Saw some questions on bottom paints and though this may help, was from a local dealer up my way.
ANTIFOULING PAINTS 101
By Dan Tholen ? Lacey Marine
Different Types of Antifouling Paints
? HARD ANTIFOULINGS ? The technical term for these types of antifouling paints is ?contact leaching?. The paint dries to a porous film that is packed with biocides, which leach out on contact with water to prevent fouling growth. This leaching is chemically designed to release biocide throughout the season, but the amount will steadily decrease until there is not enough biocide coming out of the paint film to maintain fouling protection. Once the biocide is exhausted, the hard paint film remains on the boat. Hard antifoulings do not retain their antifouling ability out of the water and cannot be hauled and relaunched without repainting. One of the main benefits of this type of antifouling is its resistance to abrasion and rubbing. This makes it ideal for fast powerboats, racing sailboats or boats where the owners have the bottoms scrubbed regularly. Most hard antifouling paints can be wet sanded and burnished prior to launch to reduce drag and improve hull speed. Types of paints: Interlux Bottomkote, Interlux Nautical Epoxycop, Pettit Unepoxy.
? ABLATIVE ANTIFOULINGS ? Ablative antifoulings wear away with use like the controlled depletion polymers but at a much less controlled rate. Ablative antifoulings are affected more by water temperature, salinity and alkalinity than are the controlled depletion polymers and generally wear away faster. They are less expensive than controlled depletion polymers and they provide excellent antifouling protection but they don?t last as long as the Controlled Depletion Polymers Or Controlled Solubility Copolymers. Types of paints: Interlux ACT, Aquagard Bottompaint.
? CONTROLLED SOLUBILITY COPOLYMERS ? These types of antifoulings are partially soluble which means that as water passes across the surface of the coating, it wears down much like a bar of soap would wear away. The physical action of the water over the surface steadily reduces the thickness of the paint at a controlled rate, which results in always having fresh biocide at the surface of the paint throughout the season. For this reason these types of antifoulings have the capability to perform in the areas of highest fouling challenge. Boats painted with Controlled Solubility Copolymers can be hauled and relaunched without repainting since the biocides are chemically bound to the paint film and are only active when in the water. The longevity of these coatings is related to the thickness of the paint. Types of paints: Interlux Micron CSC, Interlux Micron Extra with Biolux.
? SELF-POLISHING COPOLYMERS ? SPC technology antifoulings work because the film contains a patented resin called an ?SPC Copolymer?. This copolymer reacts with saltwater in a controlled way. As a result, the chemical reaction controls and sustains the release of biocides throughout the lifetime of the antifouling without decline. This chemical reaction will take place at the same rate whether you boat is underway or sitting at the dock. This type of technology has previously only been available in tin-based copolymer coatings, which are restricted in their use to boats over 82 feet in length. This new, patented Interlux® technology is available for professional application to boats of all sizes. It is not recommended for use in fresh water. Types of Paints: Interlux Micron 66.
Some Common Questions
? How do I know the product I want to apply is compatible with my old paint already on the boat? Most antifouling paints made today can be applied over top of any type of antifouling paint. As a precautionary measure you can use Interlux Primcon as a tie coat which will bond the two types together. If the paint is old and in poor condition consider removing the old paint.
? What is Biolux? Biolux is a unique additive added to some paints that has organic boosting biocides which stop slime build up on the bottom of your boat. It acts almost like a sunscreen for the bottom of your boat.
? What is Osmosis? Osmosis is a process of degeneration within a fiberglass laminate. It is caused by a chemical reaction between water and unreacted substances remaining in the manufactured hull. The water enters the hull through the gelcoat and once inside, reacts with the chemical components creating acidic substances. These substances create pressure behind the gelcoat, which causes blisters and eventually cracking. Once the gelcoat is breached in this manner, the underlying laminate is capable of absorbing water like a sponge. Osmosis is not only caused by water on the outside of the hull ? bilge water from the inside can also cause a problem. It is therefore worth making efforts to keep your bilges dry.
? What steps are taken when painting a new boat? First you must scrub the surface with soap and water while using a stiff brush. Rinse it off with fresh water and allow drying. Next apply Interlux Solvent Wash 202 with a clean cheesecloth or rag and wipe dry before the liquid evaporates. Only do small sections at a time. This gets off any oils, mold release, or dirt. Next apply one coat of Fiberglass No Sand Primer. Use a solvent resistant 1/8 foam roller to apply the primer and paint in a direction without overcoating. Let the primer sit and dry for at least 30 minutes. To check to see if the primer is ready to overcoat use the Thumb Print test. If the primer feels tacky and you can leave a thumb print in the primer without any coming off then you are ready to the bottom paint. If the primer does stick to you thumb after the 30 minutes, wait 15 minutes and test again. Continue to do this until the primer reaches the ?Ready to Overcoat? stage.
? How much paint do I need? For a rough estimate multiply the length of you hull(LOA) by the beam and then multiply by 0.85. LOA x B x 0.85 = Area. Then look on the can of paint and check the coverage. Here is a ratio for most power boats ? (LOA/Quarts) 20/3, 25/4, 30/6, 35/8, 40/10.
? How long can I leave the boat out of the water before I launch? Most antifouling paints will be fine for up to 60 days out of the water before launching. After 60 days the paints starts to rapidly lose it?s properties and may not work properly. Waterbased paints can be block for up to a year before being launched.
? Does the amount of copper in an antifouling paint effect the performance? The level of copper is not the only determining factor of how an antifouling paint will perform. The resin-binder system, the material that holds the paint together, is equally important. Not only does the resin-binder system hold the paint together, it is the mechanism that determines how fast the copper and other biocide will be released. The resin-binder system must be carefully tailored for the amount and type of copper and other biocides used to obtain maximum efficiency The amount of copper or other biocide may effect the life of an antifouling paint but the sophistication of the resin-binder system to hold and release copper or other biocide at the proper rate is far more important to the effectiveness of the anti-fouling. A copolymer or ablative anti-fouling will release biocide at nearly constant rate throughout its life. For this reason, highly efficient antifouling paints like Micron are less dependent on large amounts of copper and other Biocides and deliver the best possible performance. The use of boosting biocides in combination with Biolux Technology keeps the bottom clear of slime and makes the copper more effective.
? What is Irgarol? A product similar to Biolux that stops slime, algae, and weed build up on the bottom of your boat. A brand new product this year that is found in Interlux ACT paints.
? Can I thin antifouling paints? Antifouling paint performance in general terms is dependent upon the film thickness applied at application time. Interlux antifoulings are formulated to the optimum viscosity, or thickness, for their designed application thickness. Thinning can significantly affect the application properties of an antifouling.
? What type of antifouling paint can I use on aluminum? Trilux 33 with Biolux is specifically developed for use all surfaces including aluminum boats, outdrives, and outboards. Trilux 33 with Biolux, unlike other antifouling paints, does not use cuprous oxide. Trilux 33 uses Cuprous Thiocyanate. Cuprous Thiocyanate is safer to use then Cuprous Oxide. The biocides work together to fight shell fouling such as barnacles and zebra mussels while the Biolux blocks slime and algae. This blend of resins and biocides, when properly applied over primer, offer excellent antifouling protection. While Trilux 33 has been specifically developed for use on primed aluminum, it can also be applied to fiberglass, wood and other underwater metals on boats. You could also use Pettit Alumacoat or Aquagard antifouling sprays.
? How do I remove old bottom paint? There are a few different ways to remove bottom paint off the hull of your boat. Sand blasting, strippers, or hydro/dry ice blasting are all effective ways to remove bottom paint. Sand blasting is a fast but it is messy and can do damage to the gelcoat. Hydro/Dry Ice blasting is expensive and must be done by a professional. Stripping the boat with Interlux 299E is the easiest way for the do-it-yourselfer. First lay an old tarp down under the boat and apply the 299E with a hard stiff brush to about 5 times thicker then coats of paint. Let it sit for an hour or so and come back with a small paint scraper. If it does not go down to the gelcoat leave it and check it every 15 minutes until it does so. Do not let it the 299E sit on the paint for more then 8 hours or damage to the gelcoat may occur. Tip: Put on a pair of gloves and reuse the old stripper that fell onto the tarp. This can be done may times until the stripper has no effect anymore.
? What is Interprotect and how does it work? Interprotect is a unique two part epoxy designed to reduce the potential of water absorption by fiberglass hulls. Interprotect is
unique among epoxies because it has microplates, which are a protective barrier within its film to slow down water permeation. Technically, Interprotect microplates provide millions of overlapping microscopic plates that create a barrier similar to shingles on a roof. These overlapping microplates eliminate any direct path for water migration and also improve the sag resistance of the epoxy making application easier. Four to five coats of Interprotect are recommended to ensure complete protection. Do not exceed any of the dry times in between coats(14 days) or you must sand with 80 grit sandpaper and re-apply an extra coat. Also on a 70 degree day, you MUST apply a coat of antifouling paint within 7 hours or you will have to apply an extra coat of Interprotect. It is now available in both gray and white and it also acts as a primer. This is a great addition to any new boat or a boat with a freshly clean/stripped hull.
