Tips for
 Painting Fiberglass Boats

by David Pascoe, Marine Surveyor

One of the most frequent questions that a marine surveyor is asked is whether it is worthwhile to paint a fiberglass boat. The answer is a qualified yes, so long as the owner fully understands the extent of the work and cost involved. Fortunately, there are some very clear advantages in doing so.

Introduction

Most boats still use gelcoat for the exterior finish. Gelcoat is basically a resin with very high pigmentation content that gives it its color. But gelcoat is used for another reason, and that is as a mold release agent that helps prevent the fiberglass part from bonding to the mold at the time it is laid up. Unfortunately, most gel coats have relatively poor resistance to sunlight and other environmental factors, despite claims to the contrary. Thus, we see the apparently never ending problem of boat finishes fading and chalking after only a few years time.

There are very high quality gel coats available that can hold up over the years, but very few builders use them because they are quite expensive. Bertram, for example, has always used a top quality gelcoat that, even after decades of aging, could be successfully buffed out and polished. But if you wax your boat and only a few months later it turns dull again, you've got a low quality gelcoat that won't hold a finish.

For boats using average or poor quality gel coats that begin to oxidize and chalk early on, painting is the only practical solution. Unfortunately, painting is expensive, but when done properly it results in a finish that can last for a decade or more. In fact, with only annual cleaning and waxing, urethane finishes have been know to last for 15 years or more, even under the harsh Florida sun. Before making a decision, here are some important factors that you should consider.

Selecting a Painter

Whether you use a yard or a jobber, beware that the price should not be the only factor in choosing a painter. The lowest cost will usually translate to the lowest quality of work. Jobbers tend to come and go with frequency because painting boats is a rough and difficult business. The ones who do the best work are usually more than happy to give you references of prior customers. It will be more than worth your while to investigate and actually go look at examples of their work.

As a rule, yards generally do higher quality work because they have a reputation to maintain. But it will cost more because they have higher overhead, and because they're probably paying higher labor rates. On the other hand, jobbers tend to be rather transient and their work can be inconsistent and unreliable. Be sure that they have a good track record and that they're likely to be around for while longer should they fail to perform to your satisfaction. If you're going to use a jobber, you'd be wise to get them to post a performance bond.

Not only are sprayers of urethane paints required by law to have an enclosed spray booth for environmental considerations, but it is not possible to achieve a good result when spraying in the open atmosphere. Be wary of any painter that does not have a covered paint shed.

Dark Colors

A current trend is to use dark colors, especially black, to change the appearance, such as painting the space between windows black, or wide feature stripes. Because dark colors absorb much more heat, paint large areas in dark colors can result in damage or distortion to surfaces being painted. Remember that fiberglass boats are plastic and somewhat heat sensitive. Because these plastics are thermosetting, a dark surface heats up under the sun and then the plastic continues to cure. This often results in shrinkage that can serious distort the surface, resulting in permanent damage. The most serious damage occurs with cored laminates, particularly foam. You may have noticed some boats have a checkerboard pattern within these painted surfaces. This is caused by a secondary cure resulting from painting a cored laminate black that leads to shrinkage and the core showing through.

Preparation

The three most important factors in getting a good result are preparation, preparation, preparation. Seventy-five percent of the cost of painting involves preparation. Any paint job is only as good as the preparation that precedes it, and the skill of the people doing the work. Improper preparation can only result in dissatisfaction and a failed paint job.

Old gel coats are often porous and have absorbed years worth of waxes and oils, a condition that reduces the ability of new paint to adhere to the surface. Thorough dew axing and sanding is needed to make sure that contaminates are removed. This is followed by special primer coats that improve adhesive properties. All surface irregularities must be smoothed out, old holes and scratches filled and carefully faired out. There's nothing like a fresh, glossy coat of new paint to show up surface defects. Unless this work is carefully accomplished, all existing surface defects will be magnified and you will not be happy with the result.

Before signing a work order, you should go over the entire boat with the painter. Review all of the areas that need repair or special work. Have the painter tell you what needs to be done to achieve the best possible job, then decide if you're willing to foot the bill. Don't leave it up to the painter to make your decisions for you. Make it a point to ask about potential problems.

Removing Hardware

If you've ever seen a boat that was painted by masking around hardware and painting over widow frames and other plastic parts, you know what a bad paint job looks like. To achieve the best result, every possible piece of hardware should be removed. Yes, this is time-consuming and costly, but a good quality result cannot be had without doing so.

When hardware and other fastened on parts are masked, this usually results in the paint bridging between the part and the mounting surface. The paint will eventually crack at this point, and when it does, water will then begin to migrate under the paint, resulting in flaking and peeling. This is true for virtually any kind of part mounted on the boat. That's why it's always best to remove the part if at all possible.

Aluminum window frames and sliding doors should not be painted over for several reasons. First, because most frames are anodized and paint will not adhere well. Second, because the frames have stainless steel screws in them, the dissimilar metals cause galvanic corrosion. This is why we see so many painted window frames with blistering and peeling paint. If the frames are anodized, don't paint them. Instead, the frames should be removed before painting. If the frames are in poor condition, they should be removed, stripped, sanded and repainted separately.

Plastic Parts

should also be removed before painting, even if you are going to paint the plastic parts. The reason is that painting over the stainless screws will only result in corrosion and flaking.

Painting over caulked joints results in an unsightly mess. Caulking is soft and the paint is hard therefore the paint will crack and begin flaking away wherever it is laid over caulking. For this reason, all caulking must be stripped off prior to painting, and recaulked afterwards.

Teak Trim

All teak trim such as hand railings and covering boards must be removed before painting. The reason is that wood holds moisture that will eventually migrate under the paint and result in peeling. The entire area under the wood should be completely prepped and painted.

Difficult Areas

Small, confined or enclosed areas such as up under eyebrows or tight spaces on flying bridges or cockpits are often not amenable to spray painting. The result is often heavy orange peel or unsightly over spray. There are several alternatives to this problem, the first being not to paint the area if it is not really necessary. Carefully consider how it will look if you don't paint it. Another is to inquire if the painter has a skilled brush painter that can use a brush. Although some brush marks will be visible, really good brush painters can do a better job than a sprayer in these tight quarters.

Non Skid Decks

Decks that have a molded in non skid surface do not take well to painting. Not only can't the surface be sanded, but the high points of the texture will wear the paint away more rapidly and likely leave the surface looking more unsightly than it was before. Carefully consider whether high profile non skid surfaces should be painted. You may want to just paint around them. On the other hand, smooth decks with abrasive material added to the paint works well. Less, rather than more texture is best.

When to Paint

To achieve the best results, boats should be painted when the temperature is between 70 - 80oF and the humidity below 65%. In the north, the window of opportunity is rather short unless the painter has an indoor facility. To get the best price, consider doing the job toward the end of the season rather than at the beginning.

In the south, particularly Florida, avoid the rainy season, mid-May to early June and late August through October. Frequent rains can not only ruin a paint job, but the frequent weather interruptions cause the job to take longer because of frequent delays. In Florida, the prime painting season is late November through April when there is little rain and low humidity. The peak painting season is January to June, so you'll likely get better prices in the summer and fall, although you risk getting lower quality. For bargains, look for a painter with inside facility and schedule for late summer and fall.

Making a Work Order

The objective of creating a good contract or work order is that both parties should know what they're agreeing to. Foremost is the nature of preparation to be done and a definition of the final result. We all know the difference between the $129.95 auto paint job and a good one that costs a thousand dollars. With yachts, its not quite that clear cut, but the end results are much the same. Remember that if you've driven a hard bargain for a price, but are not happy with the results, you won't have a leg to stand on if you haven't specified the quality of work to be done.

1. Take the time to specify the exact nature of all the preparation work to be done.
2. Specify the primers and finish coats to be used.
3. Specify the nature of the defects that you will or will not accept. These include fish eyes (caused by contamination), dust in finish, runs and sags, over spray and orange peel. Remember that the later are inevitable in all but the highest (and most expensive) quality of work.
4. Don't expect a warranty if you paint over aluminum hardware and trim.
5. Don't pay the full price up front. Pay half down in advance and half upon completion to your satisfaction.

Proper Care

A good paint job should last for ten years or longer with proper care:

• Don't use harsh detergents or abrasive cleansers for cleaning. Use only a very soft, natural bristle brush or mop. Never use plastic or stiff brushes that will scratch the paint. If you must use an abrasive such as on non skid, remember that chlorinated cleansers will damage the paint if allowed to remain in contact for more than a few minutes. Be sure to rinse thoroughly, especially the point where the water runs down the hull side.
  
• Keep the boat clean. Accumulated dirt and atmospheric fallout can result in acids forming on the surface of the paint and damaging it.
  
• Wash down thoroughly to remove all salt after using, including the hull sides.
  
• Wax the boat at least once per year, except for walking surfaces, or course.
  
• Avoid ice damage cover the boat during winter lay up.

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