Surface Preparation Guide

Water Rinsing

Procedure

Wash thoroughly with fresh water all surfaces requiring the removal of slats and acids. Surfaces should be washed by either swabbing with clean brushes, rags, etc. wetted frequently with clean water or by hosting down from fresh water supply line.

All water vessels used for swabbing down the surfaces should be frequently replenished with clean water. Surfaces should be dried as quickly as possible by wiping with clean rags and / or blowing with dry, clean compressed air before proceeding with the next operations.

It is recommended that the rinsing operation be carried out preferably under dry atmospheric conditions, if possible, to assist the rate of drying. Water rinsed surfaces should be coated as soon as possible, after drying thoroughly, to prevent surface deterioration occurring.

Solvent Cleaning

Procedure

All deposits of oil, grease, or other solvent soluble contaminants should be removed from the surface by wiping or scrubbing the surface with rags or brushes wetted with solvent such as mineral turpentine or white spirit.

Final cleaning should be done by wiping down with clean solvent, using clean rags or brushes. The surface should be allowed to dry satisfactorily before proceeding with the next operation.

The solvent cleaned surfaces should be treated or primed immediately or as soon as possible where chemical contamination of the surface may occur after cleaning and before deterioration of the surface occurs.

Precautions

Do NOT use benzene (benzol).
Do NOT use petorl.
Do NOT smoke. Keep away from all sources of ignition. Avoid skin and eye contact and avoid breathing its vapour. Provide adequate ventilation during use. Wear PVC gloves and chemical goggles. If swallowed do NOT induce vomitting. Give plenty of water or milk. Obtain medical attention.

Reference:

Australian Standard 1627, Part – 1.

Hand Tool Cleaning

Preliminary Cleaning
Oil, grease etc. should be removed by solvent cleaning.
(Refer PS-601)

Removal Procedure
Remove all loose rust, loose millscale, loose paint and blistered paint by scraper. All loose millscale not readily removed by scraper should be removed by a chipping hammer.

Heavy nodules and heavy scale should be removed by a heavy impact tool. Chipping hammers should be used for removal of heavy rust, hard rust, rust scale and rust. Clean pits with hand wire brushing.

All burr marks, sharp edges, cuts, etc., made by the various cleaning tools should be ground to a smooth finish. Wire brush the entire area using hand wire brushes to clean the surface free of all loose residues left after the scraping, chipping, etc. Sufficient pressure should be applied to clean the surface without any detrimental degree of burnishing on the steel.

Equipment requirement

All hand cleaning equipment should be in good condition and give satisfactory cleaning of the surface.

Steel wire brushes should be sufficiently rigid to clean the surface and should be kept free of all foreign matter. These brushes should be discarded when they are no longer effective. Emery paper should be clean and have a good cutting surface.

Further cleaning and pre-treatment

After hand tool cleaning all deposits of oil or grease left on the surface should be removed from the surface by wiping or scrubbing with brushes or rags wetted with a suitable solvent such as mineral turpentine or white spirit. Any residues such as salts or acids left on the surface must be thoroughly washed off with clean fresh water.

The surface prior to being treated or primed should be thoroughly dry before proceeding and cleaned down with brushes, clean, dry compressed air or vacuum to remove all loose and extraneous deposits.

The cleaned surface should be treated or primed as soon as possible and before further deterioration of the surface occurs, particularly where chemical contamination is possible.

Degree of surface preparation required

In all cases the surface should be cleaned to a satisfactory standard as required by this specification.

Special attention should be given to all areas such as rivet heads, cracks, crevices, lap joints, weld areas and angles to ensure that these sections are cleaned thoroughly by using a combination of tools best suited for the operation.

Areas of tightly adhered paint not removable by the hand tool cleaning should have all edges feathered by sanders to a smooth surface. All remaining paint not removed should have sufficient adhesion so that it cannot be lifted as a layer by inserting a dull putty knife under it, and will not 'fry' or lift due to any sol­vent action by the primer.

All areas which will be inaccessible after assembly should be cleaned by hand tool cleaning assembly.

All weld flux and spatter should be removed by hand tools.

Precautions

Wear safety glasses. Observe local statutes in use of equipment.

If the surface being cleaned was previously coated with a lead based paint, an appropriate dust mask should be worn — particularly where sanding is recommended.

Power Tool Cleaning

Preliminary Cleaning
Oil, grease etc. should be removed by solvent cleaning.
(Refer PS-601)

Removal Procedure
Remove all loose rust, loose millscale, loose paint and blistered paint by scraper. All loose millscale not readily removed by scraper should be removed by a needle gun for irregular surfaces, and a descaler, for flat open surfaces.

Heavy nodules and heavy scale should be removed by descaler or heavy impact tool. Chipping hammers should be used for removal of heavy rust, hard rust, rust scale and rust. Clean pits with needle guns.

All burr marks, sharp edges, cuts, etc., made by the various cleaning tools should be ground to a smooth finish with sanders or grinders. Wire brush the entire area using rotary power wire brushes (cup or radial type) to clean the surface free of all loose residues left after the scraping, chipping, etc. Sufficient pressure should be applied to clean the surface without any detrimental degree of burnishing on the steel.

Equipment requirement

All power cleaning equipment should be in good condition and give satisfactory cleaning of the surface.

Steel wire brushes should be sufficiently rigid to clean the surface and should be kept free of all foreign matter. These brushes should be discarded when they are no longer effective.

Power grinding wheels or sanding abrasive discs should be discarded when they become ineffective.

Further cleaning and pre-treatment

After power tool cleaning: All deposits of oil or grease let on the surface should be removed by wiping or scrubbing with brushes or rags wetted with a suitable solvent such as mineral turpentine or white spirit.

Any residues such as salts or acids left on the surface must be thoroughly washed off with clean fresh water.

The surface prior to being treated or primed should be thoroughly dry before proceeding and cleaned down with brushes, clean, dry compressed air or vacuum to remove all loose and extraneous deposits.

The cleaned surface should be treated or primed as soon as possible and before further deterioration of the surface occurs, particularly where chemical contamination is possible.

Degree of surface preparation required

In all cases the surface should be cleaned to a satisfactory standard as required by this specification.

Special attention should be given to all areas such as rivet heads, crevices, lap joints, weld areas and angles to ensure that these sections are cleaned thoroughly by using the power – driven cleaning tools, or combination of such tools, best suited for the operation. Areas of tightly adhered paint not removable by the power tool cleaning should have all edges feathered by sanders to a smooth surface. All remaining paint not removed should have sufficient adhesion so that it cannot be lifted as a layer by inserting a dull putty knife under it, and will not ‘fry’ or lift due to any solvent action by the primer. All areas which will be inaccessible after assembly should be cleaned by power tool cleaning before assembly. All accessible weld flux and spatter should be removed by power tools.

Precautions

All power tool cleaning equipment should be used in accordance with the manufacturer’s specifications. Wear safety glasses.

If the surface being cleaned was previously coated with a lead based paint, an appropriate dust mask should be worn – particularly where sanding is recommended.

Blast Cleaning

This specification covers the procedures required for the preparation of steel surfaces prior to painting by removing millscale, rust, rust scale and other foreign matter by the use of abrasives propelled nozzles or by centrifugal wheels.

Preliminary cleaning

All steel surfaces which have been exposed to chemical attack or contamination should be thoroughly rinsed with clean water for the purpose of removing any salts and acid residues prior to blast cleaning.

Heavy deposits of oil or grease should be removed from the surface by wiping or scrubbing with brushes or rags wetted with a suitable solvent prior to the blasting operation. Light deposits of oil or grease may be removed by blast cleaning, but the abrasive should not be re-used as such re-use is detrimental to the surface.

Methods of blasting

The surface should be blast cleaned by any of the methods stated below to produce a minimum surface profile.

Method 1 : Open dry blasting, using compressed air blast nozzles and a suitable abrasive.
Method 2 : Closed re-circulating blasting, using compressed air blast nozzles and a suitable abrasive, e.g., vacublast.
Method 3 : Wet blasting, using compressed air blast nozzles, water and non-metallic abrasive. The abrasive water slurry should contain a temporary corrosion inhibitor such as a meta phosphate.

Standard of blasting

The standards of surface preparation have been defined by the Australian Standards Association in Australian Standard 1627:4. Four standards of surface preparation are defined:

Class 1: Light blast cleaning. The blast intensity and distribution are such that loose millscale, loose rust and loose foreign particles are removed.

This degree of preparation approximates standard Sa1, of Swedish Standard SIS 0559 00.

Class 2: Medium blast cleaning. The blast intensity and distribution are such that millscale, rust and foreign particles are substantially removed and grey metal is visible. This degree of preparation approximates Standards Sa 2 of Swedish Standard SIS 05 59 00.

Class 2½: “Near White” blast cleaning. The blast intensity and distribution are such that millscale, rust and foreign particles are removed to the extent that only traces remaining are slight stains in the form of spots and stripes.

This degree of preparation approximates Standards ‘Sa 2½ of Swedish Standard SIS 05 59 00.

Class 3: “White Metal” blast cleaning. The blast intensity and distribution are such that all millscale, all rust and all foreign particles are entirely removed. The cleaned surface should have a uniform metallic colour. This degree of preparation approximates Standard SIS 05 59 00.

Precautions

The blast cleaned prepared surface should be treated or primed with 4 hours after preparation or before the surface becomes contaminated. In the event of the surface becoming contaminated between the blast cleaning and applying the protective coating, e.g., with rust, oil, dirt or moisture, the blast cleaning procedure should be repeated.

Cleaning before coating

The surface prior to being treated or primed, irrespective of whether it has received dry blasting or wet blasting, should be thoroughly dry before proceeding and cleaned down to remove all traces of blast products.

Methods 1 and 2: Dry blasting. The surface should be brushed with clean brushes, blown off with clean, dry compressed air, or cleaned by vacuum.

Method 3: Wet blasting. The blasted surface should be cleaned by rinsing with fresh water to which sufficient corrosion inhibitor has been added to prevent rusting, or with fresh water followed by an inhibitor treatment (a suitable corrosion inhibitor is 0.05% by weight Alfloc 918 in water). This cleaning should be supplemented by brushing, if necessary, to remove any residue.

Wherever a corrosion inhibitor is used skin and eye contact should be avoided.

Refer to the Health and Safety Aspects page included in the front section of this manual.

Regulations

All blasting work should be carried out in accordance with local statutes. The wearing of personal protective equipment is mandatory. All blasting equipment should be used in accordance with the manufacturer's specifications.

Pickling Steel Surfaces

Preliminary cleaning

Solvent cleaning (refer PS-601) or alkaline cleaning or mechanical methods (refer PS-602 and PS-603) should be used initially to remove heavy deposits of oil, grease, dirt and other materials not removable by pickling. Weld spatter and slag should also be removed prior to pickling.

Procedure

Millscale, welding scale and rust are removed by chemical reaction, electrolysis, or both, using one of the following pickling methods:

Sulphuric acid pickling
Phosphoric acid pickling
Citric acid pickling
Hydrochloric acid pickling
Alkaline pickling
Electrolytic pickling   — alkaline bath
                                — sea water bath
After pickling, the work should be drained in a way which will minimise entrapment of pickling solution. Do not allow the work to dry out before rinsing.

Rinse by hosing and/or immersing for'/; to 1 minute in a bath of water. Excessive build up of pickling solution in the rinse bath must be avoided.

Passivating additives should be added to the rinse bath, or the second rinse bath if two rinse baths are used. After rinsing, the work should be drained and dried in an oven or by a compressed air blast from which oil and water have been removed. Alternatively, the final rinse may be operated at elevated temperatures.

The paint priming operation should be carried out as soon as the steel is dry, and before leaving the shop.

Safety precautions

The chemicals used in this procedure are corrosive, skin and eye contact must be avoided.

Adequate ventilation should be provided, and operators should wear chemical goggles, rubber aprons, boots and gloves.

Concentrated acid should be added to water or dilute acid very slowly and with continuous stirring. Water should never be added to concentrated acid.

Observe all local and state statutory requirements for effluent disposal, ventilation and safety.

Observe precautions on manufacturer's label.

Warning

Surfaces descaled by chemical treatments are smoother than those produced by abrasive blast cleaning and may cause a reduction in adhesion with some paints. In all cases the paint manufacturer should be consulted in ensure chemically treated surfaces are compatible with the proposed protective system.

Preparation of new wooden surfaces

Procedure

Ensure the wood is thoroughly dry before commencing. If there is any doubt, use a moisture meter to determine the moisture content, which must be less than 15% before painting can commence.

Examine the surface for sap or pitch streaks, grease, oil, etc., and exudations from knots. Scrape off any sap or gum exudations and then treat these areas by solvent cleaning (Refer PS-601).

Using scraper, sandpaper or steel wool, remove dirt and mortar splashes that adhere tightly.

Remove all excessive roughness, loose edges, slivers and splinters with sandpaper.

Precautions

Painting should only be carried out when the temperature is above 10°C, and the relative humidity is less than 85%. The temperature of the surface should be 3°C above the dew point. Do not putty (refer PS-608, Part A), until the primer coat has been applied.

Note: This specification is not intended to cover the surface preparation of floors which are prepared by commercial power floor sanders.

Removal of perished paint by power sanding

Procedure

Remove the bulk of the cracked, flaked, blistered, loose or thick paint by the use of a power sander with a coarse grade of sandpaper on the grinding wheel.

Following coarse sanding, load the power sander with fine sandpaper and 'feather' all edges, rough patches, etc.

Dust down the surface.

Precautions

As the surface being sanded may have been coated with a load paint, it is recommended that the worker should be protected from the generated dust.

Suitable equipment should include complete coverage of all skin and hair and a suitable dust respirator must be worn.

Removal of perished paint by burning off

Procedure

Use suitable equipment capable of giving either a flame, or a blast of intense heat, that will soften the paint film. Hold the flame, or nozzle, at an angle and about 2 centimeters from the surface and about 5 centimeters ahead of the scraper which is used to remove the paint as it bubbles and softens.

Precautions

When wooden surfaces are being burnt off, ensure that the wood is not charred by the flame. Keep the flame away from loose joints, knot holes, cracks and from underside of weather boards.

Ensure no easily ignited materials are concealed on the surface to be burnt off, by thorough inspection of the surface before cleaning commences.

This operation should not be carried out on interior surfaces.
Avoid inhaling noxious fumes. Appropriate respiratory protection should be used.

Do not aim the flame or nozzle at surfaces not to be stripped.

These types of equipment must not be used in any environment where combustible gasses or materials are present.

Removal of perished paint by rapid stripper

Procedure

Using KANSAI Paints Stripper apply a liberal coat of the stripper by brush to the surface of the film to be removed. Allow to stand until the paint is softened and then scrape the paint from the surface.

Repeat the operation until the removal is complete.

Procedure alter removal

Solvent clean the surface in accordance with PS-601, then sand in accordance with PS-607.

Precautions

Avoid contact with skin and eyes and avoid breathing its vapour. Provide adequate ventilation during use. Airflow should be adequate to ensure a comfortable working atmosphere.

Wear rubber gloves and chemical goggles. If swallowed induce vomiting. Obtain medical attention. If skin or eyes are affected wash thoroughly with water.

WARNING: The contents of the can may be under pressure. Release lid with care. "Registered Trademark

Removal of Mould, Grease, Dirt & Gloss from paint and enamel

Removal of Mould and mildew

Procedure

Using a hard brush, remove all loose and powdery deposits from the infected areas. Make a dilute solution of hypochlorite (household bleaches contain hypochlorite) by diluting one part with three parts of clean water.

Apply this diluted solution to the infected areas by swabbing with a clean cloth.

Allow the solution to remain on the surface for 10-20 minutes (depending on intensity of growth) and then rinse off with clean water.

Apply second treatment if necessary.

Allow to dry thoroughly.

Precautions

Observe precautions on the manufacturer's label.

Removal of
Moss and lichen growth

Procedure

Using a hard brush or broom, remove all loose and powdery deposits from the areas exhibiting the growth.
Make up either of the following solutions:
Copper sulphate 20 gram Ammonium carbonate 70 gram Water 1 litre
or
Formalin 200ml Water 800ml
Apply either solution to the surface exhibiting growth and leave for 3-6 days.
Using a hard brush, broom or a mechanical brush, sweep the treated areas and then flush off with copious quantities of clean water. Allow to dry, then treat with hypochlorite in accordance with PS-612.

Precautions

Avoid contact with skin and eyes and avoid breathing its vapour. Provide adequate ventilation during use. Wear rubber gloves and chemical goggles.

If swallowed induce vomiting. Obtain medical attention. If skin contact occurs remove contaminated clothing and wash skin thoroughly. If inhaled remove patient from contaminated area and apply artificial respiration if not breathing.

Removal of
Chalk, dirt and dust

Procedure

Using a stiff bristle brush, dust the surface down. Excessive chalk which remains after this treatment should be removed by scrubbing the surface with a stiff brush using clean water. The surface should then be hosed clean and allowed to dry.

Precautions

Beware of lead paints. Full precautions should be taken with respect to clothing and a dust respirator must be worn when dusting down lead containing paints.

 

Removal of
Grease, dirt and scum

Procedure

Wash down, using either hot or cold water, in which is dissolved soap powder or detergent — or wash the surface with a commercial paint cleaner. This washing should be repeated in the case of extremely dirty surfaces.

After washing the surface, thorough rinsing with clean water should be carried out. The surface should then be allowed to dry.

Precautions

When using commercial paint cleaners, avoid contact with skin and eyes. Wear rubber gloves and' chemical goggles.

 

Removal of Gloss from paint and enamel

Procedure

Make up the following solution:
Trisodium Phosphate 40 gram Water 1 litre. Using the above solution wash the surface down. Then wash down with copious quantities of clean water and allow to dry.

Precautions

Wear rubber gloves and chemical goggles.

Treatment of ‘green’ masonry concrete

Treatment of ‘green’ masonry concrete, stucco, etc.

Procedure

Make up the following solution and stir well:
Zinc chloride 20 gram Phosphoric acid (commercial grade) 30ml Water 1 litre. To the dust free surface apply the solution by brush or mop at a spreading rate not exceeding 1.5m2 per litre. Allow to dry for 48 hours, then lightly dust the surface. Do not rinse with water.

Precautions

Avoid contact with skin and eyes. Wear rubber gloves and chemical goggles. If skin contact occurs remove contaminated clothing and wash skin thoroughly. If splashed in eye, wash out with copious quantities of water and obtain medical attention. If swallowed do not induce vomiting. Give plenty of water or milk and obtain medical attention.

 

Acid etching of efflorescent free concrete surfaces

Procedure

Remove all dust, dirt, etc., from the surface to be treated, then apply a 10% solution of hydrochloric (muriatic) acid by brush or mop, flowing the acid on to the surface. Allow the acid to remain on the surface for approximately 15 minutes and then thoroughly rinse the treated areas with liberal quantities of clean water.

Prepare acid solution by adding 1 part of commercial 32% hydrochloric acid (muriatic acid) to 2 parts by volume of water. Do not add water to acid. Apply at approximately 3 sq. metres per litre.

Precautions

Avoid contact with skin and eyes. Wear rubber gloves and chemical goggles. If skin contact occurs remove contaminated clothing and wash skin thoroughly. If splashed in eye, wash out with copious quantities of water and obtain medical attention. If swallowed do not induce vomiting. Give plenty of water or milk and obtain medical attention.

 

Removal of paint from concrete floors with caustic soda solution

Procedure

Dust the surface down and sweep. Make up the following solution:
Caustic soda (flaked) 150 gram Water 1 litre
Apply the solution to the surface using a suitable mop. Allow to stand for 10-15 minutes, then, using copious quantities of clean water, wash the surface down. Allow to dry.
Note: This method is not suitable for many heavy duty coatings e.g. epoxy and polyurethanes.

Precautions

Strong caustic solutions are highly corrosive and require care in handling. Avoid contact with clothing, eyes and skin. Wear rubber gloves and boots, and chemical goggles.

If skin contact occurs, remove contaminated clothing and wash skin thoroughly. If splashed in eye, wash out with copious quantities of water and obtain medical attention. If swallowed do not induce vomiting. Give plenty of water or milk and obtain medical attention.

Refer to Ihn Health and Safety Aspects page included in the front section of this manual.

 

Removal of surface layer from set plaster surfaces

Procedure

Dust the areas to be treated. Make up the following solution:
Commercial grade phosphoric acid 125 ml
Water 1 litre
Apply by brush or swab liberal quantities of the above solution to the areas to be treated. Allow to dry for 48 hours. Take a strip of adhesive tape and apply to the treated surface. Leave 10 seconds and pull off quickly. Little or no plaster should adhere to the tape.

Precautions

Avoid contact with skin and eyes. Wear rubber gloves and chemical goggles. If skin contact occurs, remove contaminated clothing and wash skin thoroughly. If splashed in eye, wash out with copious quantities of water and obtain medical attention. If swallowed do not induce vomiting. Give plenty of water or milk and obtain medical attention.

Removal of efflorescence from a set plaster surface

Procedure

Wipe the efflorescence from a portion of the surface with a clean, dry rag. Allow the wiped surface to age for a few days, then examine for efflorescence. If present, wipe down again and re-examine again after a few days. Continue this operation until efflorescence ceases. Make up the following solution:
Calcium chloride (commercial grade -35%      solution) 1 litre
Water 3 litres
Dust the entire surface down and apply the solution to the dusted surface. Allow to dry for 48 hours. Do not wipe down after drying.

Precautions

A paint film will not stop efflorescence if it is still active. It is essential to ensure that the efflorescing action has ceased prior to painting.
When using Calcium Chloride solution eye and skin contact must be avoided.