Sale of Underwater Primer
Are you in search of underwater primer to use under antifouling coating or for another way of painting bottom parts of your yacht? Choose and buy specialized primers for yachts in this section of the topRik marketplace, which are supplied to us only by world-famous manufacturers of marine chemicals (Boero Yacht Coatings, Veneziani Yachting, Silpar TK, etc.), as well as well-established distributors (FNI, etc.)
If you find it difficult to choose a protective primer for boats, get a free professional consultation right now. topRik experts, experienced sailors, will give it to you through the website’s feedback form or by phone, the number of which is listed on this page. You can also send your questions or application to the email address [email protected].
Modern paints and varnishes are a system of heterogeneous products that are applied to the surface to be protected in a certain sequence. The material used for the first layer of a coating system is called a primer. The term “primer” often means not only the actual paint and varnish material applied to the surface, but also the coating formed from this material.
The main purpose of the primer is to ensure good adhesion between the coating layers. On metal surfaces, the primer also performs protective functions, having a significant impact on the electrochemical and diffusion processes occurring at the metal-coating interface. And on fiberglass or wood surfaces, marine primers provide waterproofing.
The properties of the primer coating, on the one hand, are determined by the chemical composition of the primer:
- the nature of the film former;
- type of pigments and fillers;
- the nature of the special additives used.
On the other hand, they largely depend on the nature of the surface to be painted and the quality of their preparation before applying coatings.
In the practice of shipbuilding and especially ship repair, primers can be applied either to bare metal, fiberglass or wood, or to a surface with remnants of an old, firmly adhering coating. In the latter case, serious complications arise, since the adhesion of paint and varnish material to “aged” coatings is usually much lower than to a clean surface.
The level of adhesion is affected by the contact area between the protected surface (substrate) and the primer. Maximum adhesive contact is achieved by applying a thin layer of primer (no more than 20 microns) and provided that the surface to be painted is well wetted with the primer. It follows that it is necessary to place special requirements on the rheological properties of primers and the content of hydrophilic, hydrophobic and other types of components in them.
Note that currently, as a rule, thixotropic epoxy primers are applied using airless sprayers. Such materials, when applied in a single layer, make it possible to obtain paint coatings with a thickness of 120-200 microns. Coatings based on such primers can simultaneously serve as an anti-corrosion coating.
How to Choose Underwater Primer for Yachts
Due to the variety of properties of surfaces to be protected with paint and varnish coatings, it is almost impossible to create a universal primer for different materials. There is currently no unified classification of primers. But historically, primers for metals are usually divided into five groups:
- insulating;
- with pigments;
- passivating;
- protective;
- phosphating.
Practice shows that underwater primer s intended for metal can, in some cases, be successfully used on non-metallic surfaces. But primers recommended for use on certain metals are sometimes completely unsuitable for other metals. Therefore, in different industries, primers are classified according to their areas of application.
In shipbuilding, primers are usually classified according to the type of surface being painted. A distinction is made between primers for steel, light and non-ferrous metals and alloys, wood, plastics, etc.
In the topRik marketplace you can buy underwater primers with universal properties. For example, one-component MISTRAL Primer is the ideal sealing layer over an existing anti-fouling coating before applying a new coating to steel or wood surfaces.
Isolating primers, regardless of their purpose, are based on inert pigments, so they can be called chemically inactive primers. The film formers used in this case can have different structures, and their choice depends mainly on the nature of the environment in which the coating is used.
The action of all other primers is based on chemical processes occurring at the interface between the bottom material and the coating and determined by the type of pigments, film formers and special additives used. Therefore, primers that are not insulating can be called chemically active primers, which include, in particular, antifouling primer.
Paints with high anti-corrosion properties are used as primers. The film of such paints must be absolutely waterproof and have good adhesion both to the clean surface being painted and to subsequent layers of other paints, which is the first condition for the strength of the entire coating.
Since the surface to which underwater primer is applied, usually after cleaning it is rough and has individual irregularities, it is necessary that the paints used for this purpose have low viscosity, that is, they are able to penetrate into all the pores of the primed surface.
Depending on the film-forming base, primers are divided into oil, varnish, artificial resin and special. The choice of primer depends on the material of the surface being primed, the conditions in which it is located, and also on the composition of the paint that is supposed to be applied over the primer.
Oil primers should be prepared using the highest quality natural (linseed and hemp) drying oils. Most often, paints containing lead or iron lead, zinc white, and zinc chromate are used as oil primers. Out of these, red lead has the highest anti-corrosion properties. However, it is also the most expensive, and therefore is used to cover steel and wooden surfaces located in the most unfavorable underwater conditions. For priming steel and wooden external surfaces that are in favorable conditions, use a cheaper iron lead primer or a mixture of lead and iron lead.
Zinc white is used as a primer mainly for coating internal wooden surfaces, which are then painted in light colors, as well as for priming galvanized and duralumin surfaces. Zinc crowns are also used for the same purposes.
Varnish primers are used to coat surfaces whose paint film must have increased strength. In addition, varnish primers with pigment in the form of aluminum powder are used to coat galvanized and duralumin surfaces, for which the use of lead or iron oxide paints is unacceptable. Varnish primers are used for priming surfaces that are then painted with oil paints or oil-varnish enamels.
Varnish primers include primers made on a polyester basis. They are supplied ready-made. The first coat of primer is applied by brush or airless spray; subsequent coats can be applied in any manner. These primers are applied on a metal surface, as well as on the remnants of an old, firmly adhering oil coating at an outside temperature of at least +15°C.
Artificial resin primers are supplied ready-made. They have different components, which is determined by their purpose, as well as the type of paint and varnish materials that will be applied to the primer.
Protective primers are classified as coatings that create anodic protection; the metal being painted becomes a cathode and does not corrode, while the metal pigment (for example, zinc dust), which acts as an anode, undergoes corrosion. As a result, the painted metal does not deteriorate as long as there is a primer on it. Such primers adhere well only to thoroughly cleaned steel. They are applied with a brush or spray gun. Protective primers are prepared from ethinol varnishes.
FAQ
What is underwater primer and why is it needed?
Underwater primer increases adhesion at the interface of the bottom material (metal, fiberglass, wood) and the covering layer, for example, of antifouling paint. At the same time, some types of underwater primer can exhibit hydrophobic, anti-corrosion and other protective properties, thereby enhancing the effect of the paint or antifouling coating.
What types of materials can underwater primer be applied to?
Manufacturers of modern marine compounds for the construction and repair of boats produce underwater primers for all types of materials from which the part of the boat below the waterline is made - metal (steel, aluminum and alloys), fiberglass, wood, etc.
How to properly prepare the surface before applying underwater primer?
Surface preparation before application underwater primer depends on its condition: how well the previous layer, for example, an antifouling coating, holds up. In any case, cleaning the surface from dirt and degreasing it is mandatory. Depending on the material and condition of the surface, putty may be necessary to repair damage or sanding to improve adhesion.
What types of underwater primers are there and what are their differences?
Existing types of underwater primers are classified both by their intended purpose and the basis of preparation. This is described in detail in the previous section.
Should I apply antifouling paint over underwater primer?
It is very advisable to apply antifouling agent on top of special antifouling primer, if the bottom and part of the hull have not previously been subjected to antifouling. Unpainted housings made of steel, aluminum, wood before applying antifouling agent must be properly primed with appropriate types of primers.
If the yacht is already painted with a suitable primer, it is enough to sand it before applying a new coat of antifouling paint.
How many layers of underwater primer you need to apply for optimal protection?
To ensure optimal protection and level of adhesion, it is better to paint the bottom in 2 layers (necessarily with interlayer drying). If enamel is applied over primer and paint, then one primer coat is sufficient.
How long should you wait between applying underwater primer layers?
There can be no general recommendations here, it all depends on the type of underwater primer. All features of the process must be indicated in the instructions for use - strictly follow the manufacturer’s recommendations.
Can I use underwater primer in cold or very wet conditions?
Here a lot depends on the material of the vessel and the manufacturer’s recommendations for the primer. For example, when painting the bottom of a fiberglass boat, the primer must completely harden at a temperature of 20°C for 7 days, and at a lower temperature - for 14 days. That is, low temperature and high humidity do not contribute to high-quality curing of underwater primer.