RAINING DIVISION. Equipment Selection for the Painting Contractor

Transcription

1 RAINING DIVISION Equipment Selection for the Painting Contractor 1. THE APPLICATION: Assuming that a spray process is selected as the best method for the application of a coating, then the selection of the proper equipment must be considered. Spray equipment components can be assembled into systems capable of satisfying the needs and requirements of virtually any type of coating application. The selection of these components should be based upon the answer to the question, What exactly do I want to accomplish? To help in answering this question consider the following: A. THE PURPOSE OF THE APPLICATION: 1. Decorative-The spray application of coatings for the prime purpose of improving the appearance of the object. Multiple layers of the coating material will also result in giving protection to the surface to some degree, but this benefit is secondary. Usually the coatings in this field are fairly thin or low in viscosity and require fine atomization. Example: lacquers, stains, varnishes, enamels, and interior house paints. 2. Protective-The application of a coating which has been designed primarily for the protection of the surface. The surface appearance may be improved by this application but this is considered secondary. Protective coatings are usually in the range of medium to heavy viscosity, and fine atomization is generally not required and cannot be achieved when the coating is applied over a rough surface. Examples of these types of coatings are: exterior house paint, coal tar epoxy, fire retardant coatings, plastisoles, vinyls, alkyds, block fillers. B. NATURE OF THE MATERIAL: The coating material required should be selected from a reputable material supplier and the following characteristics or nature of the coating must be considered: 1. The consistency, or viscosity. Is the material very thin, medium or thick? How does it flow? 2. The nature of the material. Is it abrasive, adhesive, or catalyzed? What is its cure rate? Does it require agitation or any special handling considerations? 3. Regardless of whether the material is standard or non-standard, always follow the supplier s recommendations for preparation and application of materials. C. THE MATERIAL VOLUME: The amount of material required to do the job and the size of the container in which the material is purchased will indicate the type of equipment that will be required to apply the material. 1. A small job: When the paint is purchased in quart or gallon size containers and the application rate would not exceed five gallons total per day. Example: spray finishing an individual furniture piece, the basement of a home, kitchen cabinets, or other small individual applications. 2. A medium job: When the paint is purchased in five-gallon containers and the application rate would not exceed 30 gallons per day. Example: the spray painting of homes, farm buildings, small industrial plants. 3. Large job: When paint is purchased in 55 gallon drums and consumption exceeds 30 gallons per day. Example: the painting of bridges, large storage tanks, or large industrial buildings. 55 GAL.

2 2 D. THE APPLICATION RATE: The size, complexity, and cost of equipment varies directly with the size of the job and the application rate: Large jobs, high volume, and fast application require large equipment. II. EQUIPMENT REQUIRED: Spray equipment can be classified into several different types. In many instances one type of equipment can be used to perform many functions. A thorough working knowledge of these classifications will help in making the proper selection. A. TYPE OF EQUIPMENT: 1. Air atomization-material is delivered to the spray gun by either siphon or pressure feed. Jets of compressed air are then introduced at the front end of the spray gun to tear the material apart into small droplets and impart direction and velocity to these droplets. This action can take place either outside the air nozzle (external mix) or inside the air nozzle (internal mix). Siphon spraying (external mix) is best suited for limited production with light, finishing type material where fine atomization and low cost is required. It is ideal also for applications where small amounts of relatively thin materials are required. Pressure feed spraying (external mix) is best suited to applications requiring medium to large quantities of finishing type materials that require extra fine atomization. Pressure feed spraying (internal mix) is best when using maintenance or protective coatings where super fine atomization is not required, such as spraying over rough surfaces where minimum overspray and rebound are desired. Internal mix is also ideal when small quantities of air are available and large areas must be covered. 2. Airless Spray: (Hydraulic Spraying)-Uses a specially designed paint pump to deliver paint to the airless spray gun under relative high pressure. The fluid is then released through a small nozzle orifice. The resulting high fluid velocity causes the material to be torn apart or atomized. Airless spraying is best suited to applications where medium to large areas are to be covered with maintenance coatings or where high film builds and flow rates are required. Airless spraying is the fastest means of applying a coating and will also produce less rebound when the equipment is set correctly and the proper spray techniques are used. 3. Air-assisted airless-in an air-assisted airless (or air/airless) system, a fluid pump delivers coating material, at pressures ranging from 150 to 800 psi, to a spray gun containing an airless tip. The airless tip pre-atomizes the coating, creating a dense, slowmoving pattern with very little overspray. A small amount of compressed air (5 to 20 psi) is introduced to shape, soften, and complete the atomization. The result is a well-formed, finely atomized pattern with a minimum of overspray. 8. FLUID SUPPLY: Siphon Pressure Electric Cup Tank Airless The equipment necessary to supply fluid to the spray gun will be determined by the amount of material you must apply in a given period of time. When materials are purchased in quart or gallon cans, your fluid supply could be a siphon cup, pressure cup, or small pressure tank. When material is bought in five gallon cans, you could use medium size pressure tanks or a small pumping system. When the material is purchased in 55 gallon drum quantities, large pressure tanks or pumping systems will be required. Air controls should be used on pressure tanks and airless pumps to control the fluid pressure. When using internal mix nozzles, two air regulators on the pressure tanks is a must, because these nozzles require approximately equal air and fluid pressure at the spray gun. When material requires agitation/or filtration, accessory equipment is available for these purposes. C. AIR COMPRESSOR: The air compressor is the most important part of any. compressed air operated spray system. The air compressor is the heart of the system because it is the energy source by which the system operates. The most important specification of a compressor is the volume of air that the compressor will deliver per minute (CFM). Unfortunately, many people think that the pressure (PSI) is the most important factor, but this is incorrect. The more CFM s, (or volume of air available), the larger the type of air nozzle that can be used or the bigger the airless pump that can be run. The amount of CFM air available will determine the amount of material that can be properly atomized in a given period of time, and the speed of the application. Note: A 1 H.P. compressor using an electric motor will produce approximately 4 CFM at 100 PSI. Using this rule of thumb enables one to calculate the amount of air that is available from a compressor. A gasoline powered compressor requires about 2 HP. to produce approximately 4 CFM at 100 PSI. When working with portable compressors, remember that a 1.5 H.P. electric unit is maximum for most house outlets. When more air volume is required it is advisable to consider a gasoline powered unit. Air regulators should be provided to control the flow of air to the spray equipment. If possible, filters and oil and water extractors should be employed to insure clean, dirt free air. This will minimize finish contamination, pump freezing and lengthens the life of air operated equipment.

3 D. HOSE AND FITTINGS: The proper size hose and fittings are important in conveying the air and fluid to the spray gun. Selection should be made so that the pressure loss in the system remains at a minimum by using the proper connections and a hose with a large enough inside diameter. When selecting hoses consider the following: 1. The volume of air or fluid the hose must carry. 2. The working pressure of the system. 3. The viscosity of the fluid. 4. The temperature of the fluid. 5. The type of material and solvents that are going to pass through the hose. 6. The length of the hose required. Air-assisted airless spray guns: are designed for spraying paints and coatings utilizing the air/airless method. The fluid is delivered to the spray gun at low airless pressures (150 to 800 psi) where it is pre-atomized in an airless tip. Atomization is completed by introducing compressed air at low pressure to the airless pattern. The result is a finely atomized pattern that produces a finish that closely resembles the high-quality finish obtainable with air atomization. Special purpose spray guns: are designed to perform certain specialized applications, e.g. blow guns, dusting guns, car washing spray guns, flow guns, flock guns, solvent guns, and glitter guns. E. TYPE OF SPRAY GUN: Spray guns are selected according to their function and where they are going to be used. The nozzles used on spray guns are selected according to the type of material that is going to be sprayed and the amount of material to be atomized in a given time. The more volume of air the nozzle requires, the faster the material can be atomized or the finer the atomization will be. With airless tips the larger the nozzletip orifice (Hole) the faster the material can be applied. The wider the angle of the tip the greater the area which can be covered with each pass of the spray gun. Remember that one must have sufficient air volume available or a pump large enough to supply the material demand of the fluid nozzle or airless tip. 1. Heavy-duty production spray guns: are built of the finest materials, and include many design features not available in lighter weight equipment. They are designed to be used under heavy production conditions and are built to provide day to day reliability. 2. High volume low pressure spray guns: are used for full production operation. They atomize coatings with high volume low pressure air to comply with EPA regulations in many areas. Higher transfer efficiency also. 3. Touch-up spray guns: provide a smaller spray pattern and are used for coating small objects, shading and toning of furniture and because of their light weight, are preferred by many women spray operators. They use less air than production spray guns, however they still produce the same type finish as the larger type but require more time for the application. 4. Heavy fluid spray guns: are used to apply heavy viscosity materials under production conditions, e.g. asphalt coatings, texture finishes, drywall surfaces, and block fillers. 5. Lightweight (small application type) spray guns: are intended for use with small portable air compressors, small applications required by the home owner or small contractor. They are capable of producing a fine finish, however at a much slower speed than the production spray guns. Model 115 Model Airless spray guns: are designed to withstand the high pressures required in the airless atomization method and provide a means of turning the fluid on and off. Fluid flow is controlled by the proper selection of the airless tips, by their orifice and angle. F. SAFETY EQUIPMENT: The type of safety equipment required for the protection of the spray operator and others in the area is most important. However, the most important factor is common sense. This equipment includes face respirators, chemical respirators, hood respirators, and air masks.

4 Ill. SPRAY EQUIPMENT SELECTION: A thorough knowledge of each component that makes up a systern should be reviewed. This may be accomplished by referring to training division bulletins covering the various parts that make up each system. 1. The size of job 2. Material purchased in 3. Required by 4. Type equipment (spraying process) 5. Compressed air supply 6. Fluid supply equipment 7. Hose and fittings 8. Spray gun type 9. Safety equipment FOR DECORATIVE AND PROTECTIVE APPLICATIONS Small One gallon cans Homeowner. small contractor, (sprays occasionally) Air atomization (external or internal mix) l/4 H.P. to 1 H.P. electric drive (hand carried units, minimum regulation and filtration equipment) Siphon and pressure cups, two gallon tanks (equipment with regulators) 1/4 to 3/8 I.D. hose (standard type connections) Lightweight small application type. touch-up Filter type respirator A. CONSIDERATION GUIDE: AS an aid in selecting the best possible equipment for your partitular application the following chart should be reviewed and the equipment check list filled out. Medium Five gallon cans Medium size contractor (regularly spraying small to medium areas) Air or airless (external or intemal mix) 1.5 H.P. to 10 H.P. gas or electric (portable on wheels with air receivers, air regulators and extractors Siphon and pressure cups, medium size tanks, small airless systems. (Equipped with controls, agitators, filters and regulators) 5/16 to 1/2 I.D. hose (standard type connections quick change fittings) Standard production airless special purpose as required Filter type, chemical type, or hood type respirators Large Fifty-five gallon drum Large contractors (sprays large areas) Air or airless (external, internal mix, heated, electrostatic) 10 H.P. and up, diesel or gas (skid or trailer mounted) air controls and moisture traps Pressure tanks, large airless systems, low pressure pumps (all accessories fully equipped) 5/16 to 1 1/2% I.D. (all types and size hose and fittings, adapters, nipples and valves) Heavy-duty standard type, heavy fluid touch-up, special type as required All types of respirators, protective clothing, and barrier creams 10. Approximate cost of outfits $300 to $600 $600 to $3,000 $3,000 and up B. TYPICAL BASIC EQUIPMENT LAYOUTS: The units listed below and other items are the minimum needs that one could anticipate requiring when considering the various size jobs one would undertake. 1. SMALL SIZE JOBS: Compressed air supply.... Model l/3 H.P. Compressor Model Metering Valve Fluid supply... Model Siphon Cup Hose and fittings... Model Air Hose (5/16 in. I.D. x 25 ft. length w/l/4 NPS connections) Spray gun Model 370A Gun with a (87 X 87F) nozzle set up Safety equipment.... Model Respirator, cartridge type Model Model Model

5 2. MEDIUM SIZE JOBS: Compressed air supply Model Low Boy 1.5 HP Model Oil and Water Extractor Model Metering Valve AIR ATOMIZATION Fluid supply.. Model Siphon Cup Model Pressure Tank (2-gal.) Hose and fittings... Model Air Hose (3/8 in. I.D. x 25 ft. length w/1/4 NPS connections) Model Air Hose (5/16 in. I.D. x 25 ft. length w/1/4 NPS connections) Model Fluid Hose (3/8 in. I.D. x 25 ft. length w/3/8 NPS connections) Spray gun.. Model 2001 Gun with one of the following nozzle set-ups: Siphon feed, external mix (66 x 66S) Pressure feed, external mix (63C x 63P) Pressure feed, internal mix (66SS x 204) Model Model Model Fluid supply. Hose and fittings... Spray gun.... Safety equipment.... AIRLESS ATOMIZATION. Model Comet 4B Pump, 30: 1 ratio, 1 GPM, complete outfit Model Super BEE electric airless pump, complete outfit Model Air Hose (3/8 in. I.D. x 25 ft. length w/1/4 NPS connections) Model Fluid Hose, high pressure (l/4 in I.D. x 25 ft. length w/1/4 NPS connection) Model Fluid Hose, high pressure (l/4 in. I.D. x 50 ft. length w/l/4 NPS connection) Model Nipple (l/4 NPS x l/4 NPS).. Model Airless 1 with the following tips: Model for narrow angle work up to 8" spray pattern Model for medium size work up to 14" spray pattern Model for large areas up to 18" spray pattern. Model Respirator, cartridge type Model

6 3. LARGE SIZE JOBS: Compressed air supply. Model Compressor Filter Oil and Water Extractor Model Metering Valve AIR ATOMIZATION Fluid supply Model Pressure Tank 10 gals.) for conventional materials Model Pump for heavy material, complete texture Outfit Model In-line Strainer for light materials Model Funnel Strainer for light materials Hose and fittings. Model Air Hose (3/4 in. I.D. x 50 ft. length w/3/4 NPS connections) Model Air Hose (l/2 in. I.D. x 50 ft. length w/l/2 NPS connections) Model Air Hose (3/8 in. I.D. x 25 ft. length w/1/4 NPS connections) Model Air Hose (5/16 in. I.D. x 25 ft. length w/1/4 NPS connections) Model Fluid Hose (3/8 in. I.D. x 25 ft. length w/3/8 NPS connections) Model Fluid Hose (3/4 in. I.D. x 25 ft. length w/3/4 NPS connections) Model Nipple (314 NPS x 1/2 NPS) Model Adapter (1/2 NPS x 3/8 NPS) Model Adapter (3/8 NPS x 1/4 NPS) Model Nipple (3/8 NPS x 3/8 NPS) Model Swivel for heavy materials gun Spray gun..... Model 2001 Gun with one of the following nozzle set-ups: Pressure feed, external mix (63C x 63PB) Pressure feed, internal mix (67SS x 206) AIRLESS ATOMIZATION Fluid supply.. Model B5-18 Pump, 29:1 Ratio, 1.8 GPM, complete outfit Spray gun.... Model Airless 1 (see page 5 for list of tips) Model 42A Pole Gun 6 ft. long with the following tips: Model for narrow angle work up to a 10-inch spray pattern Model for medium size work up to a 15-inch spray pattern Model for large areas work up to a 2l-inch spray pattern Safety equipment Model Respirator, cartridge type Model Hood Respirator Comet 3C S.S. Model 2001 Model

7 C. EQUIPMENT CHECK LIST: As each part is considered in making up a complete system the following check list should be filled out. The catalogs listed will provide specific features and model numbers. Prices can be obtained by consulting the price list for equipment. CONSIDERATIONS 1. PURPOSE OF THE APPLICATION:. Decorative Protective Other 2. FLUID CHARACTERISTICS:.. Type of material Viscosity: Thin Medium Thick Nature of the material: Abrasives Corrosive Special handling considerations are: 3. PAINT IS PURCHASED IN:... Ones Fives Fifty fives Other 4. TYPE OF EQUIPMENT: Air Atomization: ~ External mix Internal mix ~ Airless Atomization Heated Electrostatic SELECTION SPRAY GUN TYPE: Air atomization (Catalog A54-19) Heavy-duty production - Standard Production - Touch-up - Heavy fluids - Lightweight (Homeowner) - Bleeder -or Non-bleeder Airless and Air-Assisted Airless atomization Production Touch-up Heated Heavy fluid Special type Pole gun -Flow gun -Flock gun -Dust gun - Other types Model number selected Nozzle Set-up CFM required Accessory items Nozzle extensions Circulating connections Swivel connections Strainer connections Other items Model numbers selected COMPRESSED AIR SUPPLY Actual CFM Required PSI (Catalog AC) Compressor horsepower - Portable -Stationary Electric -G a s - Single Stage -Two stage Model number selected Accessory Items: - Extractors -Air regulators - Lubricators Other Items Model numbers FLUID SUPPLY Siphon cup - Pressure cup - Pressure tank - Size required - (Catalog A98-29) Model number selected Low pressure pump High pressure pump Gallons required per minute Pressure required R a t i o - Circulating system - Non-circulating Corrosion resistance required Abrasion resistance Model Number Accessories: Air control Pulsation chamber Filter Screen size Fluid regulator Agitator Inner container or liner Off-set strainer funnel Other items Model numbers selected

8 SELECTION (continued) HOSE AND FITTINGS Air Hose: CFM - Inside Diameter ~L e n g t h ~ (Catalog A ) Maximum working pressure Model numbers selected Fluid hose: GPM Viscosity: Light - Medium Heavy Length Inside Diameter Solvent resistance: Yes No Model numbers selected: Connections Thread style: NPT - NPS - Male Female - Size Type Connections: Removable - Punch Lock - Electrostatic Nylon retract Synflex Airless Other Quantity and model numbers selected Accessory items: - Nipples Adapters - Swivel Connection Valves -Quick Disconnects Others Specify type thread style and size Model numbers and quantities SAFETY EQUIPMENT Filter respirators Chemical cartridge type Hood (Catalog A ) respirators Self contained breathing equipment Protective clothing - Barrier creams - Safety glasses Other considerations Model numbers selected IV. GETTING THE MOST FROM YOUR EQUIPMENT: To get the most from your spray painting system it must be controlled. Remember that spray equipment can t think for itself, it will only obey you and the laws of physics. This is the reason why people should be trained to use this equipment so maximum benefits can be realized. A. CONTROLS: Spray equipment will work only if you control it. The following list of control points should be considered. 1. Viscosity-is controlled by the addition or deletion of heat or solvents. 2. Fluid flow rate-controlled by the selection of the proper size fluid nozzle orifice and using the lowest possible pressure required to give you the fluid you need. 3. Atomizing pressure when the spray pattern is right; the pressure is right provided that the lowest pressure necessary is used. 4. Overspray and rebound is controlled by using the lowest possible pressure necessary to do the job. B. MAINTENANCE: Always follow the equipment manufacturers instructions to the letter for maintaining the equipment you have. Try and clean the equipment as soon as the job is completed before the material has a chance to set up. C. ACCESSORIES: Accessory items are sometimes a necessary part of the system and enable you to receive maximum benefit from your investment. Some of the importan! accessories are: Air regulators for control of the operating pressures in the system. Air and fluid filters for the removal of contaminants. Blow guns to clean equipment and the surface prior to spray painting, minimizing dirt contamination in the final finish. Agitators to minimize material handling cost and insure uniformity of mix. Pole guns to extend your reach into those areas you would like to reach. Quick change detachable connections for ease of equipment changeover and for simplifying maintenance. Printed in 12/92 Binks Manufacturing Company 9201 Belmont Ave., Franklin Park, IL *Telephone (708)