December '20

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5 4 G R A P H I C S P R O D E C E M B E R 2 0 2 0 G R A P H I C S - P R O. C O M I n most of my articles, I have covered the more glamorous topics of glass blanks, equipment, photoresists, and such, and it occurred to me that the most basic of the materials used in our line of work goes largely unmen- tioned: abrasives. I want to fix this over- sight with this article; after all, where would we be without it? GENERAL INFORMATION Etching abrasives are particles of hard, granular material that have sharp corners and edges. They are hard enough and sharp enough to erode glass and other materials if they are directed at the surface at high speed. When they hit the surface, they cause small chips to be broken out of the surface. Over a period of time, the abrasive can erode down below the surface and actually carve into the material. Some of the choices you are faced with if you etch and carve glass include glass beads, beach sand (brown), white crys- tal silica sand, garnet, aluminum oxide (white, brown, or pink), and silicon car- bide (black or green). These materials vary in price from less than $4 per 100 pounds to over $200 per 100 pounds. When you consider that in a given blasting job you may use as much as 50 to 100 pounds or more in an hour, it becomes obvious that you need a little more information before making your purchasing decision. The best abrasives to use are the ones that are the hardest and have the sharpest, longest lasting corners and edges on the particles. However, those are also the most expensive. In order to make them worth- while to use, you have to be able to recap- ture and reuse them over and over. In re- cycling the more expensive abrasives, you increase their cost efficiency to the point where they actually cost less to use on a per hour basis than sand or other cheap materials. ABRASIVE TYPES Sand was used for long periods of time, and rumor has it that there are still some indi- viduals out there who use it (for question- able reasons) for architectural-sized work. I often hear that it's because it is cheap. That is certainly true, but only on the surface. Since you can only use sand once in the blasting process because it dulls with use, you constantly have to replace it, which Choosing Your Abrasive HOW YOUR ABRASIVE CHOICES AFFECT THE FINAL SANDCARVED PRODUCT B Y R U T H D O B B I N S Your decision of which abrasive to use depends on the cost effectiveness of each one for the job, your blasting equipment, technique, and use. (Images courtesy Rayzist) PUT IT INTO PRACTICE! TRY THIS SIMPLE SANDCARVING TUTO - RIAL TO CREATE BEAU- TIFUL WINE GLASSES: A W A R D S & C U S T O M I Z AT I O N

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