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BT - Coatings and Paints
 

BT - Coatings and Paints

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    BT - Coatings and Paints BT - Coatings and Paints Presentation Transcript

    • Class Instructor :RDAFernandez, uap
    • PRINCIPAL TYPES OFCOATINGS:  Paints  Stains  Varnishes
    • PAINTS: a solution of a pigment in water, oil, or organic solvent, used to cover wood or metal articles either for protection or for appearance
    • FUNCTION/PURPOSE An economic method of surface protection and preservation to building materials and components. An economic method of surface decoration to building materials and components.
    • PAINTSCLASSIFICATION: Architectural Paints are air-drying materials applied by brush or spray to architectural and structural surfaces and forms for decorative and protective purposes Commercial Paints air-drying or baking-cured materials applied by brush, spray, or magnetic agglomeration to kitchen and laundry appliances, automobile, machinery, and furniture and used as highway marking materials
    • PAINTSCLASSIFICATION: Industrial Paints subdivided by their intended service: corrosion- resistant coatings, high temperature coatings, and coatings for immersion service
    • PAINTCOMPOSITION: Pigment gives the paint a colour, but also plays a role in its consistency, ease of application, drying ability, durability and hardness “Varnish – no pigment” Vehicle a liquid in which pigment is dispersed before being applied to a surface in order to control consistency, adhesion, gloss and durability
    • PAINTCOMPOSITION:Pigment Constituents CommentsLead white Basic lead carbonate Highly poisonousYellow ochre Hydrated ferric oxide Highly tolerant externallyCadmium yellow Cadmium sulphide Highly poisonousRed ochre Ferric oxide An earth pigmentChrome red Basic lead chromate Highly poisonousPrussian blue Ferric ferrocyanide PoisonousCobalt blue Cobalt aluminate PoisonousZinc green Zinc chromate Highly poisonousUmber Clay w/ iron & mang. From ferric oxideBurnt Sienna Hydrated ferric oxide An earth pigmentLamp Black Carbon
    • PAINTCOMPOSITION: Binder binder makes the coat of paint retain its structure, and binds it to the surface to which it is applied “Stain – no binder” Solvent solvent dissolves the paint to make it usable at normal room temperatures
    • PAINTCOMPOSITION:Type of Paint Solvent Areas of Useor Binder Inside OutsideCement Paint water x xEpoxide Paint/Varnish xylene, butanol, ethyl x x gycol, methyl isobutyl, ketone, glycolPolyurethane ethyl acetate, butyl x x acetate, ethyl glycol acetate, tolueneAlkyd Oil/Varnish xylene, toluene x xAcryl Latex Paint water x x
    • PAINT TYPES:  Primers are basecoats applied to a surface to improve the adhesion of subsequent coats of paint or varnish  Sealers are basecoats applied to a surface to reduce absorption of subsequent coats of paint or varnish, or to prevent bleeding through the finish coat
    • PAINT TYPES: Oil Paints utilize a drying oil that oxidizes and hardens to form a tough elastic film when exposed to thin layer of air. Alkyd Paints have as a binder an alkyd resin, such as chemically modified soy or linseed oil.
    • PAINT TYPES: Latex Paints have as a binder an acrylic resin that coalesces as water evaporates from the emulsion. Epoxy Paints have an epoxy resin as a binder for increased resistance to corrosion, abrasion and chemicals.
    • PAINT TYPES: Rust Inhibiting Paints & Primers are esp. formulated with anti-corrosive pigments to prevent /reduce the corrosion of metal surfaces. Fire Retardant Paints are especially formulated with silicone and polyvinyl chloride or other substance to reduce the flame spread of a combustible material.
    • PAINT TYPES: Heat Resistant Paints are specially formulated w/ silicone resins to withstand high temperatures Intumescent Coatings, when exposed to the heat of a fire, swell to form a thick insulating layer of inert foam that retards flame spread and combustion
    • STAINS: Stain is a solution of dye or suspension of pigment in a vehicle, applied to penetrate and color a wood surface without obscuring the grain Penetrating stain permeate a wood surface, leaving a very thin film on the surface
    • STAINS: Water Stain A penetrating stain made by dissolving dye in a water vehicle. Spirit Stain A penetrating stain made by dissolving dye in an alcohol or spirit vehicle.
    • STAINS: Pigmented Stain Or opaque stain is an oil stain containing pigments capable of obscuring the grain and texture of a wood surface Oil Stain Made by dissolving dye or suspending pigment in a drying oil or oil varnish vehicle.
    • VARNISHES: Varnish is a liquid preparation of a resin dissolved in an oil or in alcohol that when spread and allowed to dry forms a hard, lustrous and transparent coating. Oil based are oil varnish while alcohol based are spirit stain.
    • VARNISHES: Spar Marine varnish is a durable, weather resistant varnish made from durable resins and linseed or tung oil. Polyurethane Varnish of exceptionally hard, abrasion resistant and chemical resistant varnish made from plastic resin of the same name.
    • VARNISHES: Lacquer Refers to any of various clear or colored synthetic coatings consisting of nitrocellulose or other cellulose derivative dissolved in a solvent that dries by evaporation to form a high gloss film. Shellac Spirit varnish made by dissolving purified lac flakes in denatured alcohol.
    • PAINTS CAN BEAPPLIED BY: Brush Spray Roller
    • SURFACE PREPARATION(Exterior):Previously painted surfaces: Scrape off loose paint and sand smooth. Old, fading paint must be removed to provide good adhesion for the new coats of paint. Nail back loose boards, countersink the nail heads and fill with putty. To prevent discoloration of paint later, seal knots and resinous spots with a thin coat of shellac.
    • SURFACE PREPARATION(Exterior):New wood exteriors: The surface must be clean and dry Rough spots in siding should be sanded smooth All new wood must be primed After the prime coat has been dried, putty and fill all nail holes and cracks Caulk joint around doors and window frames If pre-primed siding is hard and slick, it should be re-primed
    • SURFACE PREPARATION(Exterior):Masonry floors: Interior and exterior concrete floors must be allowed to dry approximately 90 days for proper aging. Fresh cement contains alkali which will burn paint. Floors subjected to excessive moisture seepage, or hydrostatic pressure, cannot be successfully painted.
    • SURFACE PREPARATION(Exterior):Metal surfaces: All metal surfaces must be cleaned and dry Remove any rust, mill scale or loose paint by wire brushing, sandblasting/sandpapering. Bare spots on shop-coated steel must be wire- brushed and spot primed. Remove oil and grease with paint thinner or mineral spirits. No priming necessary when applying exterior latex to weathered galvanized metal.
    • SURFACE PREPARATION(Interior): The surface to be painted must be clean and free of wax, dirt or grease Cracks and holes must be repaired with patching plaster Patched areas must be spot primed Old glossy surfaces should be prepared by sanding
    • PROPER APPLICATION: Avoid painting in the hot sun. Try to paint those surfaces that have already been exposed to sunlight Apply a coat of paint primer Finish with two-coat of top coats
    • PAINT DEFECTS(Interior): Bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface
    • PAINT DEFECTS(Interior):Possible Causes:•Applying oil-based or alkyd paint over a damp or wet surface•Moisture seeping into the home through the exterior walls•Exposure of the latex paint film to high humidity or moisture shortly after paint has dried, especially if there was inadequate surface.Solution:•If blisters do not go all the way down to the substrate: Remove blisters by scraping & sanding, and repaint with a quality acrylic latex interior paint.•If blisters go down to the substrate: Remove the source of moisture, if possible.
    • PAINT DEFECTS(Interior): Undesirable sticking together of two painted surfaces when pressed together (e.g., a door sticking to the jamb)
    • PAINT DEFECTS(Interior):Possible Causes:•Not allowing sufficient dry time for the coating before closing doors or windows.•Use of low quality semi-gloss or gloss paints.Solution:•Use top quality semi-gloss or gloss acrylic latex paint. Acrylic latex paints generally have better early block resistance than vinyl latex paints, or alkyd or oil-based paints
    • PAINT DEFECTS(Interior): Increase in gloss or sheen of paint film when subjected to rubbing, scrubbing or having an object brush up against it.
    • PAINT DEFECTS(Interior):Possible Causes:•Use of flat paint in highly trafficked areas, where a higher sheen level would be desired.•Frequent washing and spot cleaning.•Objects (furniture, for example) rubbing against the walls.Solution:•Paint heavy wear areas that require regular cleaning (e.g., doors, window sills and trim) with a top quality latex paint•In high traffic areas, choose a semi-gloss or gloss rather than a flat sheen level
    • PAINT DEFECTS(Interior): The splitting of a dry paint film through at least one coat as a result of aging, which ultimately will lead to complete failure of the paint. In its early stages, the problem appears as hairline cracks; in its later stages, flaking occurs.
    • PAINT DEFECTS(Interior):Possible Causes:•Use of a lower quality paint that has inadequate adhesion and flexibility.•Over-thinning or overspreading the paint.•Inadequate surface preparation, or applying the paint to bare wood without first applying a primer.Solution:•Remove loose and flaking paint with a scraper or wire brush, sanding the surface and feathering the edges.•Prime bare wood areas before repainting.•Use of a top quality primer and top coat should prevent a recurrence of the problem.
    • PAINT DEFECTS(Interior): Formation of bubbles (foaming) and resulting small, round concave depressions (cratering) when bubbles break in a paint film, during paint application and drying.
    • PAINT DEFECTS(Interior):Possible Causes:•Shaking a partially filled can of paint.•Use of low quality paint or very old latex paint.•Applying (especially rolling) paint too rapidly.•Excessive rolling or brushing of the paint.•Applying a gloss or semi-gloss paint over a porous surface.Solution:•Use high quality paints which will allow good flow and appearance•Avoid excessive rolling or brushing of the paint or using paint that is more than a year old.•Apply an appropriate sealer or primer before using such paint over a porous surface.•Problem areas should be sanded before repainting.
    • PAINT DEFECTS(Interior): Lapping: Appearance of a denser color or increased gloss where wet and dry layers overlap during paint application.
    • PAINT DEFECTS(Interior):Possible Causes:•Failure to maintain a "wet edge" when painting.•Use of a low solids "economy" paint.Solution:•Maintain a wet edge when painting by applying paint towardthe unpainted area and then back into the just-paintedsurface. This technique will produce a smooth, uniformappearance. It is also wise to work in manageable-size areas;plan for interruptions at a natural break, such as a window,door or corner. Using a top quality acrylic latex paint makes iteasier to avoid lapping problems because high solids(pigments and binder) content makes lapped areas lessnoticeable. Alkyd paints generally have superior wet edgeproperties.
    • PAINT DEFECTS(Interior): Mildew: Black, grey or brown spots or areas on the surface of paint or caulk.
    • PAINT DEFECTS(Interior):Possible Causes:•Forms most often on areas that tend to be damp, or receivelittle or no direct sunlight (bathrooms, kitchens, laundry rooms)•Use of an alkyd or oil-based paint, or lower quality latex paint.•Failure to prime wood surface before applying the paint.•Painting over a substrate/coating on which mildew has notbeen removed.Solution:•Test for mildew by applying a few drops of household bleachto the area: if it is bleached away, the discolorant is probablymildew. Remove all mildew from the surface by scrubbing witha diluted household bleach solution (one part bleach, threeparts water) Rinse thoroughly. Use a top quality latex paint, andclean when necessary with bleach/detergent solution. Considerinstalling an exhaust fan in high moisture areas.
    • PAINT DEFECTS(Interior): Mud Cracking: Deep, irregular crack resembling dried mud in dry paint film.
    • PAINT DEFECTS(Interior):Possible Causes:•Paint is applied too thickly, usually over a porous surface.•Paint is allowed to build up in corners upon application.Solution:•Remove coating by scraping and sanding. Prime and repaint,using a top quality latex paint. Mud-cracked areas can also berepaired by sanding the surface smooth before repainting witha top quality latex paint. Quality paints have a higher solidscontent, which reduces the tendency to mud crack. They alsohave a very good application and hiding properties, whichminimize the tendency to apply to thick a coat of paint.
    • PAINT DEFECTS(Interior): Sagging: Downward "drooping" movement of the paint film immediately after application, resulting in a uneven coating.
    • PAINT DEFECTS(Interior):Possible Causes:•Application of a heavy coat of paint.•Application in excessively humid and/or cool conditions.•Airless spraying with the gun too close to the substrate beingpainted.Solution:•If paint is still wet, immediately brush out or re-roll to redistributethe excess evenly. If the paint has dried, sand and reapply anew coat of top quality paint. Correct any unfavorableconditions: Do not thin the paint; avoid cool or humid conditions;sand glossy surfaces. Paint should be applied at itsrecommended spread rate are better than one heavy coat,which can also lead to sagging. Consider removing doors topaint them supported horizontally.
    • PAINT DEFECTS(Interior): Surfactant Leaching: Concentration of water-soluble ingredients on the surface of a latex paint, typically on a ceiling surface in rooms that have high humidity (e.g., shower, bathroom, kitchen); may be evident as tan or brown spots or areas, and can sometimes be glossy, soapy or sticky.
    • PAINT DEFECTS(Interior):Possible Causes:•All latex paint formulas will exhibit this tendency to someextent if applied in areas that become humid (bathrooms, forexample), especially in ceiling areas.Solution:•Wash the affected area with soap and water, and rinse.Problem may occur once or twice again before leachablematerial is completely removed. When paint is applied in abathroom, it is helpful to have it dry thoroughly before using theshower. Remove all staining before repainting.
    • PAINT DEFECTS(Interior): Wrinkling: A rough, crinkled paint surface, which occurs when uncured paint forms a "skin.”
    • PAINT DEFECTS(Interior):Possible Causes:•Paint applied too thickly (more likely when using alkyd or oil-based paints).•Painting during extremely hot weather or cool damp weather,which causes the paint film to dry faster on top than on thebottom.•Exposure of uncured paint to high humidity levels.•Applying top coat of paint to insufficiently cured primer.•Painting over contaminated surface (e.g., dirt or wax)Solution:•Scrape or sand substrate to remove wrinkled coating. If usinga primer, allow it to dry completely before applying top coat.Repaint, (avoiding temperature/humidity extremes), applyingan even coat of top quality interior paint.
    • PAINT DEFECTS(Interior): Poor Print Resistance: Tendency of paint film to take on the imprint of an object that is placed on it (e.g., a shelf, table, window sill or countertop with books, dishes and other objects of them).
    • PAINT DEFECTS(Interior):Possible Causes:•Use of low quality semi-gloss or gloss paint.•Putting a painted surface back into use before paint has fullydried.Solution:•Use top quality acrylic semi-gloss or gloss latex paint. Lowquality latex semi-gloss and gloss paints can have poor printresistance, especially in warm damp conditions. Acrylic latexpaints generally have better print resistance than vinyl latexpaints. Fully cured alkyd paints also have excellent printresistance. Make sure the recommended "cure" time is allowedfor the paint before it is put into service. Cool or humidconditions require more curing time.
    • PAINT DEFECTS(Exterior): Alligatoring: Patterned cracking in the surface of the paint film resembling the regular scales of an alligator.
    • PAINT DEFECTS(Exterior):Possible Causes:•Application of an extremely hard, rigid coating, like an alkydenamel, over a more flexible coating, like a latex primer.•Application of a top coat before the undercoat is dry.•Natural aging of oil-based paints as temperaturesfluctuate. The constant expansion and contraction results in aloss of paint film elasticity.Solution:•Old paint should be completely removed by scraping andsanding the surface; a heat gun can be used to speed work onlarge surfaces, but take care to avoid igniting paint/substrate.The surface should be primed with a high quality latex or oil-based primer, then painted w/ a top quality exterior latex paint.
    • PAINT DEFECTS(Exterior): Chalking: Formation of fine powder on the surface of the paint film during weathering, which can cause color fading. Although some degree of chalking is a normal, desirable way for a paint film to wear, excessive film erosion can result in heavy chalking.
    • PAINT DEFECTS(Exterior):Possible Causes:•Use of a low-grade, highly pigmented paint.•Use of an interior paint for an outdoor application.Solution:•First remove as much of the chalk residue as possible, using astiff bristle brush (or wire brush on masonry) and then rinsethoroughly with a garden hose; or use power washingequipment. Check for any remaining chalk by running a handover the surface after it dries. If noticeable chalk is still present,apply a quality oil-based or acrylic latex primer (or comparablesealer for masonry), then repaint with a quality exterior coating;if little or no chalk remains and the old paint is sound, nopriming is necessary.
    • PAINT DEFECTS(Exterior): Dirt Pickup: Accumulation of dirt, dust particles and/or other debris on the paint film; may resemble mildew.
    • PAINT DEFECTS(Exterior):Possible Causes:•Use of low quality paint, esp. lower grades of satin/semi-gloss•Soil splashing onto siding.•Air pollution, car exhaust and flying dust collecting on housebody and horizontal trim.Solution:•Wash off all surface dirt before priming and painting. If unsurewhether the problem is dirt/mildew, conduct a simple spot test.Clean off dirt with a scrub brush and detergent solution, followedby a thorough rinsing with a garden hose. While dirt pickup cantbe eliminated entirely, top quality exterior latex paints typicallyoffer superior dirt pickup resistance & washability. Also, highergloss paints are more resistant to dirt pickup than flat paints,which are more porous and can more easily entrap dirt.
    • PAINT DEFECTS(Exterior): Efflorescence/Mottling: Crusty, white salt deposits, leached from mortar or masonry as water passes through it.
    • PAINT DEFECTS(Exterior):Possible Causes:•Failure to adequately prepare surface by removing all previousefflorescence.•Excess moisture escaping through the exterior masonry wallsfrom the inside.Solution:•Eliminate the source of excessive moisture by repairing the roof,cleaning out gutters & downspouts, & sealing any cracks in themasonry. If moist air is originating inside the building, considerinstalling vents/exhaust fans, esp in kitchen, bathroom & laundryareas. Remove the efflorescence & all loose material w/ a wirebrush; then thoroughly rinse the surface. Apply a quality water-based or solvent-based masonry sealer and allow it to drycompletely; then apply a coat of top quality exterior paint orelastomeric wall covering.
    • PAINT DEFECTS(Exterior): Frosting: A white, salt-like substance on the paint surface. Frosting can occur on any paint color, but it is less noticeable on white paint or light tints. On masonry, it can be mistakes for efflorescence
    • PAINT DEFECTS(Exterior):Possible Causes:•Forms mostly in protected areas (such as under eaves and onopen porch ceilings) that do not receive the cleansing action ofrain, dew and other moisture.•Use of dark-colored paints•Application of a dark-colored paint over a paint or primercontaining calcium carbonate extender.Solution:•Frosting can be a stubborn problem & cannot be washed offreadily. The condition can recur even as a bleed-through when anew top coat is applied. In extreme cases, it can interfere withadhesion. The best remedy is removing frosting by wirebrushingmasonry/sanding wood surfaces; rinse, then apply a alkyd-based primer before adding a coat of high quality exterior paint
    • PAINT DEFECTS(Exterior): Paint Incompatibility: Loss of adhesion where many old coats of alkyd or oil-based paint received a latex top coat.
    • PAINT DEFECTS(Exterior):Possible Causes:•Use of water-based latex paint over more than three or fourcoats of old alkyd or oil-based paint may cause the old paint to"lift off" the substrate.Solution:•Repaint using another coat of alkyd or oil-based paint. Orcompletely remove the existing paint and prepare the surface-cleaning, sanding and spot-priming where necessary- beforerepainting with a top latex exterior paint.
    • PAINT DEFECTS(Exterior): Peeling: Loss of paint due to poor adhesion. Where there is a primer and top coat, or multiple coats of paint, peeling may involve some or all coats.
    • PAINT DEFECTS(Exterior):Possible Causes:•Seepage of moisture through uncaulked joints, worn caulk orleaks in roof or walls.•Excess moisture escaping through the exterior walls (morelikely if paint is oil-based).•Inadequate surface preparation.•Use of lower quality paint.•Applying an oil-based paint over a wet surface.•Earlier blistering of paint.Solution:•Try to identify and eliminate cause of moisture. Preparesurface by removing all loose paint with scraper or wire brush,sand rough surfaces, prime bare wood. Repaint with a topquality acrylic latex exterior paint for best adhesion and waterresistance.
    • PAINT DEFECTS(Exterior): Poor Alkali Resistance: Color loss and overall determination of paint film on fresh masonry.
    • PAINT DEFECTS(Exterior):Possible Causes:•Oil-based paint or vinyl acrylic latex paint was applied to newmasonry that has not cured for a full year. Fresh masonry islikely to contain lime, which is very alkaline. Until the lime has achance to react with carbon dioxide from the air, the alkalinity ofthe masonry remains so high that it can attack the integrity ofall paint film.Solution:•Allow masonry surfaces to cure for at least 30 days, andideally for a full year, before painting. If this is not possible, thepainter should apply a quality, alkali-resistant sealer or latexprimer, followed by a top quality 100 percent acrylic latexexterior paint. The acrylic binder in these paints resists alkaliattack.
    • PAINT DEFECTS(Exterior): Poor Galvanized Metal Adhesion: Paint that has lost its adhesion to a galvanized metal substrate.
    • PAINT DEFECTS(Exterior):Possible Causes:•Improper surface preparation, such as inadequate rustremoval.•Failure to apply a primer before application of an oil-based orvinyl latex paint.•Failure to sand baked-on enamel finishes or glossy surfacesbefore painting.Solution:•Any rust on the metal should be removed with a wire brush;then an acrylic latex corrosion-resistant primer should beapplied before applying an oil-based or vinyl latex top coat.
    • PAINT DEFECTS(Exterior): Poor Gloss Retention: Deterioration of the paint film, resulting in excessive or rapid loss of luster of the top coat.
    • PAINT DEFECTS(Exterior):Possible Causes:•Use of an interior paint outdoors.•Use of a lower quality paint.•Use of a gloss alkyd/oil-based paint in areas of direct sunlight.Solution:•Direct sunshine can degrade the binder and pigment of a paint,causing it to chalk and lose its gloss. While all types of paint willlose some degree of luster over time, lower quality paints willgenerally lose gloss much earlier that better grades. The binderin top quality acrylic latex paint is especially resistant to UVradiation, while oil & alkyd binders actually absorb the radiation,causing the binders to break down. Surface preparation for acoating showing poor gloss retention should be similar to thatused in chalking surfaces.
    • PAINT DEFECTS(Exterior): Vinyl Siding Warp: Warping or buckling of vinyl siding panels that have been repainted.
    • PAINT DEFECTS(Exterior):Possible Causes:•Most likely cause is that vinyl siding was painted with a darkercolor paint than the original color. Dark paint tends to absorb theheat of the sun, transferring it to the substrateSolution:•Paint vinyl siding in a shade no darker than the original. Whites,off whites, pastels and other very light colors are good choices.Top quality acrylic latex paint is the best type of paint to use onvinyl siding, because the superior flexibility of the paint filmenables it to withstand the stress of expansion and contractioncycles caused by outdoor temperature changes.
    • PAINT DEFECTS(Exterior): Wrinkling: A rough, crinkled paint surface occurring when paint forms a "skin.”
    • PAINT DEFECTS(Exterior):Possible Causes:•Paint applied too thickly (more likely when using alkyd or oil-based paints)•Painting a hot surface or in very hot weather.•Exposure of uncured paint to rain, dew, fog/high humidity levels•Applying top coat of paint to insufficiently cured previous coat.•Painting over contaminated surface (e.g., dirt or wax)Solution:•Scrape or sand substrate to remove wrinkled coating. Repaint,applying an even coat of top quality exterior paint. Make sure thefirst coat or primer is dry before applying the top coat. Applypaints at the manufacturers recommended spread rate. Whenpainting during extremely hot, cool/damp weather, allow extratime for the paint to dry completely.