Abrasimeter
Laboratory instrument for the measurement of abrasion resistance.
Abrasion
Rubbing action on a polymerized coating film which must resist to the friction of particles and abrasive bodies.
Abrasive
Material of considerable hardness, used for the preparation of raw wood and the sanding of the basecoat.
Accelerator
Substance that increases the speed of a chemical reaction or of a process in general.
Acrylic
Synthetic polymer used in high performance water-based coatings. As a coating binder, acrylic resins allow the coating to last longer and to maintain their colour.
Additive
Substances, mostly chemical, suitable to confer specific properties to a product or to improve or preserve some features.
Adhesion
Ability of the coating to stick to a surface or to the underlying coating coat.
Alteration (chromatic)
Modification of the natural color of the wood, due mostly to fungi attacks.
Antique effect
Treatment to make the wood look older or antique.
Anti-yellowing
Product avoiding yellowing effect.
Antiseptic
Substance which, if applied to wood, gives a particular resistance, or even immunity, to the attacks of fungi (and in the alternative of insects).
Applicability
Ease of application of a coating or a coating system.
Accelerated Aging Process
Processes reproducing in an artificial and accelerated way the aging process of the normal conditions of use of an object.
Anchoring
Capacity of adhesion between the support and the basecoat or between the basecoat and the subsequent coats.
Binder
Substance that added to a set of free particles of another material allows to obtain from them a single whole for constructive purposes.
Bactericidal
Substance protecting the coating, in its container, and the wood from the aggression of micro-organisms existing in the air.
Bubbles
Flaw occurring with the formation of blisters in the coating film.
Beading machine
Machines used in the field of the wood to apply a plastic or wooden edge to panels.
Bénard cells
The evaporation of the components, after the application of a covering enamel, changes the surface tension of the coating product since a variation of the concentration in the system is determined. At the same time the viscosity value of the applied coating also varies and ascensional currents of solvent are created from the inner coats towards the surface and this causes turbulence inside the product which influences the surface features. The most volatile and lighter particles are transported on the surface while the heavy ones, due to their different density and size, remain at the bottom. On the surface of the coating film the stains of different sizes are called Bénard cells. These cells have a high tension at the edges which tends to decrease towards the central areas.
Build
Capacity of the coating product to cover the original colour.
Basecoat
Product having a fundamental role for the final result of the entire coating system, increasing its resistance to the various chemical-physical stresses.
Brittleness
Tendency of the dried coating film to crack or chip when subjected to deformation stresses.
Bleaching
Anomaly of a coating caused by the incorporation of moisture and / or air during the drying phase and can be caused by heat and by chemical and / or atmospheric agents.
Brush (1)
Tool for manual application of coating products.
Brush (2) (application)
Manual application of the coating by means of the brush.
Bleeding (or “bleed through”)
Discolouration of the original coating in the repairing enamel film.
Brushing
Cleaning of the surface to be painted from dust residues using a fiber or fabric brush.
Blocking
Glueing between two coated surfaces that come into contact at high temperatures and pressures.
Coating booth
Structure in which the coating is sprayed.
Charges
Substances which can change the chemical-mechanical resistance features of the coatings.
Catalysis
Chemical reaction in which two or more components of coating products, appropriately mixed, begin to harden to create the film of coating.
Catalyst
Chemical substance capable of causing catalysis, acting during a chemical reaction.
Coating system
(1) Application procedures of coating products on objects, consisting in application of dyes, basecoat, sanding and topcoat.
(2) Coating systems (types of)
- Flow coating (see "Flow Coating")
- Immersion (see "Diving")
- By Brush (see "Brush")
- By Roller (see "Roller")
- Spray (see "Spray gun")
- Spray (see "Spray")
- A rag (see "Rag (2) (application)")
- Electrostatics (see "Spray gun")
- Curtain coating: application by a curtain of coating that falls perpendicular to the object to be painted on a conveyor belt.
Coalescent
Solvent which is introduced into water-based coatings in order to facilitate the formation of the film at ambient temperature.
Cold-check
Capacity of the coating film to withstand certain cycles of low and high temperatures without cracking.
Colour
It is made of organic and inorganic pigments. The variations that can be obtained are almost endless. The colour shades can be customized or made according to recognized references: British Standard - Munsell - NCS - RAL- Pantone. The degree of tonality of a colour can be pastel (very light) - medium (medium intensity) - strong (concentrated). Depending on the used pigments, it is possible to obtain light resistances of different types: low - medium - high.
Compatibility
Union of different liquid products that create a stable transparent solution without increasing the viscosity of the system.
Conductivity
Property of a body to transmit electrical charges, used in the electrostatic application of coating products.
Cratering
Anomaly of the coating film consisting in cavities of different diameters over it.
Chromatography
Separation process of the components of a homogeneous mixture, based on the distribution of its components between two phases, one stationary and one moving along a defined direction.
Chemical formula
Representation indicating which and how many atoms compose the molecule of a substance, also showing their arrangement in space.
Can
Container made of a sheet of soft iron coated on the two surfaces by a protective layer of tin, sealed, mostly parallelepiped, assigned to contain flammable liquids.
Colour chart
Group of colour samples joined together on one side.
Closed pore
When the wood grain is not visible.
Cissing (fishing eye)
Defect of a coating that shrinks from more or less extended areas, leaving uncovered the underlying substrate or coat.
Coating
Material made of a mixture of substances (drying oils, natural or synthetic resins, cellulose derivatives) suspended in a liquid or dissolved in a solvent. It is able to dry, creating a very adherent and resistant film.
They are divided into:
- WATER-BASED PRODUCTS
- NITRO coating products
- POLYURETHANE coating products
- POLYESTER coating products
- SYNTHETIC coating products
- ACID CATALYSIS coating products
- ACRYLIC coating products
- UV coating products.
Coating systems (2) (types of)
- Flow coating (see "Flow Coating")
- Immersion (see "Diving")
- By Brush (see "Brush")
- By Roller (see "Roller")
- Spray (see "Spray gun")
- Spray (see "Spray")
- A rag (see "Rag (2) (application)")
- Electrostatics (see "Spray gun")
- Curtain coating: application by a curtain of coating that falls perpendicular to the object to be painted on a conveyor belt.
Cracking
Anomaly of the coating film which shows cracks on the surface and / or in depth.
Chalking
Degradation of the coating film due to the decomposition of the pigments on the painted surface.
Coating system (1)
Application procedures of coating products on objects, consisting in application of dyes, basecoat, sanding and topcoat.
Curtain coater
Machine creating a continuous drop veil of coating product, under which the products to be painted run on a flat surface.
Cloth (1)
Soaked fabric suitable for applying paint.
Cloth (2) (application)
Manual application with a cloth soaked of product.
Covering
Property of the coating products to cover the colour of the support.
Density
Mass of the unit volume of a material, usually defined in gr / cm³ or kg / dm³.
Dispersion
System consisting in several phases in which one of the phases is continuous and disperses the other(s).
Drying
Evaporation phase of the volatile components: diluents, solvents etc. with subsequent polymerization of the resins, which can take place with or without the association of a specific hardener.
Dipping (application)
Application by immersion of the object in a tank with controlled speed extraction, to obtain a uniform coating.
Drying time
Time necessary to the coating film to harden.
Dilution
Quantity of diluent expressed in parts: weight or volume, added to 100 parts of a coating product, to change its application viscosity.
Dust-free time
Time process, after the application of the coating on the substrate, after which dust does not stick on the coating film.
Elasticity
Characteristic of a dried coating not showing cracks in the film, when mechanically stressed.
Emulsion
Dispersion of a fluid in the form of drops in another non-miscible fluid.
Enamel
Denomination of the coating, containing colouring pigments which make it matt.
Flash-off
Drying phase carried out between two consecutive coating applications.
Flow-coating (Application)
Application system through controlled gravity flow of a coating over the substrate.
Formaldehyde
Molecule, the simplest of aldehydes. Formaldehyde is a molecule that also has two insidious characteristics: high diffusion in the air and high toxicity. In certain concentrations, it may cause irritation to the respiratory tract and to the eyesight, especially to those suffering from allergies and asthma. If ingested or inhaled in large quantities, formaldehyde is lethal. Formaldehyde is used in the composition of resins widely used in the production of manufactured articles, coatings, glues, insulating foams. In coatings, formaldehyde is appreciated for its triple function:
- antibacterial
- antifermentative
- anti-mould.
Fungicide
Substance that defends the wood from the degrading action of moulds and fungi.
Fungus
Organism without chlorophyll, which feeds at the expense of elaborated organic materials. These materials may be residues of organisms that were living once, or an integral part of active organisms. The importance of the fungus in the field of wood is particularly notable for the phenomenon of destruction and disorganization of the wooden body that the fungus itself causes.
Fire prevention
Operation to make an object less easily combustible.
Flame maple
Aspect of the wood having stripes, lines and veins of a different colour from the background, with a sinuous pattern like the one of the waves of the sea.
Film
Thin coat applied over a surface.
Flaking
Phenomenon for which small flakes of coating lose adhesion from the substrate.
Fire-retardant coating
Coating making a material resistant to fire or limiting the development of a combustion.
Filler
Substance with high filling power and good sanding features used to smooth the support and fill the cracks.
Fibres raising
Phenomenon consisting in a rise in the wood fibres due to the contact between the water or the solvent contained in the coating.
Gloss
Reflection of the coating film hit by the incident light.
Gas chromatography
Analytical chemistry method that separates the substances composing a gaseous mixture.
Gas chromatograph
Tool used to determine the composition of a mixture of chemicals.
Glossmeter
Instrument used to measure specular reflection gloss of a surface.
Grammage
Gr/sq. mt of a coating product to apply.
Heads
Flaw creating during the drying phase, when the solvent and the air cannot evaporate, due to the formation of a film on the surface.
Hardness
Characteristic of a coating film to resist mechanical stresses: scratches, shocks, rubs, pressures, etc.
Hygrometer
Tool measuring humidity in the air.
Hardener
Substance used in formulation of a glue mixture, added with the aim of promoting or controlling the polymerization reaction of the glue.
Hardwoods
Botanical term that designates wood with a narrow cellular structure.
Handling
Partial drying time after the application of a coating film on the substrate, where it is possible to handle the painted article without leaving the fingerprint.
Impregnating stain
Liquid coating product that penetrates into the wood, modifying the characteristics of the surface without forming a film. It protects the wood from the attack of moulds and fungi and reduces the demolition action of solar radiations.
Isocyanate
Generic name of the isocyanic acid salts.
Infrared Lamps
Lamps that make the solvents evaporate and therefore facilitate the drying of the coatings.
Lacquered wood
Object coated with lacquer.
Medium Density Fibreboard
Panel made of a very fine wood fibre bound by a very strong adhesive. It is the easiest type to paint.
Melamine
In chemistry, crystalline colorless substance used for the preparation of a range of resins.
Metamerism
Effect for which a colour, which has the same shade with the same light, changes colour with different light sources.
Mixer
Tool having the purpose of mixing two or more substances, allowing a variation in the proportion of the components required.
Mixing
Process for which two or more substances, even of different viscosities, are mixed.
Moisture
Humidity rate of the wood substrate to be painted, ideal between 8% and 14%.
Neutral color
Color neither transparent nor pigmented.
Nitrocellulose
Product obtained from the nitration of cellulose. Its most important use is the manufacture of coatings and enamels.
Non-yellowing
Substance or product which avoids yellowing.
Orange peel
Flaw of the surface of the dried film.
Oil
Products having protective or decorative functions.
Opacity
Condition of non-reflection of the light.
Overspray condition
Amount of coating that disperses in the air during spray applications.
Open pore
When the wood grain is clearly visible.
Over-coating capability
Capabillity of being painted several times.
Pinholes
Flaw caused by microscopic holes in the film of a coated product.
Photoinitiator
Substance releasing, under exposure to UV lights, substances that activate the polymerization reactions of UV polyester and acrylic coatings.
Photostability
Characteristic of a coating which does not alter its color when exposed to light.
Paint sheen
Specific unit of measurement used to determine the gloss level of a coating product. The values are expressed as a percentage and define the appearance of the surface of a coating film, after drying, as a function of the incident light specularly reflected from the surface of the coating. The evaluation scale varies from a minimum value of 0 - non-reflecting surface, to the maximum value of 100, total reflection of incident light. In general, the brightness or opacity value of a product is indicated by the following terms:
- Intense matt = gloss degrees from 1 to 10
- Matt = gloss degrees from 11 to 30
- Middle average = gloss degrees from 31 to 40
- Semi matt = gloss degrees from 41 to 50
- Semi shiny = gloss of brightness from 51 to 80
- Shiny = gloss degrees from 80 to 100.
Pantone
International colour identification system. The name comes from the US company specialized in technologies for graphics, colour nomenclature and production of the identification system of the latter.
Plane (n.)
Tool for smoothing wood.
Plane (v.)
Smooth and polish the wood with the plane.
Pigments
Coloured substances giving to a coating the desired color tone.
Painting
Pigmented coating forming a covering film, when applied on a support
Polymer
Macromolecule consisting of a large number of molecular groups, joined as a chain by the same type of bond.
Polyurethane
Synthetic fibres with excellent elastic characteristics, good dyeing properties, high resistance to solvents and light.
Porosity
Anomaly of the coating film that has microscopic holes reaching the support.
Pot-life
Time within which it is possible to apply the catalyzed coating before its solidification.
Pressurisation
Process for purifying the air from dust particles and impurities in a painting room.
Primer
Pigmented product used as first coat and characterized by a great adherence to the support.
Profile
Product with linear or variously shaped dimensions.
Pitting
Anomaly due to the presence of bubbles, granules or micro holes on the film surface.
Peeling off
Detachment of the coating film from the substrate or from an underlying coat in the form of leaves or scales.
Queue de vache
Abnormal colouring of the wood, which spreads from the sides to the heart with the shape of longitudinal flames.
Runs
Accumulation during vertical application of the coating with effects of drops. This flaw is due to the excess of applied paint.
Radiometer
Instrument used in radiometry to measure the flow of electromagnetic radiation.
Ral
Standardised colour scale used mainly in the field of coverings and coatings.
Rheology
Science that studies the characteristics of deformation and sliding of materials under the action of external forces.
Rheometer
Tool used to calculate the rheology of products.
Resin
Generic name of natural or synthetic products characterized by having more or less marked plastic properties.
Retarder
Additive product which facilitates spreading the coating.
Roller (1)
Rotary brush suitable for manual application of coatings.
Roller (2) (application)
Application of coating substances with a roller.
Stackability
Drying time necessary to stack painted objects, without the risk of damaging each other.
Spontaneous combustion
Ability of a substance which can ignite spontaneously.
Sandpaper
Usually made of paper or cloth, it is used for sanding the substrate to be coated or to sand the previously applied coats. This type of paper has a part uniformly sprinkled with grains of different sizes whose units of measure are the meshes contained in a square inch (6.45 sq/cm) of the sieve, through which the abrasive grains of the paper have passed. The following table shows the most common grain sizes used:
- 40 - 60 - 80 extra coarse
- 100 - 120 - 150 coarse
- 180 - 200 - 240 medium
- 280 - 320 - 360 fine
- 400 - 500 - 600 very fine
- 700 - 800 - 900 ultrafine
Sanding
Operation preparing the support to receive the first coat of coating through the use of papers, or other abrasive means.
Scratch
Mark of abrasion on a surface.
Sealer
Product applied to prevent contact with the surface of the substrate and the subsequent coats of coating.
Softwoods
Botanical term designating wood with a wide cell structure, typical of conifers.
Solid wood
Portion of wood obtained from inner part of the of the tree (trunk), in particular from the heartwood (the oldest part).
Scraper
Abrasive tool used for sanding operations.
Scraping
Process assigned to eliminate irregularities on a surface using abrasive materials.
Spray gun
Tool for painting.
Types of equipment:
Spray gun with cup
Spray gun with tank under pressure
Airless spray gun
Air-Mix spray gun (mixed air)
Electrostatic, air or mixed air spray gun that exploits the attraction of the support towards the coating, to which is given an electric charge opposite to the one of the support itself.
Spray (application)
Spray - application of spray coating with spray gun or similar tool;
Airless - to spray the nebulized mixture without air, at medium-high and high variable pressures (from about 120 to 250 atm);
Air-mix - for spraying in intermediate conditions of nebulization, between air and airless.
Electrostatics: application carried out by means of an electric field created between the nebulizing system and the substrate to be coated.
Solid content
Part of the coating product remaining in the film after drying. With over 40% of solid content there is high coverage with 35% -40% medium-high coverage; with less than 35% medium-low coverage.
Swelling
Modification of a coating film after the absorption of liquids and vapours.
Shrinkage
Anomaly of a coating pulling back from the edges of the support during the formation of the film.
Sclerometer
Tool used to measure the hardness of minerals.
Support
Any solid surface suitable for receiving a coating system.
Substrate
Synonym of “support”.
Stain
Synonym of “tone” or “coloring matter”, that constitutes the tone itself.
Stratification
Anomaly due to the non-perfect adhesion between the different coats due to the too long interval of time between them.
Spectrophotometry
Study of electromagnetic spectrum.
Spectrophotometer
Tool allowing to study an applied product or a support through inspection and characterization, using both visual and chemical contrasts.
Spectrometer
Any tool allowing to measure the spectrum of electromagnetic radiation, or the properties of light according to its wavelength.
Solvent
Product that lowers viscosity, facilitating the application and the spreading of the coating.
Silver Stains
White-silver stains formed between the coating and the support due to the non-perfect adhesion of the coating.
Thinner
Liquid that modifies the viscosity, the drying time of the coatings, the wetting of the substrate, the application and the film-forming distension.
Topcoat
The last coat of the coating system. It can be transparent or pigmented, with different types of appearance.
Tongue and groove board
Wooden boards with grooves on the sides called male and female, which can be used for various purposes, especially in building field in the covering of walls and ceilings.
Tintometric System
System allowing to obtain dyes, using volumetric or gravimetric formulas, with electronic or manual tintometers.
Transparency
Feature of a coating that does not mask the appearance of the support.
Tintometer
Equipment dosing base colours and obtaining a pre-established colour, based on a sample case that can reach thousand colours.
Thyxotropy
Property of a coating product to remain adherent to the vertical support and allows the application without sagging.
Thickness gauge
Tool used for measuring the wet thickness of the applied coating.
Thermo-hygrometer
Tool combining a thermometer and a hygrometer, to measure the temperature and humidity of the painting environment, respectively.
Teak
Family of tropical hardwood trees. Their wood is used for the construction of objects for exterior, ship decks, musical instruments etc. This type of timber is easily workable despite its hardness.
Tannin
Chemical substance existing in plant extracts able to combine with proteins of leather in insoluble complexes, to prevent the putrefaction of proteolytic enzymes and to transform it into leather.
UV absorbers
Chemicals that stop ultraviolet radiation of the solar spectrum before it reaches the wood.
UNI standards
Rules relating to the tests to determine the quality of the finished surface of the coated articles. The UNI EN standards are those recognized in Europe.
Ultraviolet radiation
Electromagnetic radiation, belonging to the electromagnetic spectrum, with a wavelength between visible light (to the human eye) and the one of X-rays.
UV Lamps
Lamps whose ultraviolet rays harden some types of resin-based coatings.
Viscosity
Fluidity degree of a coating: it must be generally high for spray application, medium for application with curtain coater, low for roller or reverse applications.
Vehicle
Resin soluted in solvent or water improving the application of dyes.
Wetting
Process through which a liquid and a solid surface come into contact.
Wood veneer
Carpentry operation to cover a non-fine wood (or a panel) with a very thin veneer of wood.
Wrinkling
Wrinkle-shaped anomaly occurring when a film dries on the surface much more quickly than in depth.
Xylophagus
Animal that feeds on wood.
Yellowing
Procedure because of which the coating tends to become yellow or yellowish.
Yield
Paintable square meters with 1 Kg of coating ready to use.