Key Facts about Protecting Your Boat’s T-Top
Nearly every boat has some amount of metal on board. It might not be much–bow rails and cleats, or maybe a Bimini top frame. Other boats have a massive amount of metal in the form of T-tops, tuna towers, poling platforms, rod holders, and rails of every description. All of this can look beautiful, but it’s important to remember that salt water is an acid. If left on even the sturdiest of metals, corrosion will eventually result.
Powder coating is a great way to extend the life of your T-top and maintain its good looks for decades. For a good result, you need to remove all rust and properly clean the metal surfaces before powder coating them. You also need to maintain your T-top by washing and rinsing with soap and water every time you use your boat.
So how can you protect all those valuable components that add so much to your boating experience? There are several ways to protect the metal from the elements, and the type of metal you have onboard is going to determine what options are available to you.
Never forget the power of saltwater. It forms the shorelines of the earth and can wash away islands or pile up sandbars. And on your boat, only a little bit is needed to cause trouble.
Types of Corrosion
Metal components will corrode, no matter what they are made of. Simple corrosion is the term for the process by which molecules on the surface of a piece of metal will combine with oxygen to make a metal oxide, a process known as oxidization. This is why metal rusts and aluminum corrodes.
Galvanic corrosion is a bigger problem. Galvanic corrosion occurs when two metals are connected together in a common electrolyte. The electrolyte in our case is water, specifically salt water. And if you have any aluminum components on your boat, chances are they attach with stainless bolts. The result is a simple battery, where the more noble metal (the stainless) steals electrons from the less noble (the aluminum). This type of corrosion is commonly referred to as dissimilar metal corrosion.
This is the same reason that sacrificial anodes are used to protect the underwater metals on your boat. One of the least noble metals, zinc or a weak aluminum in most cases, is attached below the waterline. Since galvanic corrosion attacks the least noble metals first, the anode corrodes while protecting your heavier aluminum outboards, bronze through-hulls, and stainless or bronze propellers. Once that anode is gone, however, your aluminum outboard is in real trouble.
Crevice corrosion is another problem area for deck hardware. Stainless steel maintains its resistance to corrosion only if there is plenty of oxygen present. If a stainless fastener is used, and some water gets near it, it will begin to corrode. Where bolts connect to the deck or other fixtures, sealants should be used to keep moisture out.
Tips for Preventing Corrosion
When left to its own devices, a metal part on a boat will start corroding quickly. This is especially true of ferrous metals that rust and unprotected aluminum that will corrode. Quality stainless steel components will last for years, but more and more low-quality stainless is on the market. Polished stainless is easy to take care of, but what about aluminum and other components?
Understanding where corrosion comes from and where to keep an eye out is important, but what matters to boat owners is knowing how to prevent it. Keeping your hardware clean and dry makes a big difference. Frequent freshwater rinses keep the saltwater off. Ideally, you’d want to rinse off the boat every day it’s near saltwater.
But it’s also important to note that corrosion doesn’t just result from saltwater. One of the most common types on boats comes from dissimilar metals. Your aluminum T-top is held on with stainless fasteners. Where the stainless touches the aluminum, corrosion will result. The next time you’re at the boatyard, take a look at the fasteners on your neighbor’s T-top. Chances are you will see at least some corrosion around the bolts. You can help prevent dissimilar metal corrosion in fasteners by using chemicals like Tef-Gel or Lanicote.
T-Top Construction and Covering Options
Metal components on boats, whether T-tops, poling platforms on skiffs, or tuna towers on offshore boats, are usually made of either aluminum or stainless steel. Aluminum is cheaper, but because it is less sturdy than stainless it must be made with thicker tubing. Stainless is the hardier choice and is more resistant to corrosion. Either way, the metal must be protected from the harsh elements that it’s exposed to in the boating environment.
Stainless is usually polished to a bright and shiny finish to protect it. This is easy to maintain and easy to clean. With a quick rinse, it can last years. If you do get any corrosion or surface rust on stainless, it is usually quickly and easily tended to with one of the many widely available stainless cleaners.
Aluminum components are a bit more problematic. Some form of permanent protection is needed to ward off the corrosion and to keep your boat looking good. Aluminum can be anodized or painted. Unfortunately, paint will not stick very well to metal and chips easily. Nearly all new aluminum components are anodized, but once that begins to wear off something else needs to be found.
Powder coating is a great option. It has the look of painted parts, but it is much harder and takes a bit more abuse. But like all components on your boat, maintenance and upkeep are important if you want to keep it looking good for years to come.
If you bought your aluminum hardware new, it was more than likely anodized.
Protective coatings on metal come in two forms. Powder coat and paint are considered organic coatings. In these processes, a chemical adheres to the metal component. Anodizing, like plating or galvanizing, is an electrochemical process. With anodized aluminum, the exterior layer of metal is converted to aluminum oxide. It’s actually part of the surface, not just another product adhered to the surface.
Anodized aluminum looks like polished aluminum, except it has a deep clear-coated look to it. Anodizing is a clear finish that looks especially good on aluminum since it deepens the color a bit.
Properly anodized aluminum can last decades. There are many advantages to anodizing over organic coatings. For one, anodization is UV resistant. And since anodizing is an integral part of the metal, you don’t have to worry about it flaking off.
The cons of anodizing are price and availability. When it comes to your T-top frame, it might be a challenge to find someone who can anodize it in your area. More than likely, anodizing would be a choice when you order a new top, but not when you are looking to have it refinished.
The two biggest enemies of anodized aluminum are corrosion and scratches. Simple corrosion would not likely be a problem, but galvanic corrosion from stainless fasteners is a big problem. Once the anodizing begins to fail, the metal will have to be cleaned thoroughly with sandblasting and acid washing. Then a new protective layer will have to be applied. With proper prep, any coating can be used on top of anodized aluminum. The most popular option is powder coating.
What is Powder Coating?
Powder coating is basically a painting process, but the paint comes in a powder form instead of a liquid. It is sprayed onto the metal and held in place via electrostatic charge. The piece is then heated up, and the powder coating molecules bond to one another. This forms a solid layer of material on the metal object that is much thicker and harder than liquid paints.
Just like paint, powder coating can be done in pretty much any color you like. The most common colors are black and white, and they can be done in either a matte or glossy finish.
Maintaining Powder Coating
Taking care of your powder coating is a matter of keeping it clean and free from nicks and scratches. Any and all corrosion issues must be taken care of immediately. Make sure to rinse it off after every run in saltwater.
The primary concern with powder coating that is that, should the metal underneath corrode, the coating will lose contact with the metal. Should this happen, the powder coating will become brittle, crack, and finally flake off. Once this process has begun, the flaking spreads like cancer as more and more grime and corrosion get underneath the coating.
If you want your powder coating to last as long as possible, then any corrosion or bubbling must be treated as soon as it is noticed. Scrap and clean the flaking powder coat and remove all corrosion. Wipe down the metal with acetone, and then paint the area to seal it in.
How Long Does it Last
The lifespan of your powder coated metalwork depends on how well it was applied and on your maintenance regimen. It’s not uncommon for powder coated items to still look great after 10 or 15 years. If the underlying metal is kept free of the corrosion issues that make powder coating bubble up and flake off, there’s no reason it can’t last indefinitely.
But keeping corrosion entirely off of a boat is hard work. If you store your boat in the water or if you have limited access to freshwater rinses, you might find keeping on top of corrosion issues to be a bit tiring.
Can Stainless be Powder Coated?
Stainless steel components can be powder coated too. Just like aluminum, they must be prepped properly. This will include sandblasting and chemical washing.
But the real question is, why would you want to? Most quality stainless components are resistant to corrosion in the marine environment already. When a bit of rust or corrosion does appear, it’s easily tended to and cleaned off.
If your stainless is in rough shape, you could more likely benefit from a heavy-duty cleaner and polisher. It’s a lot of work, but chances are it will restore better and last longer than powder coating of stainless.
Cost and Application
The cost of a powder coat job varies widely depending on the size of the piece and how much prep work is involved. If you are doing your T-top or tower, and you can remove it from the boat yourself and get it to the powder coater, you’re sure to save a bundle.
Many types of facilities do powder coating, and it’s important to remember that powder coating is used in many industries other than boat parts. If you shop around, you will probably be able to find an industrial powder coat professional who can do your job for you. This might save a few bucks when compared to marine service providers.
It’s also worth mentioning that before a powder coat job, you may need to have the metal cleaned and perhaps even sandblasted. The more prep work that is involved, the more the job will cost. But don’t be tempted to skimp. If any amount of corrosion is left on the metal, your new powder coating will begin flaking off in short order.
The quality of a powder coat job varies significantly from one applicator to another. There are many many factors at play, so it can be really difficult to nail down who does the best job for the best price in your area. Two main factors generally contribute to low-quality jobs, however.
Like any paint job, the overall quality of the final product is a factor of prep work. How clean is the metal before powder coating? Has every single spec of corrosion been taken care of? Have the right primers been used to ensure that the powder coating will adhere as well as it should?
The second factor is the thickness of the powder coating. In an effort to save money, some applicators may apply the powder too thin. Thin coats are more likely to chip or flake, meaning they won’t last as long.
You should also know that there are other alternatives.
While you may be tempted to paint or clear coat your T-top yourself, it’s generally not advised. It’s impossible to get the paint to adhere well enough to the metal parts for it to have a reasonable service life. If you want to try painting metals, consider having the components sandblasted before you apply the paint. This will rough up the metal and give enough tooth for the paint to stick. Two-part paints are the hardiest options that can stand up to the abuses of boat life.
Line-X is a new product that has become very popular for boat tops. The company is known for making a super-tough truck bed liner coating. But, because this durable spray-on coating is easy to apply and hardy, the coating is used for all sorts of other purposes. You’ll have to find a Line-X provider in your area, and it’s probably the most expensive option, but it’s sturdy and looks great.
Powder coating is becoming more and more popular as a coating for old aluminum towers and T-tops. Some like the look and the color options that coordinate with the rest of their boat. Others just want a rugged surface that will stand up to the elements. Either way, your success with powder coating depends entirely on how clean you keep it and how quickly corrosion issues are taken care of.