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Abrasive Blasting Guide | Abrasive | Aluminium Oxide

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Abrasive Blasting Guide Abrasive blasting will produce an effect that may combine both a cleaning and finishing action. The finishing effect may vary by controlling such factors as hardness of the abrasive, abrasive particle size, velocity of abrasive stream, angle of abrasive gun, distance from the work, method of application and work flow. As it is applied to preparation of surfaces prior to finishing, abrasive blasting is generally used to replace sanding, wire brushing and pickling. Ordinar
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  Abrasive Blasting Guide Abrasive blasting will produce an effect that may combine both a cleaning and finishing action.The finishing effect may vary by controlling such factors as hardness of the abrasive, abrasiveparticle size, velocity of abrasive stream, angle of abrasive gun, distance from the work, methodof application and work flow.As it is applied to preparation of surfaces prior to finishing, abrasive blasting is generally used toreplace sanding, wire brushing and pickling. Ordinarily, no other cleaning is necessary becausethe blasted surface is chemically and mechanically cleaned.Abrasive blasting can save from 25% to 75% of the time normally required by hand cleaning.Blasting is considered economical. The abrasives are relatively inexpensive and reusable. Thegeneral economical advantages of abrasive blasting lie in the reduction of man-hours required toclean and finish parts and needing only minimally trained personnel, yet still having highproductivity per hour per dollar of equipment.Abrasive blasting can make a good finish better and cleaner. It also produces a better tooth forbonding. It is estimated that the surface area of metal increases as much as ten times as a result of the abrasive impact action. This increases the surface to which paint, coating or plating canadhere.PressureDirect pressure machines require less pressure. Whereas a siphon machine is normally operatedat 60-90 PSI, the direct pressure machines can function at 15-80 PSI. Operating at lower pressurereduces the work hardening of the surface and reduces warping of thin parts.Most people sandblast at an air pressure that is too high. When you blast at pressures above 90PSI, there is an excessive breakdown of the media and very little improvement of the cuttingrate.The Sandblast GunAbrasive blasting is supposed to be a scrubbing action, not a peening process. Therefore, the gunshould always be aimed at a 60° to 45° angle to the surface being cleaned. When the gun isaimed at 90°, peening occurs and, due to the abrasive particles colliding with the abrasivebouncing off the surface, a very high rate of media wear occurs.The gun in a siphon machine should be kept at least six inches from the surface being blasted.This allows the spray to spread out and cover a larger area. Blasting a larger circle allows forbetter overlap of the pattern and yields a more even and appealing finish. The direct pressureunits can effectively operate at distances of one foot or more.   The Gun NozzleNozzles made of tungsten carbide are the best choice. Settling for a less expensive, lower qualitynozzle ultimately increases operational costs. If your compressor cannot keep up with the blaster,chose a smaller nozzle for the gun. If you have plenty of pressure at the gauge, but don't seem tofeel it at the gun, look for an obstruction in the abrasive pickup line or something stuck in thenozzle.In a siphon machine, remember to change the air jet (behind the nozzle) every few nozzlechanges. A worn air jet will deflect the flow in the gun and cause the abrasive to wear a hole inthe side of the gun. If you have enough pressure at the gun, but very poor flow of abrasive, yournozzle is worn, there is a hole in the siphon tube pick-up hose, or the abrasive is so fine that itwon't flow down to the pickup area.The HoseReplace the siphon hose on a regular basis. When the walls get too thin the hose will collapseand obstruct the flow.MediaMany types of finish may be obtained by the selection of abrasive and by the adjustment of airpressure in the blasting unit. The more commonly used abrasives are    aluminum oxide,     white aluminum oxide,     urea and other plastic abrasives,     corn cob grit,     walnut shell grit,     glass beads,     pumice,     crushed glass grit,     silicon carbide,     steel grit and    steel shot. For the most efficient performance, when the abrasive in the machine has broken down toomuch, the entire load should be replaced. Adding new material to the old load greatly reduces theperformance of the abrasive and increases the amount of dust.If you are getting a sporadic flow of abrasive, it is being caused by fine material not flowingdown to the pick-up area or too much pressure. Banging on the side of the cabinet hopper cantest this. If the flow is good after this, your material is too fine or may be moist.  MEDIA HINTS    Glass beads can be used to texturize, descale, or remove light burrs and die-cast flashleaving a smooth bright satin finish. Used at 40 to 80 PSI.    Abrasive grits can be used for more aggressive work leaving a dull satin finish and areuseful for creating a good surface for bonding. Use up to 120 PSI.    Walnut shell grit can be used for deflashing thermoset plastics without destroying thesrcinal polish. Use 30 to 80 PSI.GroundingBlasting machines occasionally cause shocks from static electricity. If the operator stands on amat grounded to the machine and the gun is grounded to the cabinet, this will be eliminated. Thecabinet can also be grounded to any conduit for insurance.The WindowTry not to hold a part up to the window. This will cause frosting of the window and make itdifficult to see inside.A scrap surcharge variance is in effect at the time of shipment. Please call for the currentsurcharge. Learn more about the Steel Scrap Surcharge >>  Packaged in 5 lb jars, 10 lb jars, 25 lb pails, 50 lb pails, 55 lb bags & 55 gal drums.Super sacks are also available upon request.Glass beads are manufactured from lead-free, soda lime-type glass, containing no free silica thatis made into preformed ball shapes. Glass beads produce a much smoother and brighter finishthan angular abrasives. Glass beads can be recycled approximately 30 times. Chemically inertand environmentally friendly, glass beads are an acceptable method of metal cleaning or surfacefinishing when properly controlled.Glass Bead BlastingGlass bead blasting produces a clean, bright, satin finish, without dimensional change of theparts. Available in a wide range of sizes, glass beads are primarily used in blasting cabinets forhoning, polishing, peening, blending, finishing, removing light burrs and cleaning most lightforeign matter. For delicate thin-walled parts and thin welds, peening with glass bead abrasivematerial provides the right balance of stress relief without over-stressing and causing damage.Consider the size of perforations or holes through which the glass beads must pass when screenseparating parts from media after use. Size Description Mesh #3 Extra Coarse 20/30#4 #4 Grade 30/40  #5 #5 Grade 40/50#6 Coarse 50/70#8 Medium 70/100#10 Medium-Fine 100/170#13 Fine 170/325Glass bead blasting media is packaged in 50 lb, 25 lb, 10 lb and 5 lb packages. Aluminum Oxide is a sharp, long-lasting abrasive sandblasting cutting media that can be re-used manytimes for grit blasting. As an abrasive blasting media, it is harder than most common dry abrasive blastmedia and will cut even the hardest metals and surfaces. This particular abrasive blasting media comesin a wide range of sizes.White Aluminum Oxide is a 99.5% ultra-pure grade of blasting media. White Aluminum Oxide isincreasingly being used in critical, high performance processes such as microdermabrasion. WhiteAluminum Oxide is also required where contamination from other metal oxides must be kept to aminimum.Corn Cob is a biodegradable blast media that will not etch or warp surface being blasted. Ideal forapplications such as wood log homes and thin metals and plastics.Crushed Glass Grit is a silica-free consumable abrasive that offers aggressive surface profiling and
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