The Care and Feeding of Your Clear Vinyl Boat Windows

By: James "Doc" Lewis

Strataglass?, Lexan?, Plexiglass?, Isenglass, Crystal Clear, Eisenglass, etc. Whatever you call it, it all comes from polyvinyl chloride (PVC) which has certain definite characteristics.

1. Vinyl is a UV-sensitive material which degrades when exposed to sunlight.

2. A vinyl's topcoat holds in plasticizers, softening agents which keep vinyl supple.

3. Clear vinyl has NO topcoat. (The one exception to this rule is Strataglass, which has a protective coating. Unless otherwise noted, the advise in this article applies only to untreated clear vinyl and therefore excludes Strataglass.)

That's It! All you ever needed to know about vinyl boat windows in one easy lesson. Maintaining a topcoat and protecting against UV damage will keep vinyl looking good for years.

Let up, for as little as a month, in this climate, and, well, read on . . .

The sad truth is that all of those lovely, clear, vinyl windows, that you were so proud of when they were new, will yellow, scratch, and become an ugly nuisance in a very short time without proper care.

Q. What you mean Doc, you don't just hang um and forget um?

Who is that guy?

Unlike regular safety glass which has a fairly hard surface and resists scratching, and even your vinyl seats which have a top-coat to protect the underlying material, a vinyl window requires a protective coating to separate it from the elements.

Think of it a little like your skin. With regular washing, sunscreen, and moisturizer our skin can take the Emerald Coast summer conditions without too much trouble. Eliminate one or more of these and stay outside 24/7 and we'll be looking 102 years old in no time, even if we're only 20.

Cleaning Procedure

At BoatDocs1 we start off by removing as much of the loose dirt as possible with a fine water spray. It's best to wet the entire surface giving the water time to soften anything stuck to the window. Next we gently wash the surface with a mild soap and water solution. (No detergents or harsh cleansers, PLEASE)

Next, give the window a thorough rinsing with more fresh water and then dry, either with a clean terry cloth towel or chamois.

After several years of experimentation and research we have been convinced beyond a doubt that the only product to use on vinyl is 303Products, Aerospace Protectant. I'll let you go to their web site and read their copy on why it's the best. But notice I said copy, not hype, because after using it for over a year I find their advertising to actually be a little understated.

We treat by spraying the product on both sides of the surface and then polishing with a clean, dry, and well worn terry cloth towel. Old baby diapers are better but are becoming nearly as rare as DoDo eggs. . Applications last from 4-6 weeks and after the first couple of uses it seems to get easier to maintain as the surface actually seals itself and nothing seems to stick to it.

Application improves visibility and reduces wear and scratching by reducing the coefficient of friction. In laymens terms this just means that it makes the surface slicker than snail snot. It also repels water, dust, dirt, salt, and ultra-violet radiation. (SPF 40) Added benefits are an anti-fog/anti-glare finish.

A monthly treatment will keep those curtains looking like new for many years.

And What About Strataglass??

At the beginning of this article I mentioned that Strataglass doesn't fit the general recommendations for regular untreated vinyl windows.

The reason behind this is that it is treated, at the factory, with a special protective coating which if maintained in accordance with their recommendations will last the life of the fabric and prevent the chemical leaching which is the cause of problems for the untreated fabrics.

I don't want to get too far into specifics with this as they do have a website of their own and have care and cleaning advise which they offer their customers. If you have Strataglass? curtains on your boat I suggest going to their website at and seeing just what they suggest for their product.

What if we're too late?

If your vinyl windows have begun to show the effects of aging, we apologize.(should have told you sooner) We offer a restoration service consisting of fine polishing and a chemical treatment. (replacement of the plasticizers) In many cases we can eliminate most scratches, restore the translucent properties, and with continued maintenance with 303 Aerospace Protectant will add years to the effective life of your vinyl windows.

If you have some vinyl windows which you are thinking about replacing let us take a look and see what we can do. The service is quite reasonable when compared to the price of replacement.

Below is the step by step procedure we follow to bring back vinyl windows - hope it helps.


This set of instructions is for windows with moderate scratching and crazing. If the scratches are very deep the process would need to be started off with wet sanding which is a subject all by itself and won't be covered in this article.

What we want to accomplish here is to polish out any scratches, stains, imperfections, or swirl marks starting with a very fine compound and then finishing with a restorer polish to replenish the plasticizers in the vinyl.


You should find all of these items at an automotive paint store. To start with you will need a variable speed electric drill (1000-1200 rpm) with a velcro backing plate which will accept foam rubber polishing pads. You will need 3 of the pads but an extra one will save some time when changing polish. Always reserve a pad for each compound or polish. While your there ask if they carry the fine, micro-polishing compounds made specifically for clear vinyl windows that you will use to actually remove the scratches. If the sales-person seems to know what they're talking about, pick his brain on what products he sells the most of for this purpose.

I have had excellent results with a 3-M product called "Finesse-it", which is used on both gelcoat and vinyl to good effect. If your trip to the automotive supply doesn't turn up anything better this will do the job and you can use what's left over on the rest of your boat.

Another product I recommend highly, is Meguiars, "Plastx" which is perfect for the finish (polish) runs with the pads. It also makes a good occasional cleaner and preservative throughout the year. It uses the Microscopic Diminishing Abrasive Technology, (MDAT), used in their paint and gelcoat polishes to produce a powerful, yet safe plastic cleaner. If the scratches are light you may get good results by using just this product and making a couple of passes with the buffer.


If you have some experience with polishing it's a plus although the technique used here is unique to the material and therefore will be learned as you go along.

We usually start with the smallest, or least noticeable window first to get an idea of the amount of work needed and to check the results. If there are several small pieces choose the one which is most damaged. After completing one is a good time to compare the work involved with the expense of replacing the window. If time isn't a prime consideration but money is, then this system will serve you well.

Step by Step:


First thing is to thoroughly wash the window using a mild (Ivory is good) soap and water solution, rinsing well, and then drying gently with a soft cotton towel. I prefer old cloth diapers when I can get them but they have become nearly extinct in my neck of the woods. The main thing is to always use the softest, cleanest towel you can find on your windows and now is a good time to start.


After the window is dry lay it out on a firm, flat table with plenty of soft padding underneath. Make sure the padding is smooth and level or you'll leave edges as you polish. Set up your drill with the backing plate and the first pad and apply enough of the polish to the window to cover a 1 foot square section.

Immediately start buffing the section using light pressure and keeping the pad moving. The secret here is slow and easy, it's plastic not concrete. Keep it moist (use a water spray bottle) and when the compound is nearly used up, you'll get a feel for it, reapply to an adjoining section and repeat the procedure. Continue till the side has been done and then gently clean using the procedure outlined above for cleaning.


When the polishing and cleaning is completed (both sides) take a clean pad and apply the Plastx to the entire window following the same procedure as for the compound/polish. When the window has been completely covered take a clean cotton cloth and buff off the haze. The vinyl will absorb most of the Plastx which will help feed and restore the plasticizers.

As a final procedure I usually go over the entire window with 303 Products Space Age Protectant to assure protection from ultra violet radiation, the number 1 enemy of all vinyl and clear vinyl windows particularly.

A Couple of Tips on Vinyl:

NEVER use any kind of regular window cleaners, detergents, abrasives, petroleum based products, or alcohol on vinyl windows. They are too harsh and will damage the top coat, speeding up the loss of plasticizers. The vinyl will dry out, turn yellow and brittle, and soon need to be replaced. You've seen this before, now you know why.

Right along with this is a big ditto for all of your vinyl products either on the boat or ashore. Only the mildest soap solution, complete rinsing and a safe protective coating will keep all of your vinyl goods looking like new.

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