Hull painting woes

[powrguy]

Well, I did all the tedious sanding, cleaning, sanding, wipedowns, etc., then applied the primer (white primer for urethane Megagloss Marine Paint), which is a polyurethane 1 part paint. Had seen good reviews on it, and bought a gallon. After two coats of the primer (sanded with 220 grit between coats, and after last coat), I tried rollering the paint on with a foam roller.

Needless to say, the result was roller marks galore with the first coat. So, thinking the paint should be thinner, I added about 5%-10% to the next coat, but first, I again sanded lightly to remove the roller marks and then tried the thinned paint. MORE roller marks with that coat, too.

Finally, I REALLY got tired of the rollermarks, so I sanded all the rollermarks out, then tried painting with a real high quality bristled brush. I also tried MORE thinner, which was hi-flash naptha that was the recommended thinner on the can of paint, and now I got brush marks and some sags/curtains.

Am I putting the paint on too thick? Am I not thinning the paint enough to get it to flow out?

The conditions are:

In the shade
Temp's in the 65-70 degree range
Humidity is around 55-65%

I am really gettin' tired of re-sanding the rollermarks/brushmarks over and over, and just can't seem to get the paint to flow out. No problem with the paint drying or holding properly, as it dries to the touch in 4 hours, and can be sanded next day.

Any suggestions appreciated.

(I ordered another gallon yesterday, as I am down to about a quart left, and I thought maybe I should try it un-thinned?)

thanks

 

[Bob_VT]

Re: Hull painting woes

Roll and tip

I think you need to read up on it and even you tube has videos for it............

The foam roller ..... are you using high density? The brush used in conjunction needs to be very high quality too.

 

[redfury]

Re: Hull painting woes

If you are leaving roller marks, then you are putting the paint on too thin. How much Naptha are you using? If you are rolling the paint, you shouldn't need any thinner at all....10% at most. The more thinner you use, the worse the paint will look and act. It defeats the self leveling properties built into the chemical make up of the paint, not to mention kills the glossiness of the paint.

If you are having a hard time with the paint flowing and self leveling and think it is too thick, then you may want to look at Penetrol as an additive. It will make the paint flow easier without thinning it. Penetrol can also be used as a conditioner for Fiberglass.

 

[Free Bird]

Re: Hull painting woes

Mega Gloss should behave like Petit Easypoxy or Interlux Brightside so you might study any videos for those paints. I have not used them but I did get a finish that looks sprayed with Awlgrip. I think it sounds like your paint is too thick. It should be the consistency of milk. You roll very very lightly. You DO NOT get much coverage with each coat. When applying it my roller did not touch the boat, only the paint. Does that make any sense? By three thin coats it'll look great. When I painted it was 70 degrees and I used 25 percent reducer (thinner). I used the white foam "cabinet" rollers from Home Depot. Changed roller three times painting outside of a 14'. They break down. I tipped with a foam paint brush. They break down faster. I didn't tip with it so much as I used it to brush away any drips. I don't know about using penetral. You should use what the manufacturer recommends. I guess you already know to sand down the curtains and imperfections before you begin again. All this aggravation is why the pros want 7k to paint a runabout. Keep us updated about your paint project as there does not seem to be much on the net on Mega Gloss. From the packaging I suspect that Mega Gloss makes West Marine's house brand . Naturally it costs more than Mega Gloss.

 

[powrguy]

Re: Hull painting woes

Well, your post indicates the paint might be too thick, if you say it should be like "milk". The post above yours indicates the paint is too thin! That's part of my dilemna; I am not sure how much to thin the paint. I am going to use mineral spirits as thinner on the next coat, as opposed to the naptha I previously used. Maybe it's flashing TOO FAST, and not allowing flow-out?

As far as adding Penetrol; I read that it's not for use in urethanes, but rather in Alkyd enamels. I don't want to add Pentrol, then.

I may try again with a roller, without thinning, and see how that goes. I have a pure china bristle very high quality brush to tip with, too. I really thought I was probably putting too much pressure on the roller, to spread the paint out. Maybe I need to just sort of lay the paint on, and not over-roll too much. I will try to do light coats, and tip only if necessary? Is rolling over and over, back and forth to even the coat, wrong? Should I roll in one direction only? I know they talk of leaving a wet edge to lap the paint, but it's hard to lap as it seems the paint sets up real quick, and the lap marks then tend to show. This is why I thought that thinning would help the paint flow, but maybe the thinning with the high flash naptha is causing the paint to set too quickly? I just don't know if the "sagging" or "curtains" problem is caused by the paint being too thick, or too thin.


thanks for the input

 

[redfury]

Re: Hull painting woes

Yup, you are right about the naptha and your lines...naptha is a fast drying solvent. You can use different solvents for different purposes. I don't know the site off hand, but you can read up on the general purposes and actions of different solvents.

We used Naptha for a while in our poly for hardwood floors and had similar problems as you describe in your last post and switched to paint thinner. Of course, I rarely use it...mostly as a brush cleaner if that.

Actually, now that I think of it, I think someone here posted about the different solvents you can use in your paint...

 

[lowkee]

Re: Hull painting woes

I feel your pain. Where I left off my boat was at the same issue you are having. I roll and tipped EasyPoxy and it sagged all over the place. I'm sure I put it on much too thick. Next time (when that time comes) I'll be sure to much thinner coats and much slower flashing thinner. I keep reading if you can't see through your coat of paint, it's much too thick. Full coverage should REQUIRE 2+ coats to ensure a smooth and proper application. It'll even say that on the can, though we have a tendency to want to only paint once and slather it on anyway. Hope that helps, but don't take it as gospel, as I have yet to finish my boat, for the exact reason my paint hates me, too!

 

[drewpster]

Re: Hull painting woes

One thing I have certainly learned about one part poly paints is that they hate wind. Even a slight breeze will cause them to flash. I have had the best luck painting early in the morning just after the dew burns off. The wind is calmest and the humidity eases up. I have painted outside in 85 deg weather as long as the wind is calm, it flows out smooth without any thinner at all.

 

[redfury]

Re: Hull painting woes

Not to mention early in the morning, the bug activity is less than in the evening! Seems that dew point and barometric pressure have a hand in how well paint goes down, as there are some days where nothing goes right for me, and others, everything is perfect...and I'm using the exact same product in the exact same homes/areas of our work area.

 

[powrguy]

Re: Hull painting woes

Well, I feel better now, knowing others have gone through the same frustration. I think the mineral spirits will make a lot of difference, as the naptha they talked me into, I think, caused the paint to set way too fast, and never getting the time to flow out properly. I have another gallon of the MegaGloss Polyurethane on the way, so this week I will be trying AGAIN.

Thanks for all the input.