Gelcoat Restoration: Back From the Dead

We used hull restorers from Vertglas, Poli-Glow, and New Glass-2 to revive a beaten and battered powerboat, and included Collinite’s Fiberglass Boat Wax as part of the test, too.


In the January 1 issue, we reported the beginning of a long-term wax test. Included is a product called Poli Glow , which is actually not a wax but a “hull restorer” that has tested well for us before, and that continues to get good reviews from readers. 

Gelcoat Restoration: Back From the Dead

Then we decided it was time to face off the hull restorers again. Initially, we were going to stick to restorers only, but Nick Buchanan, proprietor of Scuba-Do Yacht Detailers in Sarasota, FL, assured us that he could bring back a fiberglass gelcoat the old-fashioned way, with wax. So we decided to include a wax, too, thus making sort of a mirror-image experiment to go with the wax story.

Nick recommended Collinite #925 Fiberglass Boat Wax, a liquid wax. This worked out well, since we’re already testing Collinite #870 liquid Fleetwax and Collinite #885 paste Fleetwax. The #885 is editor-at-large Nick Nicholson’s favorite wax.)

For a test boat we used a 21-foot Neptune outboard owned by our colleagues at Powerboat Reports. The boat, to our knowledge, had never been cleaned, inside or out. It has never been about looks—only purpose, and it gives a whole new meaning to the phrase “gone fishin’.” It was the floating version of Oscar Madison’s bedroom: Fish blood and rust stains, grease, grime, and dirt covered the cockpit from gunwale to gunwale. Scuffs and stains grubbed up the gelcoat, which was also chalking and fading fast.

Abandon ship? No way. We forged ahead, determined to whip this bad boy into shape.

Here’s our initial report. Six months from now, we’ll tell you how the contestants are holding up under the Florida sun. 

What We Tested
In the April 15, 2000 issue of Practical Sailor, we recommended three products as fiberglass hull restorers: Poli Glow, Vertglas, and New Glass-2. These wipe-on coatings consist of resins of higher molecular weight that provide harder and more durable film than can be achieved with wax. The products tested consist of water-based emulsions of acrylic or acrylic/urethane resins. The resins are in the form of tiny droplets that are suspended in water. When applied, the water evaporates and the droplets flow together to form clear films. These emulsions dry rapidly and require multiple coats. The restorers require re-application about every 12 months.

The test was a simple one: We divided the boat into three sections and each restorer was applied to a section. As for the wax, Nick Buchanan wet-sanded, applied rubbing compound, and then waxed the top of the cuddy cabin and a small section of the transom with the Collinite.

We realize that different areas of the boat have endured more of a beating from the sun than others. For instance, the flared sections of the bow are somewhat more protected from the sun than the flat sections of the hull sides and the cabin top. We tried to be evenhanded in our applications of the products, but will report any inequities in procedure as they become apparent. Meanwhile we can focus in this report on the ease of application, cost, and the amount of time it takes to apply each. 

What We Found
All three hull restorers make it clear that surface preparation is essential to their product’s success, meaning that if you miss a streak or stain, that streak or stain will become embedded under the hull restorer. Not good.

So, we were very careful to get rid of all stains, surface scratches, and abrasions. Our applicator for the hull restorers did a meticulous job cleaning the hull. And it was challenging. She had to be careful not to smudge the ablative bottom paint and taint the gelcoat.  

New Glass-2
This product is the least expensive of the three. For $47.95 (plus $5 shipping in the US), you get two bottles—one is the actual hull restorer and the other is a stain remover—and an 8″ x 5-1/4″ cloth.

The directions, which are printed on a paper bottle label, say to use a heavy-duty cleaner to prepare the surface. We used West Marine heavy-duty boat soap.

To activate the stain remover, you add water to the bottle, which is easy enough. But the print on the bottle label smeared when it got wet, making parts of the directions hard to read. Our tester also pointed out spelling errors on the bottle. Since it’s never a good idea to criticize errors of a kind to which one is susceptible, we declare these spelling errors to be absolutely no big deal. In addition, New Glass-2 founder and owner Kurt Schenholm said he’s working on the print-smearing problem.

We found the stain remover directions a bit unclear because they don’t fully explain how to use the product—only to squirt it on and keep the area moist for about one minute or “until stain disappears.” (Do you use a scrubbing pad, cloth, sponge?) We squirted it on and let it sit for the required minute. Nothing happened. We used a scrub brush, but it had no effect.

Before we resorted to another cleaner, we gave the New Glass Stain Remover one more shot, applying it with a scrub pad and waiting two minutes. Same result. The directions do say the product removes “rust and brown waterline stains.” Schenholm said it should have worked and added that we might have gotten a bad batch. He planned on sending us another bottle. We’ll try it again and let you know what happens.

Gelcoat Restoration: Back From the Dead

In the end, we used Poli Glow TLC Marine cleanser, a powder that contains acid, and that did the trick.

On to the New Glass-2 restorer. The directions were a bit vague, in our view. They stress thin and multiple layers but fail to specify a number of coats, at least for a fiberglass surface. If applying to metal, the directions do recommend four coats.

The applicator is merely a small square piece of cloth. Its size made it harder and more time-consuming to evenly distribute the restorer. Schenholm said he has just introduced a second applicator, which is a piece of PVA cloth wrapped around a circular section of pipe insulator. This makes it easier to apply the product to the curved sections of a hull.

New Glass-2 is the only restorer that instructs the user to apply a coat of wax after the restorer is applied. Schenholm said any type of wax will do. The wax may extend the life of the restorer by a couple of months, he said.

Bottom Line: It’s the least expensive product, and our original application looks very good. Its drawbacks, in our view, are its unclear directions and inadequate applicator. 

Poli Glow
The directions were very clear and thorough. For instance, you’re reminded to take into account the air temperature and the drying time, and apply a minimum of four to six coats, with one minute drying time between coats. You get three applicators: a large block that can be fastened to any threaded pole, a small handheld, and a small loose cloth.

Poli Glow directs the user to apply its cleaner with a pump sprayer (not included). The cleaner worked well, except for the tough scuff stains. For those, we used Poli Glow’s aforementioned cleanser.

If you have a lot of stains, you might want to skip the boat soap and just use the TLC cleaner. Remember, though, it does contain acid.

A couple of notes about Poli Glow’s application: 1) The small handheld applicator had a layer of lint and loose particles on it (right out of its baggie), so when the tester applied the product, those pieces of lint and particles were spread onto the hull. With cat-like quickness, she removed them before the product dried. 2) Poli Glow tells you to make sure to keep the applicator moist. If the product dries on the applicator, flakes will form. And those flakes can muck up the job. We encountered said flakes and had to clean the applicator and change gloves.

Bottom Line: The product has a lot going for it: clear directions, a nice variety of applicators, included boat soap and an acid-based powder that worked well. You will need to povide the spray pump. We did encounter some flaking. 

Application of Vertglas is done in four steps, using four different bottles of product. An anti-oxidation liquid is applied first, and it did take care of the chalkiness. This product, which contains calcium carbonate and magnesium carbonate, also removed scuffs and stains.

Step 2: Clean the boat with Vertglas boat wash. It worked well, and the directions were thorough and clear.

Step 3: Our tester appreciated the lengthy and clear directions. For instance, she pointed out that Vertglas was the only one to tell her whether to shake the product. (Don’t shake it.)

Step 4: Vertglas is one of two kits—the other is Poli Glow) that provides a product to remove its gelcoat restorer. We plan on testing it later.

Directions call for six to eight coats. We applied seven (smart, right?). The directions said streaking would stop after the first coat, and it did. The large 10″ applicator made the job more expeditious, but its flat straight edge made it hard to follow the contours of the hull and apply it evenly.

Bottom Line: Most expensive of the three, but all the elements of the product worked very well, including the prep solutions. The package could use a variety of applicators, however. 

Collinite #925 Wax
Nick Buchanan has tried just about every wax on the market, and, like Practical Sailor, he thinks highly of Collinite.

As with the hull restorers, preparation of the surface is key. Buchanan wet sanded with a 1500-grit sand paper, then used Aqua Buff 2000 rubbing compound, followed by Collinite #925 Fiberglass Boat Wax. He applied everything by hand.

Bottom Line: It will be interesting to see how this detailer’s pick, skillfully applied, stands up against the hull restorers under the same conditions. 

Gelcoat Restoration: Back From the Dead

Talk about night and day. The boat looks brand new—at least the sides, the cabintop and a 2’x2′ section of the transom. We can’t really tell the difference between the hull restorers—yet. So our initial conclusions come down to application.

Our tester puts Poli Glow at the head of the pack because of its variety of applicators, effective cleanser, and clear directions. The Vertglas could use additional applicators. The New Glass-2 needs a larger applicator, and its stain remover did not work for us.

The sections waxed with Collinite look good, too, although the hull restorers gave the boat a higher gloss, to our eyes. The good news is that it’s tough to botch a wax job. There’s much more room for error when working with hull restorers, and hull restorers are tougher to remove.

In our April 2000 report, we mentioned “occasional complaints from readers that hull restorers can give the hull a yellowish cast.” We’ll see if that develops over the coming months.


Also With This Article
“Value Guide: Gelcoat Restoration”
“Getting It Off”

• Aqua-Buff 2000, 802/824-3954,
• Collinite, 315/732-2282,
• New Glass-2, 904/829-3807,
• Poli Glow 800/922-5013,
• Scuba-Do Yacht Detailers, Sarasota, FL, 941/587-0060,
• Vertglas, (Lovett Marine), 800/673-5976,

Practical Sailor has been independently testing and reporting on marine products for serious sailors for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising or any form of compensation from manufacturers whose products we test. Testing is carried out by a team of experts from a wide range of fields including marine electronics, marine safety, marine surveying, sailboat rigging, sailmaking, engineering, ocean sailing, sailboat racing, and sailboat construction and design. This diversity of expertise allows us to carry out in-depth, objective evaluation of virtually every product available to serious sailors. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser with more than three decades of experience as a marine writer, photographer, boat captain, and product tester. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.


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