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| Having problems selecting the right gun for you? Is your final product never just quite right? Emissions too high? What, oh what paint, a spray gun or booth should I use? We'll help you answer all of your questions.
Because the majority of manufacturing engineers and paint supervisors
Spray application is not always the most efficient means for getting the coating onto the job. Sometimes a more sophisticated method is called for. One can pick from any of the following:
The most important equipment in any spray painting facility is the spray booth. A properly designed booth is essential to insure that paint overspray or bounce-back is efficiently removed from the area surrounding the unit To assist companies in avoiding such problems, Ron Joseph & Associates consults with clients on spray booths and filtering systems that comprise any of the following combinations: Common Spray Booth Deficiencies This document outlines some basic descriptions of observations made by Ron Joseph over the past 6 years visiting Air Force painting facilities. Click here
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Filtering Media
Direction of Air Flow
Add-On
What does the EPA say about spray booths and filters? The USEPA has written rules that will lower the particulate size of paint particles that can be emitted from the stack of a spray booth. This applies particularly to coatings that contain chromate pigments. Current regulations already specify test methods for determining the efficiency of the filtering system.
Traditionally, most paint failures can be traced back to poor surface preparation. Although degreasing and conversion coating chemicals used to clean and treat the surfaces can be at fault, more often than not it is the process controls that are faulty. Consequently, the consultants at Ron Joseph & Associates have become experts in all of the common liquid and solid cleaning and treating processes. Liquid Cleaning and Pretreatment Processes
Mechanical Cleaning The most common abrasives used in this process include:
When the painting job goes "sour" and the customer won't accept the paint finish, often the last resort is to strip or remove the coating. In large factories, even when the coating finish is excellent, heavy deposits of paints and coatings sometimes collect on conveyor hooks, floor gratings and coating racks. These excess build-ups need to be removed periodically to allow the coating process to continue without causing blemishes in the freshly-applied coatings. Paint stripping (depainting, as it is referred to in the US Air Force) is expensive and one usually hopes to avoid its need. But when stripping is the only alternative, Ron Joseph & Associates recommends and consults on any of the following processes (depending on the circumstances): Liquid Processes
Dry Processes
Throughout the 1980s, and more so in the 1990s, metal fabricators have taken a serious look at powder coatings because of their environmental friendliness Powder coatings are perhaps the fastest growing segment of the coatings industry, and with new low-temperature curing products (250oF, 121oC) now available, one can also expect this coating market to start penetrating the plastics industry. The most common resin systems being used include:
Ron Joseph & Associates also has contacts with the major industry suppliers of powders and powder coating equipment.
Current Low-VOC/Low-HAP coating technologies are specialized and have unique properties. After California became the first state seriously to enforce low-VOC regulations in the early 1980s, these coatings have gradually been introduced into the market. As a result of the 1990 Clean Air Act Amendments, most states now restrict the VOC content of coatings. Ron Joseph & Associates has been involved with these technologies since the inception of the regulations in 1977. Since then, RJA has regularly consulted to both industry and the environmental regulating community on VOC-compliant and low-HAP content, high solids and water-borne primers, topcoats, and conformal coatings, air/force dried or baked (stoved). Differences between Air-Dry, Force-Dry and Baking (stoving) By USEPA definition, coatings air- (force-)dried are those that can cure below 194oF (90oC), while by definition, baked (stoved) coating require temperatures higher than 194oC (90oC) to cure. The VOC limits in most state regulations are higher for air/force-dried coatings than for baked (stoved) coating. For both air pollution and safety reasons, coatings sold today are lead-free and chromate-free. Technologies that are available to meet regulations
It has often been shown that when one makes improvements to a process, or makes the process more efficient, invariably costs Ron Joseph & Associates has studied all aspects of a Paints, Coatings and Solvents operation, from the moment raw materials enter the facility, through the surface preparation and coating application processes, until the finished product is shipped from the shipping dock. As a result of these studies, more than 100 strategies have been developed that will automatically lead to Better Management Practices (BMP) and Pollution Prevention (P2). In 1994, the USEPA contracted RJA to write a 16-chaper manual on pollution prevention opportunities in the Paints, Coatings and Solvents industries. The manual is now available from the Government Printing Office and other US publication agencies: "Pollution Prevention in the Paints and Coatings Industry," USEPA, Office of Research and Development, EPA/625/R-96/003. (Major Research, 1994) As a result of our detailed knowledge in this field, we consult with companies and perform on-site assessments to identify opportunities for minimizing VOC/HAP emissions, use of hazardous materials, hazardous waste disposal and contaminated water discharges.
When coating failures are not obvious, Ron Joseph & Associates relies on RJA has the availability to conduct tests on:
Independent Testing Laboratories
Failure; Coating Material Failure Analysis Over the past 25 years in the coatings industry, Ron Joseph & Associates Consultants have been called on to solve numerous paint failures. Causes have varied, but include one or more of the following:
To determine the causes for failures, we have often had to use paint testing equipment and instruments.
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© 2009 - Ron Joseph, Paint Consultant in Saratoga, California |
being painted. In spray booths that are undersized, poorly lit, or in which the air flow moves in the wrong direction, paint defects invariably occur and must subsequently be remedied. Even when spray booths have adequate brightness, the position of the lights often make it difficult or impossible for the painter to see his "wet edge" as he applies the coating.
. Powder coatings essentially generate zero Volatile Organic Compounds (VOC) and Hazardous Air Pollutants (HAP), and many metal fabricating companies are able to process their work pieces without generating any hazardous waste!
diminish dramatically, and all forms of pollution are immediately reduced. Surprisingly, many of these improvements can be made with little or no capital outlays. It is often simply a matter of breaking bad habits.
laboratory analyses, such as fingerprinting the coating formulation using FTIR, or subjecting samples to GC/MS analyses. More straight forward sleuthing is conducted by subjecting the coating to salt spray (salt fog), QUV condensation weatherometer, UV weatherometer, Xenon-Arc, etc.
