Polyurethane "oil" enamel for hull painting???

[Newb]

Ok, here's yet another question on painting the hull of a fiberglass boat. Please forgive me, but I've read and read the painting posts on here and couldn't find what I needed to know. I am considering repainting my 18' 1973 Starcraft American skiboat to change the incredibly ugly green hull to an all white or dark blue one. This boat will always be trailered and will be used in freshwater. Now, my question is this. I have read all the posts about using polyurethane on hulls and I was curious if a polyurethane "oil" enamel will work for this. This may be a dumb question and maybe all exterior polyurethanes are oil based (I'm not a painter or chemist), but this was the first time I had seen it labeled this way. The reason I ask is because I have access to a good deal on a couple of gallons and would really like to know if it will work. For what it's worth, it claims to be the toughest polyurethane on the market. My primary concerns are, will the paint stay on the boat and not peel or rub away during use, and can this be rolled or brushed on with decent results? For brushing or rolling, the can states that thinning is not necessary and it is self leveling. Also, does anyone know if this type of polyurethane needs to be wet sanded between coats and after the final coat to get a good shine to it or will sanding just dull the finish? This is just a pleasure boat for pulling skiers and tubes and occasionally doing a little fishing, so it doesn't have to look like a show boat, but the green has just got to go. One final question, is there any way to tell if the current green color is actually a gelcoat or paint without chipping or sanding a piece out of it to see what's underneath? As I say, these may be dumb questions, but I'm new to boat mechanics and the painting techniques are very different from my automotive background. I would greatly appreciate any and all opinions or ideas from the group. <br /><br />Thanks,<br />John

 

[Spidybot]

Re: Polyurethane "oil" enamel for hull painting???

Hi John,<br /><br />There are some good rules regarding paint jobs. Firtsly, the preparation means all. You can't possibly hide a bad pre job by painting it over. Therefore, it all starts with a thorough cleaning and repair of scratches & other cosmetic issues. Then sanding, maybe looking further into scratches and sanding again. Once ready, a good primer is needed to make the paint bond with the surface (a marine primer as is it also serves as a 'blocker' - you want to keep water away from the gelcoat!). Then the final paint, applied according to the instructions on the can. Paint should be applied so, that each layer levels. This also means to keep away from applied layers once the begin to level (look blank). Depending on the instructions, there may be certain intervals to respect between applying.<br /><br />If you're good at it, final polishing should not be needed. Remember, that any new gelcoat surface has less lustre than paint and a moulded hull will always look somewhat uneven once all shiny.<br /><br />This task is so big, you want be sure you get it right first time. Therefore marine paint & primer (preferably products known to work together) should be used. Choosing a paint just because of the price could spoil the whole project.<br /><br />Many boaters have such jobs made by car painters, as the job and procedure is very much the same. Those guys also have the right facilities to make the job.<br /><br />One of the firms in this industry has good info on their site: International Marine Coating <br /><br />None of the brands I can think of uses paint on the hull, unless for styling etc. The mentioned primer will stick to any surface so for that matter gelcoat and paint are as good.

 

[Bob_VT]

Re: Polyurethane "oil" enamel for hull painting???

Automotive Acrylic Urathane then covered by a clear coat of the same is very effective. You MUST prep the fiberglass clear of all waxes, oils and dirt prior to application.<br /><br />If you have a small run in the paint allow it to dry and wet sand the run out.<br /><br />Try www.autobodystore.com for paint tips. The guy Len who runs the site has painted allot of PWC hulls with good success.<br /><br />Bob

 

[ratherbefishin]

Re: Polyurethane "oil" enamel for hull painting???

The biggest reason for paint failure is adhesion problems caused by lack of adequite surface prparation- typically sanding and scraping.Chemical strippers are generally nasty stuff to work with, burn exposed skin, toxic fumes and can damage gel coats.They even take off 2 part epoxy paints.<br /> Check out the new water based strippers, they don't burn skin, no fumes, biodegradable, and don't damage gel coats.ICI markets them under the ''HydroStrip'' brand or check out the manufacturer www.napierenvironmental.com for a list of distributors.