Comments about System Three System Three - WR-LPU Linear Polyurethane Topcoat - Water-borne:

I agree with both reviewers, this stuff is nice in some ways, very frustrating in others. To be charitable, let's say it has a big learning curve.

I was interested in using it to paint my 20' glass sailboat. I had previously used Interlux 2-part urethane, rolled and tipped, almost 30 years ago. That stuff was very difficult, but in the end gave a nice finish that help up extraordinarily well with a buff-out every spring with rubbing compound. I wanted something without all the toxicity and expensive solvents, so I gave the System-3 stuff on a plywood skiff I just built.

I painted over plywood that had received 2 coats of epoxy resin only coating. I used a 4" foam roller (Shur-line) and a 4" foam brush to tip. I thinned with 15%. I only had a quart, the info said 400 sqft/gal, I figured I had ~40 sqft, so with thinning, I was shooting for 3 coats/batches.

The first couple of coats went on well. I applied it thinly, fearing sags/runs, but the stuff set up so fast that wasn't much of a risk. I started running into trouble on the third coat, and the fourth was a disaster (I was getting about twice the coverage I planned, so maybe the application was too thin).

The problem was that the paint was setting up so fast that even working in very small sections and rolling very fast, I couldn't keep a wet edge. I would up with a blotchy mess.

I was painting in probably worst-case conditions. The temp had climbed to near 90, and the humidity wasn't all that high. Things got worse very quickly with temperature increase.

The next morning, I got up at dawn (68 degrees) and wet sanded the day before's mess with 220. I then mixed up a last batch and started again. Things went much more smoothly. I had no trouble keeping a wet edge and feathering one section into another. The coat looked pretty even, despite drying very fast.

Bottom line, this stuff is very sensitive to heat & humidity. You want cool temps and high humidity. By the end of my first day 2 coat, the temp had gone over 80, and I decided to not attempt another coat, despite having enough paint for one. I tried a thick coat just on the transom, and it set before the tip marks had leveled completely. I decided not to push my luck.

The good news is that the stuff has no odor or exotic solvents. I found wet sanding that it is very hard, even after only an overnight cure. The finish is semi-gloss, something I wouldn't want over gel-coat, but good for a less smooth base like epoxy-coated plywood.

Would I recommend it? I don't know. I don't think I'll use it on my sailboat. It's just too temperamental, and I'd like something shinier without the bother of a clearcoat or a lot of buffing. I'm not unhappy with my skiff. I've had better finish results with one-parts, but I'm hoping this stuff will stand up better to abrasion. I'm sure I could get better with more experience with it, as it's really a different animal than even solvent based 2-parts.

Use it in cool, damp conditions. They say "best results under 85F", I'd say don't think about it over 80 and stay in the shade even then. Work in small sections, don't be afraid to thin and apply a little thicker than you're used to. Foam brushes work OK, I tried a couple of various bristle brushes when I was having difficulty and they seemed no better. AT least with the foam, you can toss it if it gets gummy. I tried by wet & dry brush tipping, and had best results when I just used one brush for both edging and tipping as that kept it wet enough to not get gummy.

What I like best about this stuff is the short recoat time. Even on a 10' skiff, by the time you get all the way around, it's dry enough for recoat, so you can paint continuously. That alone might be worth the downsides of this product when I'm working in a distant boatyard and want to get it done in a day. It's just *very* important to have the right day!

Recommended with major qualifications.

Comments about System Three System Three - WR-LPU Linear Polyurethane Topcoat - Water-borne:

I think this is a great product for small boats built with epoxy. It's easy to use once you know how. It cleans up with water, and has almost no smell. You can paint in the basement, and your wife won't throw you out. It really saves time on boats glassed with epoxy, because you can paint right over the well sanded epoxy without priming. You do need reasonable temps to apply this paint, not hot and dry, but that would be hard with most paints. Use the very fine foam rollers sold at any paint or home store, and I use nylon bristle brushs from an art store. You don't need to use expensive brushes, but the they should be synthetic. Thin about 10% with water for rolling and tipping. Apply thin coats, and tip off vertically.The first coat over glassed wood won't look very good, but after 3 to 4 coats it looks great. It flows out nicely, and drys with a semi gloss finish, which nice if you are not trying to create work of art. Use interlux fine non skid particles mixed into the paint for decks. I'm just finishing a custom 17' tri I built, and it's coming out great! I painted a 22' cat I built a few few years ago with it and it looked good after three seasons out on a mooring.

Comments about System Three System Three - WR-LPU Linear Polyurethane Topcoat - Water-borne:

WR-LPU-review. First the good parts. There is almost no odor. It is easy to clean up with water and the polymerized paint is hard. Now the bad part. It rolls like bubble bath and gives wall to wall bubbles. When it is tipped with the best camel hair brush, you get twice as many tiny bubbles. With high humidity and cool temp, and a lot of luck, they may disappear when it is dry. If you tip with more than two or three swipes, it gets ropey and sets up that way. I put on four coats with the recommended West System roller, solid foam roller, short velour shureline roller and also the finest camel hair sign painters 3 inch brush. It never went on the same on any coat. Very frustrating. The brush was best.If worked too much with a brush you can get a fine herring bone pattern hours later when it dries when you thought you had a good finish. The non-polymerized paint was recommended for the first coats but adhesion was poor over sanded old polyester resin. When sanding, it did not feather out but suddenly came off in ribbons or sheets especially when you got near edges. With polymerization with each coat, it sands OK but with an 8 hour limit between coats you pretty much have to sand every coat-which I did. It fish-eyed and cratered for no apparent reason even on a second or third coat over a good coat. Go figure. It gets very hard and is difficult to sand when hard. I finished the job with a different finish. I really wanted to be able to use this water born finish for inside work but I was badly disappoined. I will still try using the polymerized WR-LPU clear gloss. I have been know to be stubborn.