The Awlgrip Advantage - Text-only Version

You are reading the text-only copy of this article. To access the article as it appeared in PassageMaker Magazine, please log in to purchase and download the PDF version of this article.

A few months ago, my colleague and PMM’s editor-in-chief, Bill Parlatore, approached me about painting an 18-foot Little River rowing skiff he had recently acquired. (You may have already read his accompanying article, “Colors,” in this issue.) At the time, Bill asked that alltoo- familiar question, “Steve, what’s involved in painting my rowing skiff?”

While Bill’s rowing skiff is considerably smaller than any trawler I’ve ever painted, the paint preparation and application process is identical. In what follows, you won’t learn all there is to know about Awlgrip and how it’s applied. That takes years of experience and long hours of sanding, fairing, and spraying; however, you will learn enough to help you decide whether Awlgrip is the right approach for your boat. I’ll also share with you a few tips that will assist you in selecting a yard for your Awlgrip project.

THE DEVIL AND HIS DETAILS

Awlgrip and other two-part linear polyurethane, or LPU, paints are ideal for coating comparatively stable substrates such as fiberglass, steel, and aluminum. (Because most cruising trawlers are fiberglass, I’ll concentrate on that material.) In fact, Awlgrip was originally developed to coat commercial and military aircraft fuselages. Awlgrip is, however, less than ideal for coating wood—–unless it’s cold molded. (Cold molding is a form of boatbuilding that fully encapsulates wood in epoxy and reinforcing glass fabric.) Because of its propensity to absorb and relinquish moisture based on the environment in which it is used, wood is forever expanding and contracting—–and that’s an almost certain recipe for failure. It’s important that Awlgrip be applied to structurally stable, dry, and contaminant-free surfaces. Wood, as aesthetically desirable as it may be, just doesn’t meet these criteria.

Awlgrip is designed to chemically react with its associated catalysts, reducers, and primers. When Awlgrip is mixed in the proper ratio with its catalyst, a chemical that causes the topcoat (surface paints, the part you see when the job is complete, are often referred to as topcoats) to harden, the molecular chains within the paint intermingle. These molecular chains then solidify, creating that hard, reflective, plastic-like finish that is impervious to most chemicals, including gasoline and diesel fuel. Using incompatible chemical components will result in an undesirable reaction. For instance, if a paint applicator were to use a primer or filler to fair surface irregularities and the primer or filler was not chemically compatible with the Awlgrip topcoat, a reaction may result that causes an adhesion- or blistering-type failure. Therefore, it is strongly recommended that all coating products, primers, topcoats, fillers, thinners, catalysts, and so on be supplied by a single manufacturer. Most two-part paint manufacturers, such as Awlgrip/US Paint, offer complete “coating systems” that allow the applicator to use products that are guaranteed to be compatible.

There’s little doubt that where hulls are concerned, dark colors—–hues of blue, black, green, and red—–are “in,” and white is, well, simply not as popular as it once was. When folks come to my boatyard to discuss an Awlgrip application, they’ve usually already chosen a color, and it is almost invariably one of these darker pigments. I do my best to change their minds, and here’s the argument I usually present against using dark colors. Vessels painted dark colors will develop substantially higher surface temperatures. How hot can they get? I’ve measured dark-blue hulls in Virginia’s July sun as hot as 170 degrees, while a neighboring white hull measured just 90 degrees. In the tropics, you can expect even higher temperatures. The effects of this superheating are manifold. The accommodation spaces will be warmer, and so will the occupants. The air conditioning (and refrigeration), if the vessel is so equipped, will be turned on sooner, will have to work harder, and may require more Btu capacity than a unit installed in a light-colored hull.

In the case of fiberglass construction, another and perhaps more compelling reason for giving careful consideration to paint color involves a phenomenon known as post-curing. When a fiberglass hull or deck is built, the resin dries or cures, and as it does so, it shrinks. Typically, this shrinkage is slight and thus not very noticeable in the finished product. If, however, the resin is heated, it tends to shrink even more. When this post-curing occurs, the crosshatched fiberglass fabric reinforcement used in the construction process will often become visible on the surface of the laminate, creating an unsightly burlap-like appearance.

In some cases, a builder may intentionally post-cure a fiberglass laminate to create this shrinkage and force this weave pattern to appear on the surface. The surface can then be faired, primed, and painted over, at which point the surface pattern is typically never seen again. Once the post-curing process occurs, the laminate will not shrink any further, unless it is heated beyond the temperature at which it was post-cured. In other cases, builders may use a special fluffy type of fiberglass reinforcement that is less likely to telegraph the weave pattern through the resin, which negates the need for post-curing.

Superimpose what you now know onto the color selection process. Your current hull is white; but, in spite of your boatyard manager’s strenuous arguments to the contrary, you’ve settled on a shade of blue. On a hot day, your light-colored hull’s temperature never rose above 100 degrees. Once it’s dressed in dark blue, however, it may reach temperatures closer to 200 degrees. With this rise in temperature, the resin within the laminate will post-cure. Remember, the hull is getting hotter than it’s ever been before, and the result will be shrinkage. With this shrinkage, you run the risk of exposing the glass reinforcement’s weave pattern.

Having made all of these arguments to you, the reader, and countless Awlgrip customers, I’m rarely successful in talking folks out of the dark color on which they have their hearts set. If that’s the route you choose to take, and your hull was originally white, either be prepared for the possibility that postcuring will induce surface irregularities or be prepared to intentionally post-cure and then fair over the irregularities before the paint is applied. The latter approach, while sometimes costly, will nearly always result in a higher quality, more brilliant, blemish-free coating. If your hull was a dark color and you are painting it the same or another dark color, you, and your boat, are in luck, because in this case the surface is unlikely to suffer from the effects of post-curing.

THE FIVE Ps

Proper planning prevents poor performance. Although this axiom is universally applicable within the world of boatbuilding and repair, it’s especially pertinent where the subject of Awlgrip is concerned.

Damage, cracks, crazing, post-cure crosshatch, and other defects in the surface that is to be coated must be properly dealt with to prevent their reoccurrence. Awlgrip and its associated primers tend to magnify defects with each successive coat, so it’s important that these problems be resolved before a topcoat is applied. Some sprayed primers, known as high builds, are designed to fill shallow defects. However, these coatings are no panacea. After they have been applied, the surface must be carefully sanded to remove the primer from the area surrounding the defect that has been filled. Deeper defects must be ground out using a pneumatic or electric grinder, then filled with a thicker, troweled-on, filler/fairing compound, and—–once again—– carefully sanded.

Gelcoat cracks often present a vexing problem for the Awlgrip applicator. On older vessels or on vessels whose gelcoat may have been applied too thickly, cracking will often occur. How long this reappearance will take varies; it may take a week or it may take a year, based on the depth of the crack, the causes of cracking, and the flexibility of the substrate.

There are two methods of dealing with cracks. The first calls for widening the crack, then filling the void with fairing material and sanding it smooth. This approach is sometimes successful, while at other times it’s not. If the area where the crack occurred is experiencing a great deal of movement or flexibility, the fairing material may develop its own cracks. Or, if the crack extends into the fiberglass laminate, it will almost certainly reappear regardless of the filler. These cases may call for more drastic action, such as deep grinding and then adding fiberglass reinforcement before filling the area with fairing compound and sanding it smooth.

The second method calls for the wholesale removal of the most common cause for the cracking: the gelcoat itself. If the hull or deck that is to be painted is suffering from uniform or numerous cracks, the time required to individually attack each one of these cracks will be excessive, while the likelihood of achieving a long-lasting fix will be questionable. In these cases, it often makes sense to remove the gelcoat, sand, fair, prime, fair again, and then apply the topcoat. Fortunately, Awlgrip is considerably more flexible than gelcoat, so even if the substrate is flexing or moving, it’s unlikely that the Awlgrip will crack the way the gelcoat did. While neither of these approaches guarantees a permanent fix to the cracking problem, replacing the gelcoat with Awlgrip has a much greater likelihood of long-lasting success.

The final area worthy of some consideration when discussing preparation for Awlgrip application involves the subject of hardware removal. The ideal coating application is one that is contiguous, with as few seams as possible. If deck and other hardware—–cleats, stanchion bases, fuel fills, boarding ladders, and swim platforms—–are masked off rather than removed, scores of seams will be introduced into the painting process, and therein lies a problem. As durable as Awlgrip is, if it’s going to fail, it’s likely that it will fail at a masking seam. The reason for this is that water tends to accumulate at hardware installations, and water, being the universal solvent, will eventually find its way beneath this paint seam, causing the coating to lift, blister, and otherwise fail.

Although it may initially be more costly, it’s desirable to remove as much hardware as is practical in preparation for painting. An additional benefit of hardware removal is the opportunity to renew the associated bedding or sealant. Common wisdom dictates that bedding shouldn’t be relied on to remain watertight much beyond about 10 years. Since most boats that are potential candidates for repainting are more than 10 years old, it’s probably time that the hardware bedding be renewed anyway. While the hardware is off, deck core penetrations can be inspected, repaired, or improved. The time taken to remove, rebed, and replace hardware will make for a significantly higher quality and longer lasting paint application.

CHOOSE YOUR PROFESSIONAL CAREFULLY

Once you’ve decided to go ahead with a painting project, you must next choose the yard where the work will be performed. Like so many other servicerelated decisions, reputation is important. Word of mouth and recommendations should be part of your decision-making process. Once you’ve narrowed down the field, visit the yard and ask to speak with the manager. Discuss the techniques and approach the yard takes toward preparation of your particular surface, whether it’s existing paint or just old gelcoat. (If it’s paint, will they perform a solvent and adhesion test? If it’s gelcoat, what’s their approach toward crack repairs and porosity—–a problem that often plagues older gelcoat?)

Ask for references. Ideally, you should inspect at least two boats that the yard has painted, and at least one of these paint jobs should be more than three years old. Look for the obvious paint flaws: drips, runs, a lack of gloss, and sags, as well as dust, dirt, debris, and insects that have been entombed within the paint. Fish eyes—–the bane of all marine paint applicators—–are oval-shaped irregularities in the painted surface that are usually no bigger than a pencil eraser. These are caused by a failure to properly clean, degrease, de-oil, or dewax the surface before primer or paint is applied. Sharp painters know how to prevent fish eyes, so make sure the painter you choose does. Also, look for an effect known as orange peel, a mottling or roughness in the paint that looks like an orange skin, that is usually caused when the paint is applied too thinly or too dry. Look for the telltale signs of inadequate preparation, which often manifest themselves in the form of sanding swirls (from an orbital sander) or gouges (caused when the operator of an orbital sander holds the tool on its edge rather than parallel to the surface) beneath the paint. These are signs of a paint crew rushing the job, or just plain inattention to detail.

Once they have inspected your boat, the yard should be willing to provide you with a quote for the paint project. I use the word “quote” because that’s my preference—–a fixed price. However, many yards are reluctant to enter into this type of contract. At the very least, you should get an estimate, but be sure you understand what getting an estimate means; laws governing its definition vary from state to state. Whether it’s an estimate or a quote, ascertain just what the word means to the yard. Is there a price range? (There shouldn’t be in the case of a quote.) What variables or contingencies may be included, and when might the project revert to a time-andmaterials mode (if, for instance, unexpected damage or flaws are discovered in the preparation process)?

LITTLE RIVER PROJECT

As mentioned at the beginning of this article, while Bill’s Little River skiff is just 18 feet long, applying Awlgrip to her hull was similar to applying this coating to a larger vessel. In her case, because she was originally gelcoated white and her finished Awlgrip topcoat would be green, I advised Bill that what was needed was a controlled post-cure. With input from the boatbuilder and the resin manufacturer, the paint crew built a tent around the hull and heated it to achieve the desired degree of post-curing. On completion of the post-curing, the slight weave-like ripple of the underlying fiberglass cloth made its appearance. A high-build Awlgrip primer was then applied and sanded, which filled in the valleys between the ripple peaks, leaving behind a smooth surface ready for topcoat. Four coats of Awlgrip were applied, using varying dilutions of thinner, along with a final clear coat for added gloss retention and durability.

The results were predictable for an Awlgrip application—–a deep, lustrous shine and gloss retention that will require no more than the occasional washing. The manufacturer of Awlgrip neither requires nor recommends the application of wax or polish, because the finish retains its glossy appearance without these products. However, the manufacturer does offer Awlwash and Awlcare products. The former is a detergent that is designed to safely wash Awlgrip paint, while the latter is a polymer sealer designed to protect new Awlgrip and restore the shine of Awlgrip that has either been damaged as a result of harsh treatment or become porous due to old age.

There are many ways to improve or change the appearance of your boat. Few, however, have as dramatic an effect as a professionally applied Awlgrip application. Whether it’s a new vessel or one that has a few miles under her keel, Awlgrip may be the way to give your boat that custom appearance, something that differentiates her from her sisterships or restores her to her showroom finish (or maybe even a little bit better). As far as Bill’s rowing skiff is concerned, with her custom Awlgrip Laurene Green finish, she’s now one of a kind.

Steve D’Antonio is PMM’s Technical Editor and the VP of operations at Zimmerman Marine, a custom boatbuilder and full-service repair yard in Mathews, Virginia.

Reprinted with permission. Copyright 2006 © Dominion Enterprises (888.487.2953) www.passagemaker.com

You are reading the text-only copy of this article. To access the article as it appeared in PassageMaker Magazine, please log in to purchase and download the PDF version of this article.