Fiberglass Hull Restorers : 21-month Report

Of the DIY products tested, Poli-Glow, New Glass and Vertglas show the most gloss and last longest. Professionally applied Microshield is even better, but costs more.


Remember when your boat was new? Chances are that if youve had it for more than a few years, the once-shiny gelcoat has become dull and, if it were a color other than white, faded and a bit blotchy looking. The past few years have seen a proliferation of products designed to bring back the new, glossy look to weathered topsides. These hull restorers are typically more durable than waxes though less durable than a high-quality paint. Most of these products are also less expensive and easier to apply than paint.

Weve been conducting tests on eight such products (we originally had a ninth, but it has been discontinued) for the past two years, with more than 21 months of actual exposure to the elements. We looked at them after a year of exposure (PS, July 1, 1998), re-applied the restorers-they don’t claim to last for more than a year or so with a single application-and put them back out to weather.

To reiterate what weve said previously, these products are best thought of as temporary fixes. All of them can dramatically improve the appearance of a weathered fiberglass surface, but youll probably have to plan on yearly applications. Our current tests are set up to answer two basic questions about these products: a) can you successfully re-coat the surface without stripping off the old product? and b) how difficult is it to remove the product?

How They Work
Theres nothing mysterious about restoring the appearance of a fiberglass surface. When the boat is new, the gelcoat is very glossy and has a uniform color. After exposure to sunlight and weather, however, the outer surfaces of finely divided particles of opaque pigment that are suspended in the resin change color from the effects of UV and oxidation. Degraded pigments tend to become lighter in color, turning a yellowish gray. Because not all surfaces are exposed to the same sun and weather conditions, the color becomes blotchy as well as faded. At the same time, UV and weather cause the smooth surface of the gelcoat to become microscopically pitted. A smooth surface appears glossy because almost all the rays of light that strike the surface are reflected back in the same direction; a pitted surface scatters the reflected light, and appears dull.

Restoring the surfaces appearance, then, involves two things: removing the discolored outer layer of pigment (its not feasible to reverse the weathering process) and providing a smooth surface to restore gloss. Removing the outer layer of the pigment is a mechanical operation involving scraping or grinding off the surface layer with an abrasive. Sandpaper would work, but its generally too coarse for the job, making the surface smooth a much more difficult task. The more usual approach is to use a very fine abrasive powder suspended in a liquid. If the abrasive is extremely fine, the mixture is called a polish; if the abrasive is somewhat coarser, its called a rubbing compound. The more severely weathered the fiberglass, the coarser (and therefore more aggressive) the abrasive should be. Slightly weathered topsides respond well to polishes; more severe weathering calls for compounding, followed by polishing. The objective, of course, is to obtain a uniform color.

Once the color is uniform, the next step is to keep polishing the surface until its as smooth as possible. Its almost impossible to obtain the microscopic smoothness thats required for a high gloss, but its a good idea to remove as many small gouges and scratches as possible. The next step is to apply a transparent film that will fill the microscopic pits and valleys, leaving a smooth surface.

Water will do the job for a very short while, until the water evaporates. The trick is to find a material that will keep that wet look for an extended period of time. Wax is the classic choice. It does a pretty good job of providing a smooth surface, and lasts for a good bit longer than water. In our experience, a typical wax job will last about three months. Some wax products-those that contain harder, higher-molecular-weight waxes-can last up to about six months. These are usually paste waxes rather than liquids, and are correspondingly more laborious to apply.

Fiberglass restorers use even higher-molecular-weight ingredients-acrylics or acrylic-urethane resins-as film-formers. These products consist of water-based emulsions of droplets of resin. When the water evaporates, the resin coalesces to a clear film thats insoluble in water. The emulsions have low viscosities-much like water or liquid floor waxes-and dry rapidly. These characteristics make for easy application, but also mean that relatively little film is left after one application. Multiple coats are required, but the low viscosity means that application is easy and the quick-drying means that you don’t have to wait for more than a few minutes between coats.

Instructions for the products we tested typically call for about five initial coats, with three maintenance coats at the end of each year.

What We Tested
The eight products were testing were selected after an exhaustive canvassing of boat shows, chandleries and catalogs. We looked for any product that claimed to restore fiberglass and wasnt a wax. We found seven do-it-yourself (DIY) restorers and one thats only marketed as a professionally applied product.

Most of the products are sold as kits-cleaners, strippers, polishes, and final coat, or some sub-set of these. Most come with applicators and instructions of varying levels of detail; one even comes with an instructional video, which seems to us to be carrying things a bit far. From our experience, all of the products are reasonably easy to use. The one caution wed emphasize (for all the products) is that the surface be clean and of a uniform color before you apply the clear topcoat.

The Tests
This years testing was a continuation of a program started back in 1997. At that time, we took a series of well-weathered fiberglass panels that we had sawed from the hull of a wrecked sailboat, and applied each hull restorer to a panel following manufacturers instructions. In the case of Microshield, the only dealer-applied product, we sent a panel to the manufacturer, who applied the product. Prior to restoration, all the panels were mottled, with a dead flat surface exhibiting no trace of gloss. After restoration, all had been dramatically improved. Before exposing the panels to the weather, we tried placing a drop of water on each panel (a panel thats protected will cause the water to form a distinct bead, rather that spreading out to a shallow puddle). We also made judgments about each panels appearance, and then measured the gloss level of each, using our own gloss measurement system which has worked well for us in the past. We made a mirror-image yardstick-actually only 2 feet long-and placed it perpendicular to the panel that was to be measured. We shone a light on the ruler, using a constant light source and a constant angle of illumination, and looked at the yardsticks reflection in the restored panel. The glossier the surface, the more of the yardstick scale was reflected, and the higher the number that could be read.

We then placed the panels outdoors on south-facing racks tilted to 45, and left them there, observing their appearance periodically. After a year, we took the panels off the rack, washed off surface dirt with a soft brush and a solution of liquid dishwashing detergent, and tested for beading and measured the gloss again. We then divided each (except for the Microshield-treated one) in half and applied three maintenance coats to half the panel, without removing the material that had been previously applied. We stripped the other half-panel down to bare fiberglass using the stripper provided with each product or, if no stripper was provided, with the stripper from another product. We then re-applied fresh restorer per instructions (usually about five new coats).

We didnt do anything to our Microshield-treated panel. The product claims eight years of protection, and, in any case, we didnt have any material to recoat it with, because the panel was prepared by Microshield and not by us.

Our reasoning was simple: Its certainly easier to add maintenance coats to an existing product, but we wished to find out if we could get a better appearance by stripping and re-coating. We also wished to see if stripping was difficult, as some readers have reported.

The panels then went out to their racks again. Our test season was shortened somewhat by the necessity of moving our test racks from Connecticut to Newport, Rhode Island (our landlord in Greenwich, Connecticut, wanted his roof back), but we did get nine months of additional weather testing.

The Results
To summarize the findings in last years report, all the panels still beaded water after a years exposure, gloss had declined on all panels and all (except Microshield, which we didnt try) stripped easily. Microshield emerged with the highest gloss, followed-at a distance-by New Glass and Poli-Glow. TSRW and Vertglas also showed some gloss retention, while the other products had all but vanished, at least in a visual sense. The one wax tested-the now discontinued Boat Armour Microshine-gave up after a few months as far as gloss was concerned, and wouldnt cause water to bead after six months. Dont be misled by the gloss numbers; even a minimal gloss (such as 1) is a vast improvement over no gloss at all.

We found that all the products stripped easily, with the sole exception of TSRW (whose QuickStrip didnt live up to its name, convincing us to finish with New Glass Stripper, which worked well). Sea Breeze didnt come with a stripper, so we used Vertglas stripper. We reported previously that Poli-Glow doesn’t come with a stripper. It does, and we tried it on another section of the panel, where it worked well.

We also found that one can get about the same gloss after applying three maintenance coats to the weathered surface as we did when stripping the surface and starting from scratch.

This year, after an additional nine months, the results compare to last years on both re-coated and stripped-and-recoated halves of the panels. Microshield is still holding up very well after 21 months. Last years two winners in the DIY class-New Glass and Poli-Glow-again led the pack with respectable gloss retention. They were joined by Vertglas. When we first tried Vertglas we had applied it with a cloth, rather than a sponge applicator. For the re-coating of the panel, we practiced with Vertglass brush/sponge applicator and obtained both a much better initial gloss and a longer lasting gloss.

Except for one product-Sea Glass Sea Protector-we could discern no real difference between the panel halves that had been simply recoated and the ones that had been stripped and re-coated. The recoated side of the panel treated with Sea Glass Protector seemed a bit more milky in appearance than the side that had been stripped before recoating.

The best of these products work. Theyre not magic, though. If you insist on having your boat look new, the surest way is to buy a new boat frequently. Two-part polyurethane paints, such as AwlGrip, Imron and Interthane, will do a fine, long-lasting job…at a price. A paint job with one of these paints will probably run you about $100-$200 per linear foot, if applied professionally. Expensive, yes, but in our opinion, a boat with faded gelcoat is a good candidate, sooner or later, for a paint job. Fiberglass restorers simply postpone the job and expense.

Intermediate in cost as well as (probable) durability is Microshield. The cost of a Microshield job will depend on the size and style of your boat; we couldnt get a simple estimate from the manufacturer. If youre interested, youre best off contacting them directly.

The DIY restorers generally sell for $35 to $60 per kit, which will handle a 25-foot boat. New Glass, Poli-Glow or Vertglas, our longevity winners should provide reasonable gloss for a season in most climates. Application of three maintenance coats once a year should keep the boat glossy, if not quite new-looking. They all dry in minutes, so you can re-coat by working your way around the boat and just keep going until youve completed three circuits.

Weve heard scattered reports of some of these products going milky, yellowing, flaking or cracking, as well as reports that stripping is difficult. In six years of testing products of this type, weve never encountered any of these problems. Weve applied restorers to a variety of small craft that live outdoors, with no signs of trouble. This year we stripped a Sunfish sailboat that had been receiving maintenance coats of New Glass for the past five years. It stripped easily.

The one report we havent been able to check out is that of yellowing. Unfortunately, the wreck from which we carved the test panels had a yellow gelcoat. For this year, were planning on adding some new panels in white and/or red.

Should you use a fiberglass restorer on a new boat to provide added protection? We think not. Youd have to sand or scuff up the pristine surface to get the restorer to adhere well. Wax is a better choice.

For older boats that have become dull and streaky, however, fiberglass restorers offer an economical, inexpensive means of making your boat look shiny again, and keeping it that way for a reasonable period of time without an exorbitant amount of effort. Our picks are Poli-Glow, New Glass and Vertglas, with TSRW close behind. Microshield is still the most effective product weve found to restore gloss to an old boat. If it holds up for a few more years, its higher price tag may well prove to be worth it.

Contacts- Microshield, Marine Resources, 1651 Browns Rd., Suite 101, Baltimore, MD 21221; 410/687-7293. Sea Breeze, Rolite Co., 596 Progress Dr., Hartland, WI 53029; 414/367-2711. Vertglas, Lovett Marine, 682 W Bagley Rd., Berea, OH 44017; 800/636-7361. New Glass, KAS Marine, 6 Lago Vista Pl., Palm Coast, FL 32164; 904/829-3807. Sea Glass, Port of London, 6101 Dory Way, Tampa, FL 33615; 813/855-5983. TSRW, Edgewater Distributing, 55 NE Bridgeton Rd., Portland, OR 97211; 503/282-7006. Higley, Higley Chemical Co., 40 Main St., Dubuque, IA 52001; 319/557-1121. Poli-Glow, Poli-Glow Products, 15476 NW 77th Ct., Miami Lakes, FL 33015; 800/922-5013.

Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida.


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