelcoat my boat instead of painting it. After some research including a decent thread here on TF which Steve D'antonio was kind enough to contribute, decision to paint was easy. Now, part of that is that gelcoat is made to be applied into a mold, but still, it's much more porous than paint. Waxing will definitely help prolong life of gelcoat, but in a boat, waxing and compounding is tedious work.

Would also note that there are a couple brands that paint their boats when new including Hatteras.

Peter

 

[Comodave]

I've tried this roll only routine with Perfection and others, it works fine. But only if you're doing panels with no corners or areas where you can't get a roller in. Great for hulls, lousy for decks and cabins. The problem is that proponents of roll only under thin the paint, it rolls fine but you can't brush it. So you get to a corner or something where you have to brush and blend it in and it's not working so good.
I've found that unless you're just doing a hull plan to roll and tip and thin your paint accordingly.
The other thing that doesn't get talked about much is roller covers. IMO rolling and tipping works best with foam roller covers. Foam roller covers don't like LP and break down quickly. Unless you're doing something small make sure that you have a bunch on hand.

Andy at BoatWorks Today has some rollers he recommends for rolling out LP paint. You might look and see what he is using.

 

[garbler]

Gelcoat is applied first into a mold because that is the easiest most cost effective method of application. But gelcoat is certainly not limited to mold application. Gelcoat is routinely sprayed and when properly conditioned and handled by a competent applicator can apply numerous coats per day since air drying is not needed.

As I noted above lots of production builders have changed over to using LP ( Awlgrip, Interlux, Imron, Alexseal etc. ) topside coatings in favor of gelcoat mostly to offer graphic stripes, two tone and wider range of colors. Since they are in business to make a profit it should not really surprise anybody that a smart builder will capitalize on telling buyers they get a new Awlgrip job of their flavor on their new boat. Of course this is a sales feature that does not come free and like any paint shop will tell you opens up lots of avenues for those ‘ minor ‘ additional charges. Some colors are more money like ‘Flag Blue ‘ or those lustrous dark shiney colors that show every flaw in the hull. ‘ Sorry folks but we can’t offer that color at this time or that will cost XX dollars more ‘ . However spraying these highly toxic coatings cost serious money for a yard. Depending on the state and the EPA regulations handling and spraying these products can require lots of special equipment from exotic filtration including waterfall filters with drainage floors and specially designed catch basins. Because most yards are on the waterfront and prime suspects for toxic run off you can bet the laws are stringent, violations costly and random inspections constant. So nothing is free and lots of yards therefore won’t handle this stuff

Good gelcoat is not completely 100% moisture proof but then hull topsides aren’t submerged and if hydrolysis is your fear just try to run the numbers of how many older GRP production boats have suffered serious blistering. Fact is the problem hit the news, scared the crap out of owners, builders and resin manufacturers. Smart yards jumped on it and immediately understood hull stripping, drying and coating with epoxy was not only the answer but a new business that became profitable enough to build dedicated environmentally controlled shops, gelcoat strippers and crews trained in this treatment. After a while this business has begun to dry up ( pun maybe intended ) but for years lots of yards had the Univ Rhode Island’s reports and other documents on hand. I’ve seen my share of Valiant cutters ( Uniflite ) and three Swans that were totaled from this condition but it was very rare. Honestly I’m in the corner that doesn’t believe it’s as simple as minor porosity in a polyester/glass fiber matrix skinned with polyester gelcoat with minor permeability. And tell me why don’t the Taiwanese hulls have this problem. All the years and all the Taiwanese hulls I’ve crawled under and around and I have personally never encountered gelcoat blistering on a single one ? The resin manufacturers remained silent back then but today the problem seems to have mitigated.

Rick

 

[mvweebles]

Here is the thread I mentioned. Specifically #16, 18, and 42. D'antonio specifically mentions issue with dark gelcoat in #42. And addresses why gelcoat is not a good re-paint candidate in 18 (might be 16).

https://www.trawlerforum.com/forums/showthread.php?t=48035

Rightly or wrongly, it's the thread I relied upon in deciding on paint, and landed on Alexseal. Frankly, I've never gone wrong listening to guidance from Steve D'antonio (and a few others, including Comodave who also chimed in).

All I can say is it's how I made my decision. I did not believe Gelcoat was a viable option compared to paint

Peter.

 

[sean9c]

Ya, re-gelcoating doesn't work. It's not nearly as durable. That's why Ocean Alexanders end up looking so funky so fast. They apply gelcoat in the mold but then cut, patch and generally screw it up. They then re-gelcoat the boat before it ships

I had the option to re-gelcoat my boat instead of painting it. After some research including a decent thread here on TF which Steve D'antonio was kind enough to contribute, decision to paint was easy. Now, part of that is that gelcoat is made to be applied into a mold, but still, it's much more porous than paint. Waxing will definitely help prolong life of gelcoat, but in a boat, waxing and compounding is tedious work.

Would also note that there are a couple brands that paint their boats when new including Hatteras.

Peter

 

[rslifkin]

I've seen re-done gelcoat jobs last well (in a couple of cases I didn't know it was sprayed gelcoat until someone told me, I assumed it was either original or a good paint job), but there's a reason very few people do it. Re-gelcoating something, getting it to look good, and having it last is much harder than painting something well. So few people are actually good at it, and few people feel it's worth the time and effort to do.

 

[DDW]

Gelcoat also seems to harden differently in air vs in the mold. In the mold air is excluded from the surface during cure. It seems to be harder, less porous, and longer lasting from the mold.

 

[rslifkin]

Gelcoat also seems to harden differently in air vs in the mold. In the mold air is excluded from the surface during cure. It seems to be harder, less porous, and longer lasting from the mold.

Thinking about it, when I've seen gelcoat sprayed, they typically apply plastic over the area while it's curing vs just using a waxed gelcoat and letting it cure in the open air. I'd always wondered why, but I'm betting that's the reason.

 

[garbler]

I can tell you there are so+called painters, so-called carpenters and so-called mechanics. Level of skill is all over the place but the really good ones you have to wait for and pay more. Same with materials from paint, wood to engine parts so saying gelcoat is no good just ain’t true. What is a fact is that, as rslifkin points out, there are fewer and fewer guys who can shoot, compound and buff gelcoat to a high quality finish. You have to have the proper gun set up with with the right air mix, pressure and tip and not lay down too much material as gelcoat cracks when it’s too thick. Just notice cracks in your glass cockpit and around hatch coamings where there is an inside radius. The gel pools, kicks off too thick and becomes brittle.

But gelcoat applicators are out there and I’ve worked with several from Florida to MA and California. BTW GOOD gelcoat touch up masters are getting harder to find also. The hacks leave a job with color shift and a halo six months later. Polyester, vinylester or epoxy are thermosetting resins that don’t need air to set. Gelcoat is laid down first in the mold so forms on a very slick waxed perfect surface on the face and gets pushed down by the laminating crew’s rollers. Optimal conditions. It does have a tendency to run but compounding with fine abrasives takes care of that. Simulated plank seams on a glass hull looks traditional but fact is it hides all kinds of problems in the mold.

Rick

 

[mvweebles]

I can tell you there are so+called painters, so-called carpenters and so-called mechanics. Level of skill is all over the place but the really good ones you have to wait for and pay more. Same with materials from paint, wood to engine parts so saying gelcoat is no good just ain’t true. What is a fact is that, as rslifkin points out, there are fewer and fewer guys who can shoot, compound and buff gelcoat to a high quality finish. You have to have the proper gun set up with with the right air mix, pressure and tip and not lay down too much material as gelcoat cracks when it’s too thick. Just notice cracks in your glass cockpit and around hatch coamings where there is an inside radius. The gel pools, kicks off too thick and becomes brittle.

But gelcoat applicators are out there and I’ve worked with several from Florida to MA and California. BTW GOOD gelcoat touch up masters are getting harder to find also. The hacks leave a job with color shift and a halo six months later. Polyester, vinylester or epoxy are thermosetting resins that don’t need air to set. Gelcoat is laid down first in the mold so forms on a very slick waxed perfect surface on the face and gets pushed down by the laminating crew’s rollers. Optimal conditions. It does have a tendency to run but compounding with fine abrasives takes care of that. Simulated plank seams on a glass hull looks traditional but fact is it hides all kinds of problems in the mold.

Rick

I didn't know it was that specailized. The guys in Ensenada do gelcoat repairs all the time. Colored hulls are impossible, but they seem to do a fine job with something within rifle shot of white. I have to say that what looks difficult to my eyes seems to be simple to them. I guess that's why they get paid the big-bucks (chargeable rate is $17/hr).

Peter

 

[rslifkin]

I didn't know it was that specailized. The guys in Ensenada do gelcoat repairs all the time. Colored hulls are impossible, but they seem to do a fine job with something within rifle shot of white. I have to say that what looks difficult to my eyes seems to be simple to them. I guess that's why they get paid the big-bucks (chargeable rate is $17/hr).

Peter

The really good guys can even manage to match a darker colored hull. Of course, as with any dark color, it'll only stay looking good (and matching the surroundings) as long as it's kept waxed, etc.

 

[DDW]

You can match aged gelcoat. But it won't stay matched. Give it a year or two and you'll see it. Not really a negative compared to Awlgrip (or the other polyester polyurethanes), which is also impossible to repair invisibly (long term). That is a plus for the acrylic polyurethanes, it is possible to do a pretty good repair that you won't see a year or two later.

 

[rslifkin]

You can match aged gelcoat. But it won't stay matched. Give it a year or two and you'll see it. Not really a negative compared to Awlgrip (or the other polyester polyurethanes), which is also impossible to repair invisibly (long term). That is a plus for the acrylic polyurethanes, it is possible to do a pretty good repair that you won't see a year or two later.

Agreed, getting things to fade the same is a challenge. I'd expect with something like gelcoat with plenty of thickness remaining, because the pigment is all the way through, you've got a chance though. You'd have to compound the heck out of the old gelcoat to try to remove some of the fading and hopefully get it back to a less faded state, that way it would fade more similarly to the new stuff. I'd still expect you won't get it perfect though.



There are definitely some old, small repairs on my boat that don't quite match anymore, but I don't remember seeing them years ago (before it was my boat) even though I know the repairs are older than my experience with this boat.

 

[DDW]

Even gelcoat repairs done at the time of manufacture will show up over time. On my boat they add the transom out of the mold, re-gelcoat the joint. There are also a couple of small repairs done after molding and before delivery. With a lot of compounding and wax and bright sun, hard to see, but they always come back. The gelcoat shot in the air has different characteristics, even though it was the same product used at the same time as the rest done in a closed mold. A lot harder to see on a white boat, mine is flag blue.

 

[jcurry]

Looking at "topside paints". Mostly at the marine stores I see the polyurethane paints and primers, but find other brands such as Rustoleum marine coatings are an enamel.

Anyone have experience with both? I like to save some money when I can but also only want to do the job once or a least not have to redo it right away.

I have a boat not a yacht.

Hoping to not have to 'tip' in the process.

First painting projects will be the wood mast/boom and the flybridge 'brow'.

Thanks

My wife and I painted our 1986 Mainship 34 from the bridge to the rail, including the decks, cabin and cockpit with Awlgrip. We used the small diameter "hot dog" rollers and tipped with a brush. There is definitely a learning curve on vertical surfaces which is why we used the small diameter rollers; it's too easy to get too much paint on with a standard roller. Practice on verticals before trying to paint your boat. The standard size rollers were fine on the cabin tops and decks. A fellow Mainship owner could not believe that the cabin sides were not sprayed. I have brushed Brightside on small boats with excellent results, brush marks level out perfectly and the paint holds up well, just not as well as two part polyurethanes.

 

[Simi 60]

I'll be happy this year to get paint on the cabin sides , not overly fussed on finish as long as she's got uniform colour and got protection from the elements.

To much of it for me to get too anal about and life's too short to turn her into an art installation

After a good scrub I'll be giving the sides a once over with thickened epoxy hi build to fill any paint cracks
When that's kicked it'll get knocked back with machine sanded 80 grit and probably have a good quality self priming exterior acrylic/latex rolled on.
Advantage is water clean up and dries fast.
2 coats in one day.

The roof, Portugese bridge front and rails got that treatment 6+ years ago and it's held up ok and looks a hell of a lot better than it did when we got her.
I re coated some rail 12 mths ago, scrubbed it, let it dry and rolled on paint and it looked fine, even better from 20ft away

 

[Comodave]

Yes, indeed you can get amazing results with DIY painting. We have painted several complete boats, a 30’ and a 41’. Most of the work is in the prep. If I were to do another one I would use Alexseal paint with the tipping additive in it so you only need to roll it.

 

[Mako]

After a good scrub I'll be giving the sides a once over with thickened epoxy hi build to fill any paint cracks
When that's kicked it'll get knocked back with machine sanded 80 grit and probably have a good quality self priming exterior acrylic/latex rolled on.

On a previous boat of mine, the wood deckhouse had canvas over the roof, then painted with enamel. I always thought that some sort of waterproof coating would have been an improvement. However, after 40+ years it was still watertight and had no rot anywhere. Plus it cost about $10 to paint it once a year and kept it looking great from 20 feet away.

Maybe those old timers knew what they were doing, compared to us young whippersnappers!

 

[PM]

Rick, I love your rules of thumb.You missed one. "Prep is everything"

pete

 

[Labrador Coaster]

Very true and that little jewel probably says more than all of my ramblings



Thanks

Not at all, your advice is spot on, prepping is important sure, but so is the rest, especially with two part, temp, weather etc..