http://www.supermarinepaint.com/bottom-r...M-1000.asp
Any opinions on this paint? I'm thinking about using it on my Super Skipjack. I like the wide range of colors it comes in and that you can apply it in low temperature.  I'm know some people have strong opinions on this but I'm not going to fiberglass.  I wasn't really planning to anyway but I just found out that I need to sell my current house and I need to get this project finished up before June, sooner if the house sells. My goal has always been to have wood hit water as soon as possible. I don't have a heated garage, so as soon as we get some warmer days I'm going to glue and screw like crazy. Meanwile I'll work on what I can. I want to get the inside of the bow, transom, and rudder box painted before I start closing things up. This paint sounds like it will give the hull some extra hardness.  I was wondering if piming is necessary with these paints? Also the directions still call for catalyzed auto body to fill the screw holes. But I thought I read somewhere that epoxy would be better if it's not getting fiberglassed over?Â
-Mark
Don't buy into the advertising hype of the web site's description of this paint. It's nothing fancy, just a modified alkyd (an oil based paint). The modifiers they're using are similar to all the other manufactures and offer nice self leveling and good drying properties. It's really an enamel, so it's at the low end of the scale for film toughness, durability and gloss retention. Considering over $100 per gallon, it better perform better then average alkyd's.
This paint will not add any noticeable "hardness" to wood surfaces. This paint will also not noticeably waterproof any surfaces it's on either. It's just an enamel, much like the stuff used on a porch or around the exterior windows of your house. Surface tension, in the latest generations of modified alkyds, have improved the "softness" of these types of paints, particularly compared to their "softer" brothers of previous generations, but it's still the softest of all the choices in paints, except for the cheapest of acrylics.
The use of auto body fillers on a wooden boat will quickly show why this hasn't been a commonly advised practice for several decades in the industry (I can't image why it's still recommended). In the 1960's some used these polyester fillers, but by the 1970's they were phased out in favor of epoxy based fillers (industry wide). There are lots of reasons for this, all are durability based. In short, it's just not very good, though it is cheap. Without the protection of epoxy overcoats, the polyester filler is going to swell up and fall off pretty quickly.
I'd probably tend to reach for a one-part polyurethane, if asked. They're so darn good and not really much more (even West Marine, not the least expensive source, shows around $110-117 for their gallon price) than the price you're quoting. The Brightside goes on nicely, smooths really well, and covers surprisingly well. I think you'd have a good amount left over with a gallon of that and a Weekender. If I recall correctly, I think it has taken around three quarts for our Weekenders, but I may be off on that.
Mike
If you are not going to 'glass the boat, polyurethanes are probably not the best paint you can use. They are good, hard and durable, but also not as forgiving with movement, which will undoubtedly occur with an un-glassed boat. You'd be much better off with a alkyd (oil) or acrylic (latex), which are more flexible.
Ooops, yeah, I was thinking about over-glass. I will say: we had a piece of unglassed plywood with LPU sitting out in the sun in SoCal for years and it looked amazingly good still when we tossed it. I think it had a layer of FeatherFill under it, no glass, and it did crack at the joint of the 2X6 to the plywood, but I was pretty surprised by how it had stood up.
Overall, it'd certainly be less risky to just do the job right, but this was a part for a show and it didn't need to stay more than a few weeks inside.
Mike
Thanks, for the Input. The plans say it's OK not to fiberglass, but the wisdom of experience on this board seems to speak otherwise. I'll probably go ahead and do it. I've dealt with fiberglass insulation a couple of times and it's nasty stuff. I guess with this though you are just sanding off the epoxy. The whole finishing process seem's like it could take as long as the build....
Finishing a Weekender by a skilled fairer will take about 20 hours. A novice will take 3 or 4 times that for the same level of finish. This assumes the butt joints and seams need special attention, there's a good bit of "waviness" to the assorted surfaces and most importantly, you want a "production boat" type finish (smooth, shinny with lots of gloss).
What a pro will do is go the length of the boat, in one, angled direction with a long boat and some 100 - 120 grit. Then back the other way at the opposite angle. This will "tell" the fairer where the hull is "hollow" (concave depression) or "proud" ((high spot). The areas that are just slightly hollow or proud will be quickly "knocked" down with the long board. Other wise the hollow spots are filled with fairing filler.
When dry, these are sanded down with the long board, then the whole hull given the same treatment as was done initially (same angle the full length of the hull then back at the opposite angle), which will reveal any low spots that were missed. These are filled and smoothed and you should be good to go for paint prep, but the novice will find they are stuck in the filling and fairing process much longer, just because they're learning as they go, make mistakes, don't know when it's "good enough", etc.
Interestingly enough, it's best to do this before the glass goes on, which is a big mistake beginners make. The smoother the base, the better the 'glass goes down and the less fairing you need over it. It's a lot easier to fair wood and filler then it is to fair epoxy coatings over 'glass and filler.
The next big mistake is to use the wrong tools. The DA (orbital) sander or palm sander will not fair a hull. It will smooth out very small areas, but can't fair. You need a long board. I have several of different shapes and sizes, plus air and electric powered, as well as the elbow grease models.
What is the difference between fair and smooth? A fair hull can be seen 50 feet away, though it may not be especially smooth. A smooth hull may not be fair and you really can't see the smoothness, but you can feel it. So this is the difference, your hand can feel a smooth hull, but you can see a fair one. Smooth is the immediate surface and how well it's been sanded. Fair affects much larger areas and it's how "sweet" the surfaces appear to "flow".
On an unfair hull, when you catch the light just right, you'll see humps and hollows in the finish. You can see these surface irregularities from a long way off. Picture a florescent light over the hood of your car. It reflects a long tube of light in the finish, following the curve of the hood. Now picture the same hood with a slight dent in it. The tube of light reflection will dip into the dent and the smooth strip of light will not be "fair" any more. This is the thing that sticks out like a sore thumb from a good distance (many yards). Surface smoothness is just how high a grit you used or if the surface is clean.
(02-24-2010, 03:41 AM)Paul Riccelli PE,NA link Wrote: [ -> ]Surface fairness is just how high a grit you used or if the surface is clean.
I think you mean "SMOOTHNESS is how high a grit you used", don´t you? You reiterated those two words until you confused everybody, including youself. But it was a good explanation about the difference of those two things that get mixed up so often
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You're right Timo, nice to see you were paying attention.
I retired to Tomales Bay some years back and for the fun of it I would go to the boatyard there and donate my time re-leveling waterlines for the fishermen. I also being a signman, would letter their boats. In the process I showed them about using "Industrial Enamel". Every paint store has it and can tint it any color you want. Back then boat paint was $75 gal and the stuff we were using was $22 gal. Also this stuff lasted twice as long. I still would give the outside a coat of epoxy if you are going to forgo the fiberglass. Some builders don't use primer but sand between 7 coats! Warren aks Zignman