Ideal Temperature For Marine Paint Application
Paint can be described as a liquid material capable of being applied or spread over a metallic or non-metallic surfaces for decorative or protective purposes in which it subsequently dries or hardens to form a continuous adherent barrier coat.
Marine paints are a type of protective paints used mostly in the marine environment to protect ships, vessels, tankers, and other materials from salty water or fresh water. These paints provide a durable surface, but the paint takes a long time to dry. Marine paints has the ability to repel water and it is easy to clean too, as grease and dirt wipes away with little effort.
Marine Paint Application
Apply when air temperature is between 50-90°F (10-32°C) and the relative humidity is below 85%. Do not apply on extremely humid days (90% humidity or above) or when rain is threatening. Do not apply in the late afternoon when working outdoors as the wet film may be adversely affected by dew. When working in cooler temperatures, be sure the air and surface temperatures will remain at or above 50°F for at least 8 hours after application.
Methods of Application
The normal methods of application of marine paint coatings are by:
- Conventional Spray
- Airless Spray
- High-Volume, Low Pressure spray (HVLP)
Other methods may also be encountered, such as dipping and pouring, and more elegant adaptations of spraying such as electrostatic, powder coatings application, and automatic plants.
When painting it is important to dip the brush in paint frequently and not to ‘over-brush’ the surface, as this will result in large differences in film thickness, the natural problem with brush application. Choice of brush, both size, length and type of bristle, and shape, are essential, and the type of paint being applied will modify the selection. Thus, large flat brushes are normally used for the majority of purposes, but round brushes are better for painting bolt-heads and ‘difficult’ areas.
Roller application is faster than brush on large, flat surfaces, such as tank sides and tops and walkways and deck areas, but it is not so good for ‘difficult’ areas. It is hard to control film thickness, however, and care must always be taken that the coating is not ‘over-rolled’ in the same manner that it can be ‘over-brushed’. Choice of roller pile (short or long hair, sponge or lambs wool) is dependent on type of coating and roughness and irregularity of surface being coated.
This is a widely accepted, rapid method of applying paint to large surfaces. The equipment is relatively simple and is usually confined to fairly low-viscosity paints, although newer techniques using ‘pressure-pot’ or ‘hot spray’ apparatus allow application of some of the ‘higher build’ type coatings. Whatever type of equipment is used, the mechanisms is the same.
Paint and air are fed separately to the spray gun and mixed at the nozzle, where the paint is atomized and air is mixed with these droplets forming a fine mist of paint which is carried by the air pressure to the work surface. It is important to have only sufficient air to provide good atomization, as excess air gives rise to overspray and ‘rebound’ from the work surface.
The gun should be held at right angles to the work surface with the nozzle some 6-8” (15-20 cms) away. Normal air pressure is from 40-80 psi (2.8-5.6 kg/cm2). The pattern of the ‘fan’ so produced is controlled by adjusting the air and fluid pressures.
By far the most important and efficient method for the application of heavy duty marine coatings. As the name implies, it is a technique of spray application which does not rely on the mixing of the paints with air to provide atomization, which is achieved by forcing the paint through a specially designed nozzle or ‘tip’ at very high pressures, as compared with air pressure associated with conventional spray, 2500-3500 psi, (176-246 kg/cm2).
High-Volume, Low Pressure Spray
High-Volume, Low Pressure spray systems use a high volume of air delivered at 10 psi or less to atomize a coating into a soft low velocity pattern.
We also offer products for the harshest marine environments, such as coatings to protect offshore structures that are submerged in tidal areas, as well as commercial trading vessels. If you’re not sure which marine coating you may need, visit GZ Industrial Supplies online store for a rundown of our portfolio.
Paints are mixtures of many raw materials, each of which in turn has been manufactured to give certain specific properties. Basically, however, paints consist of three major components and many additives which are included in minor properties. The major components are:
- Binder (other terms used include: vehicle, medium, resin, film, polymer)
- Pigment and extender
Binders are the film forming components of paint. They are predominant in determining the principle characteristics of the coating, both physical and chemical. Paints are generally named after their binder component (e.g. epoxy paints, chlorinated rubber paints, alkyd paints, etc.). The function of the binder is to give a permanent continuous film which is responsible for adhesion to the surface and which will contribute to the overall resistance of the coating to the environment.
Pigments And Extenders
Pigments and extenders are used in paints in the form of fine powders. These are dispersed into the binder to particle sizes of about 5-10 microns for finishing paints and approximately 50 microns for primers.
Solvents are used in paints principally to facilitate application. Their function is to dissolve the binder and consequently reduce the viscosity of the paint to a level which is suitable for the various methods of application, i.e. brush, roller, conventional spray, airless spray, dipping, etc. After application, the solvent evaporates and plays no further part in the final paint film, the solvent therefore becomes a high cost waste material.
Good surface preparation is, perhaps, the most significant part of the entire coating job, given that the greatest percentage of coating failures can be traced directly to poor surface preparation. No paint system will give finest performance over a poorly prepared surface. All paint systems will fail prematurely unless the surface has been properly prepared to receive the coating material. If contaminants such as oil, grease, dirt, salts, chemicals, etc. are not removed from the surface to be coated, adhesion will be conceded, and/or osmotic blistering will occur.
The marine coatings market is projected to grow at a CAGR of more than 6.8% over the period 2014–2019, in terms of volume. One of the key factors contributing to this market growth is the expansion of the oil & gas market. Also, ships in the oceans are subject to harsh environments and the constant need for their maintenance and repair can be a significant driver to sustain market demand in the years to come. The market has also been witnessing the growing consumer preference for eco-friendly products; however, the strict environmental regulations could pose a challenge to the growth of this market.
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