Features March 1, 1998 Issue

I Can See Clearly Now: Cleaners For Plastic Windows and Ports

Plexus is great for regular maintenance and small fixes. Novus works better for deeper scratches and scrapes.

Walk through almost any marina and you’ll see that many of the boats—maybe even a majority—have clouded, muddied or scratched up windscreens, windows and porthole lenses. In some cases, vision may be so obscured that it threatens the safe operation of the boat.

Most of us blame the sun and marine environment for the natural damage and degradation they cause in plastics. In fact, in some cases, boat- owners themselves are at fault. With proper maintenance, clear plastics can stay that way for years. Use of the wrong cleaning products and methods, however, can put them out of commission in a season. Choosing the right product involves knowing what your plastic is made of.

We found no more than 10 products on the market expressly made for clear plastic cleaning, restoration and polish. We tested them on some standard marine plastics to see which ones you should include as part of your boat maintenance kit.

A Plastics Glossary
There are three basic types of transparent plastics used on boats: clear vinyls, acrylics (the best known is Plexiglas), and polycarbonates (the marine standard is Lexan). Each has advantages and disadvantages, which is why most boats include some of each.

Vinyl is actually plasticized, stabilized polyvinyl chloride (PVC). It’s the plastic of choice for any window or clear screen that rolls, folds, stretches or needs to be sewn to fabrics. It is used most commonly in roll-up windscreens and windows because of these properties. It doesn’t have the clarity of glass, can distort vision, and will ripple in high heat.

Clear vinyl is the most unstable plastic commonly found on a boat. It has three distinct modes of failure: UV degradation from sunlight, which will cause it to become cloudy, muddy, and opaque; loss of plasticizer, which will cause it to become brittle; and mechanical scratching. A cleaner/protectant can help reduce plasticizer evaporation by coating the surface of the vinyl and can prevent scratching by keeping grit and salt from reaching the surface. Halting UV degradation is harder, but vinyl has blockers built-in, and a protective coating will help them do their job. Once vinyl degrades significantly, there’s not much you can do about it.

Vinyl pits, scratches and cuts easily. It’s soft and extremely vulnerable to grit and salt crystals. In fact, one of the worst things you can do at the end of the season is to roll up your vinyl without cleaning and polishing it first. You’re likely to find it’s a scratched-up mess when you roll it out next year. Heavier gauges are especially prone to scratching. Heavily scratched vinyl is often beyond repair.

An abrasive scratch remover or polish will destroy the surface of vinyl. Use a soft cloth to clean it and a polish to protect it. Avoid citrus oil-based cleaners and also the relatively rare ones with alcohol in them. They’ll dissolve plasticizers, damaging the vinyl. Well-maintained clear vinyl can last five years and longer.

Acrylics and polycarbonates are varieties of hard plastics commonly used on porthole lenses, windscreens, and instrument covers. These plastics cost at least twice that of vinyl. Thick sheets can be ultra-hard, with enormous tensile strength and tremendous clarity, even better than glass. Moreover, polycarbonates have 100 times the impact resistance of glass, but weigh less than half. These properties make polycarbonates a good alternate choice for eyeglasses and airplane windshields. Don’t test it, but a half-inch-thick piece of Lexan should stop a bullet. Lexan is virtually shatterproof, while Plexiglas® acrylic will shatter. These plastics are far more resistant to UV degradation than vinyl.

Curiously, as hard as they are, their surfaces have pores that make them prone to catching and holding dirt, which can build up quickly. Polishes fill the pores, giving the surfaces a protective coating. When left unprotected, however, windscreens and porthole lenses can quickly become covered with an irritating network of tiny scratches. (A clear water rinse is wise after every outing.)

All too often, however, these scratches are actually the result of well-intentioned cleaning. A paper towel is just about the worst thing you can use for the task. Believe it or not, bulletproof plastic will scratch with a paper towel. Even worse than paper towels would be a hard brush or squeegee. Sponges often collect grit that can scratch. Use a clean, old cotton T-shirt or terry cloth. Throw them out or wash them afterwards because they can gather grit that will scratch the next surface you clean.

Ammonia, alcohol and solvents are destructive to Plexiglas. Don’t simply use your favorite household cleaner, especially on Plexiglas. (However, GE Plastics, which makes Lexan, recommends Formula 409 for simple clean-ups.)

Also, be very careful with any restoring compound you use. Some that we tested, like Mirror Glaze 17 Clear Plastic Cleaner, have more grit for scratch removal than you’d expect. Test any polish you’re using on a small, unobtrusive section first. In removing scratches, work the scratch remover in at a right angle to the scratches.

What We Tested
We found nine cleaners and restorers formulated for most boat plastics. Some are all-in-one products: Beckson Plasti-care Cleaner, Meguiar’s Mirror Glaze 18 Clear Plastic Cleaner/Polish, Mer-maids Plexiglas/Plastic Cleaner & Polish, Plexus Plastic Cleaner Protectant & Polish, and West Marine One Step Plastic Cleaner Polish.

Others are two- or three-step kits: Mirror Glaze 17 Clear Plastic Cleaner and 10 Clear Plastic Polish, Top Choice Clear Plastic Cleaner and Clear Plastic Scratch Remover, Novus 1 Plastic Clean & Shine, 2 Fine Scratch Remover, and 3 Heavy Scratch Remover.

We also tested a non-ammonia-based, all-purpose cleaner that includes clear plastics among its uses—Glass Plus. (Don’t bother. Something that is formulated for glass, but doesn’t contain strong cleaners, won’t do much at all to sea grime.)

3M offers Acrylic and Polycarbonate Plastic Reconditioning Systems. They’re designed for extensive repair work with machines using their buff and polish pads. They’re packaged for the professional, so we didn’t include them in our tests. (Mirror Glaze is also sold in professional-grade packages for use with machinery.)

How We Tested
The good folks at Bomar, a Charleston, NH, manufacturer of windscreens and porthole lens, provided us with some old pieces of tinted Lexan and Plexiglas. Venerable sailmaker Hathaway, Reiser & Raymond of Stamford, Connecticut, gave us some old pieces of vinyl that had gone into sail windows. All of our surfaces were scratched and scraped, with both deep and fine cuts, and grimy. None of the pieces had suffered serious UV degradation. We rinsed them with water and used a soft-cloth to dry them. We then applied the cleaners and polishes according to their instructions.

What We Found
While all of the products do an acceptable job, several have drawbacks; two—Novus and Plexus—were outstanding.

Beckson Plasti-care Clear Plastic Cleaner. Beckson makes and distributes a wide variety of marine hardware. The cleaner is designed to maintain its line of ports and windows. It isn’t a polish or scratch remover, but is a petroleum distillate that claims to contain protectants. It comes in an easy-to-use bottle. It did a fine job on vinyl, but only fair on both the acrylic and polycarbonates, for which it is expressly intended. It seems to be heavily diluted. You can do better. Size: 8 ounces. Price: $5.25.

Mer-maids Plexiglas/Plastic Cleaner & Polish. This product comes in a pump container that mists nicely. It did only a fair job at cleaning up the surface of all our plastic test materials and was poor at filling scratches. There was little apparent difference after using it. One factor that may make it inappropriate for the closed interiors of boats is that it gave the testers a terrific headache. Some of the other oil-based products had much less strong odors. It comes with a series of scary labels, including warnings about wearing eye protection and avoiding dangerously slippery overspill. Perhaps the others should include such warnings about potential hazards, but most other formulations are less likely to run. Not recommended. Size: 16 ounces. Price: $7.66

Meguiar’s Mirror Glaze 10 Clear Plastic Polish, 17 Clear Plastic Cleaner, 18 Clear Plastic Cleaner/Polish. We tried out the all-in-one number 18, which comes in a convenient pump container, but found it was just fair at basic cleaning and really wasn’t very good for polishing away fine scratches. The 17 and 10 are designed to be used in combination to remove fine scratches and then polish up the plastic. Both are pourable pastes in squeeze containers. Our experience was that the combination didn’t do the job. The scratch removal grit in 17 was too abrasive for vinyl and could cause more harm than good. It is more appropriate on acrylics and polycarbonates, especially on the Lexan. If you’re looking for an easy-to-use and safe kit, it’s not the way we’d go. All come in 8-ounce containers. Prices: 10, $5.75; 17, $5.75; 18, $6.49.

Novus Plastic Clean & Shine, Polish No. 1, Fine Scratch Remover, Polish No. 2, Heavy Scratch Remover, Polish No. 3. Among the multi-step kits, this is our pick. The three grades make it easier to avoid missteps that mar surfaces. The No. 1, which comes in a pump container, cleaned up the plastics well and is good for maintenance, but really had no scratch removal benefits. However, in conjunction with its other two (pourable pastes), Novus did the best job handling extensive scratches. The smell wasn’t sweet but wasn’t brain melting either. For plastics that have weathered some, this is the way we’d go. Size: 8-ounce containers. Price: No. 1: $4; 2: $5; 3: $6.

Plexus Plastic Cleaner Protectant & Polish. Plexus was unique among our test products in coming in an aerosol spray can. It was also uniquely effective for ease-of-use, cleaning and filling in fine scratches on all the plastic test surfaces. Originally developed for use on aircraft, Plexus has almost universal clear plastic applications. It sprays on and cleans up remarkably easily. And it actually smells pretty fresh. More significantly, it fills pores and fine scratches and leaves a non-static, non-filmy protective coating. If you’ve got clear plastic that’s still in good shape, get Plexus for your regular maintenance and end-of-the-season clean-up. Size: 13-ounce spray can. Price: $7.95.

Star-brite Plastic Scratch Remover, Plastic Polish/Restorer. This two-step kit does a very workmanlike job. The scratch remover come in an easy- to-pour bottle. It’s a bit less aggressive than the Mirror Glaze 17, making it a better choice for lightly scratched plastics. Although the people at Bomar found Star-brite worked best in their tests, we didn’t think it did a great job on cleanup and restoring optical clarity. Also, the smell is pretty strong. Still, they’re both very acceptable products. Both come in 8-ounce containers. Price: $6.45 for each.

Top Choice Clear Plastic Cleaning Kit. Top Choice comes as a two-part kit, shrink wrapped together. The Clear Plastic Cleaner comes in a pump container. The Clear Plastic Scratch Remover is a pourable paste. The scratch remover is less aggressive than others and, in combination with the cleaner worked well on lightly scratched surfaces, especially the Plexiglas.

The cleaner has excellent protective qualities. At $10.98 for the two 8-ounce containers together, it’s a good price. You won’t go wrong with it, but we felt the flexibility of the Novus 3-part kit was more attractive.

West Marine One Step Plastic Cleaner Polish. There’s a reason that all the other plastic cleaners and polishes contain petroleum distillates: They work better. This water-based product won’t rot your brain with fumes, but it won’t clean up or polish your plastics as well either. In fairness, it did do an acceptable clean-up job, especially on acrylic, but had no scratch-filling or removing properties that we could see. It runs $4.99 for an 8-ounce pump container.


Contacts- Beckson Marine, Inc., 116 Holland Avenue, Bridgeport, CT 06605; 203/333-1412. Mer-maids Distributing Company, Edmonds, WA 98020. Meguiar’s, Inc., P.O. Box 17177, Irvine, CA 92713; 800/347-5700. Novus, 10425 Hampshire Ave. So., Minneapolis, MN 55438; 612-944-8000. Plexus, B.T.I. Chemical Company, 638 Lindero Canyon Rd., Agoura, CA 01301; 818/879-1493. Star-brite, 4041 S.W. 47 Avenue, Ft. Lauderdale, FL 33314; 800/327-8583. Top Choice Industries, P.O. Box 279, Rheems, PA 17570; 717/367-2008. West Marine, P.O. Box 50050, Watsonville, CA 95077; 800/538-0775.

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