Pacific Spray Booths Pty Ltd have now merged their Blasting / Dust Collection Division with Gortec Abrasive Solutions. Gortec Pty Ltd are a Brisbane based Company whom have been working alongside Pacific Spray Booths Pty Ltd with various projects requiring both “Paint & Blast Solutions”. Gortec Pty Ltd are able to assist us with local & interstate solutions for all of our Clients & we look forward to growing our relationship further into the future. Visit Gortec’s Website: www.gortec.net.au Blast Equipment & Dust Collectors Abrasive blasting has been around for as long as man could throw a mineral abrasive, such as silica sand onto an object. The reasons for the surface preparation vary from removing an existing coating to preparing the surface to accept a new coating. The idea is simple, and the industry was born with the advent of the air compressor. An abrasive blast room is the core to any modern abrasive blast system. Confining the blasting operation to a controlled clean environment enables efficient abrasive recycling. The design criteria required for a properly sized blast room system includes the size of the largest work piece, the weight of the largest work piece, the material handling method, the number of hours of blasting per day, and the base material of the work piece. Each of these items needs to be addressed in order to finalize the configuration of the blast room. The size of the largest piece will determine the dimensions of the blast room enclosure. The width of the room is determined by adding four to five feet on each side of the work piece. This space is required for the blast operator to manoeuvre around the part and blast the part from various angles. The height of the blast room is also determined by the work piece height, but the material handling of the part must also be considered. For example, if a work car on a track is the material handling method, then the height of the work car must be taken into consideration to determine proper clearance of the blast room roof panels. Again, a four- to five-foot clear area will be required for the blast operator or up to seven feet clear if the operator will walk on top of the part while blasting (e.g. a tank in the rail car industry). The length of the blast room is determined by adding four to five feet on each end of the work piece to allow for operator clearance. Ventilating a blast room can be done by three different methods of air-flow design. The three air-flow designs are “down-draft,” “end-to-centre,” and “cross-draft” ventilation. The various room air speeds are determined by the abrasive that will be used in the blast room and the method the room is to be ventilated. Our Systems are Designed & Constructed to meet the criteria set by the Australian Standards – AS-1627.4-2005. The most common and economical method of ventilation is “cross-draft.” Basically, the calculation for the dust collector size is determined by the following formula: width of room x height of room x cross-sectional air speed (fpm) = cfm. Note: The cross sectional air speed is typically 50 fpm for steel grit abrasive and 60 fpm for nonferrous mineral abrasives. For example, the dust collector sizing for a room 16 x 16 x 60 ft. that is using steel grit abrasive is calculated as follows: 16 x 16 ft. x 50 fpm = 12,800 cfm required for a room air-flow rate of 50 fpm. The reclaim system adds an additional air volume to the dust collector that will range between 500 to 1,200 cfm; therefore, the resultant dust collector will be sized for (12,800 cfm + 500 cfm.)—a total of 13,300 cfm. When selecting the proper abrasive for the blast room, it is important to look at the entire spectrum of parts that will be blasted in the facility. For example, a job shop blasting operation may see one type of work for a period of time and another type of fabricated aluminium parts for another period of time. In this type of application, you would want to select a type of abrasive that is applicable to both types of base material, i.e. steel (ferrous) and aluminium (nonferrous), such as garnet, star blast, aluminium oxide, etc. While a mineral abrasive gives you the flexibility to accept a variety of work into your shop, it does break down at a much faster rate than steel grit abrasive. Typically, you can recycle mineral abrasives about three to six times, based on operating pressures at the nozzle and the initial size and hardness of the abrasive. Steel grit abrasive also comes in a variety of sizes and hardness’s. The typical recycle rate for steel grit (G-40) is 150 to 200 times. Again, this can vary based on operating pressure at the nozzle. Disposal costs of spent abrasives are a major factor in abrasive selection. The amount of waste that must be removed is directly related to the recyclability of the specific abrasive and the volume of abrasive that is used. This can result in a large quantity of waste material that must be dealt with in regards to “cost of disposal.” This cost will vary based on the blasting operation and coatings being removed. If lead paint or zinc primer is being removed, the disposal costs can be up to $500 per 55-gallon drum of waste. The return on investment (ROI) for a blast room facility is the key element when making the investment in a blast room facility. Recycling abrasives and minimizing waste disposal costs is the single most important element in achieving a good ROI on the capital purchase. The reclaim system is comprised of a floor reclaim and an abrasive separator. The floor reclaim design can vary from simple “sweep-in” designs to “full” floor reclaims, which recover all the abrasive through a grated floor. Reclaim designs vary based on the manufacturer and type of abrasive that is being … Continue reading Blast Equipment and Dust Collectors