Country: United States
Join Date: Dec 2015
Awlgrip vs. Awlcraft and Dark Color Issues
Color scheme issues aside, before you make your selections be certain you understand the differences between Awlgrip and Awlcraft 2000, as well as the potential issues associated with switching from a light to a dark color.
I ran a boat building and refit yard for 12 years, in which we did a great deal of paint application, primarily Awlgrip. Invariably, folks wanted the snazzy dark colors, Super Jet Black, Vivid Red, Aristo Blue and Jade Mist Green. There's no doubt they looked good. And as hard as I tried to talk folks out of these colors, I was nearly always unsuccessful. Other than aesthetics, there are no advantages to dark colors unless you live in a cold climate and want the boat to warm up. Nat Herreshoff once said, "You can paint a boat any color you like, but if you paint it anything other than white you are a fool". While those aren't my sentiments exactly, he has a good point.
The disadvantages to dark colors are...
Warmer cabin and resultant additional load on HVAC (If capacity is marginal it may be too much after the color change). Increased incidence of leaks. I've measured the temp of dark colored hulls and light colored hulls side by side, white or gray 90F, black or dark blue 130F. That heating, which is nearly always uneven, creating a banana effect, leads to substantial expansion and contraction of the hull and deck, which in turn stresses bedded hardware and leads to leaks.
Perhaps of the greatest concern is post curing. When a hull that's been gray or white all its life is painted a dark color, the resin post cures, it cures more than it has cured up to that point, which causes shrinkage, which in turn can lead to a phenomenon known as print through, wherein the warp and weft of the fiberglass fabric within the laminate, or the core material blocks, becomes visible as a sort of checkerboard or weave pattern. That's very unappealing and ruins the aesthetics many folks are seeking in a dark color. There are ways to prevent it when the vessel is being built, if the builder knows it's going to be a dark hull, and there are ways to deal with it after the fact, but they are costly.
From a paint application perspective, the best Awlgrip applicator I ever had was a guy who came to the yard to cut the grass. After he cut the grass he asked if there was anything else he could do. He was put on a hull fairing project, sanding with a long board, it's arduous work to say the least, and a good test of a new employees' resolve, some quit the first day, at lunch time. This guy, however, was different; he soldiered on and eventually graduated to more skilled surface prep. Eventually he asked if he could spray Awlgrip, which was met with the same sort of response Oliver Twist received when asking for more, heck didn't he know that Awlgrip applicators are born, they don't come up from the ranks?! However, in a boat yard, spray paint trades are among the positions most difficult to fill. He was ultimately given a chance and low and behold he was a natural, a really gifted individual. After watching him for do his magic for several years I determined the secret to his success. Like celestial navigation, Awlgrip and other two part paint application is part science and part art. He was born with the art part, he could make a spray gun sing. However, he committed himself to learning the science by reading and thoroughly understanding every piece of literature produced by Akzo Nobel, the manufacturer of Awlgrip and Awlcraft. This involved surface prep, temperature, humidity, and catalyst protocols. Over the years I've seen many who were born with the skill to apply paint, but neglected to educate themselves where the science was concerned, with predictable mediocre results, which are invariably blamed on the paint. The message here is, it's all about the applicator and his or her skills and understanding of the product.
Beyond the color issue, there is a substantial difference between traditional Awlgrip and Awlcraft 2000. The former is linear polyester urethane that is extremely durable, abrasion, weather and UV resistant. It was originally developed for use on aircraft. Depending on the region, I've seen light colors last and look great for upwards of 20 years, and dark colors for 15 years. It requires exceptional skill and experience to apply and repair. Awlgrip has a thicker resin layer that gives it its durability, however, this layer prevents scratches, drips and runs from being easily buffed out while retaining long lasting shine and performance.
Awlcraft 2000 is an acrylic urethane, it was developed by Akzo Nobel to be easier to apply by less skilled applicators. It dries quicker, which reduces the likelihood of dust and insect entrapment. Because of its softer finish, a result of the less dense molecular structure, it has a lower melting point, thus when buffed, the coating can be made to flow, making repairs much easier.
Polyester molecules (Awlgrip) are much smaller than acrylic molecules (Awlcraft), which means for a given volume the polyester coating is denser, and thus more abrasion and chemical resistant, and has better color retention.
Awlgrip can be brushed, Awlcraft 2000 cannot. Both stratify, leaving a resin rich layer at the top, with a pigment rich layer beneath, which is one of the reasons they are long lasting. Awlgrip's layer is thicker than Awlcrafts, which is why it's more durable and more chemical resistant, and why it's more difficult to repair. Any buffing or repair that reduces the resin film thickness will compromise longevity and durability, as well as potentially affecting the warranty.
In order to repair a scratch for instance in Awlgrip, buffing or sanding, known as "cutting" must go deeper, penetrating the pigment layer. The resin layer is thicker and less able to flow or melt, filling the scratch or damage. Initially the repair may look shiny, however, if it's exposed the pigment and no longer has a clear coating, it will eventually dull, which means it will require regular application of Awlcare, a protective polymer coating that restores gloss, temporarily. This peculiarity of Awlgrip makes the edges of painted repair areas more difficult to blend.
Awlcraft's thinner, less dense, less cross linked, softer and more "flow-able" surface resin layer makes repairs easier. This makes it possible to carry out repairs that do not expose the pigment, because the surface resin layer melts and flows without exposing the pigment. It also makes touch up blending easier.
Even though Awlcraft 2000 is easier to repair, I've seen many repair jobs botched, primarily because unskilled or inexperienced operators use too much pressure, or to many rpm on buffing wheels, causing excessive resin melting or cutting too deeply, exposing pigment.
Today, many yards use the terms interchangeably, which is misleading. These coatings are very different animals, each with their own sets of advantages and disadvantages. If ease of repair is of the greatest importance to you, go with Awlcraft 2000, if longevity and durability is more important, and especially if you opt for a dark color, go with Awlgrip.
Above all else, vet the yard that will carry out the work carefully, among other things ask for references that include recently painted vessels as well as those that are five or more years old, preferably painted by the same painter who will lift his or her gun to your hull.