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What materials are used for etching?

Resists

Hand cut resists
The primary materials you need for etching are resists and abrasive. There are many types of resists, and the ones you use should be picked for the job at hand. If you hand cut your own resists, pick a self adhesive vinyl or rubber blasting resist that is made especially for glass. That means the resist will hold tightly while you are blasting but release cleanly, with no adhesive residue left on the glass when you remove it after etching.

A thickness of 4-6 mils is good for surface etching or shading, 8-25 mils thick for deep carving. (A mil is a thousandth of an inch.) The higher the pressure you want to use and the faster you want to carve, the thicker the resist should be. These resists are usually available in rolls from 18" to 36" wide and 10 to 50 yards long. They always come with a silicone release backing paper to protect the adhesive until you are ready to apply the resist. Resists especially made for glass are somewhat difficult to find, but some etching equipment manufacturers and glass etching suppliers carry them.

Pre-cut resists & photo resists
It is much easier to use pre-cut resists or photo resists, because they already have a design produced and cut out on them. This gives you perfect results, no matter how many times you do the same design, and doesnít require that you enlarge and hand cut your own designs. Pre-cut and photo resists can produce designs of very high complexity with very little work on your part. You can use the designs offered by the stencil companies (like EtchMaster) that make these resists or you can send your own designs to be made up for you. For more information on these resists and a selection of patterns and designs, see the section on Stencils, under the Learn glass etching portion of this site.

Abrasives

In order to etch glass, an abrasive has to be as hard or harder than the glass and the particles have to be rough, with sharp corners and edges. Glass beads donít work well at all, since the beads are round and smooth. Sand works, since it is the same hardness as glass (glass is primarily made of sand) and the particles are rough, but there are three major problems.

First, the sand dust from blasting is very hazardous to breathe, and can potentially cause silicosis, a fatal lung disease. If you use sand, you always have to wear a very good respirator and replace the cartridges regularly. Second, sand particles dull quickly, so they canít be reused many times. This means you have to spend more money on replacing sand. Third, you can't get sand in a fine grit. The smallest particle size you can generally get with sand is about a 90 grit. Most etching these days is done with grit sizes of 120, 150 or finer, to give a beautiful, smooth finish to the etching. For awards and gifts, 180 to 220 is common. (The higher the number, the finer the grit.)

The best abrasive you can use is silicon carbide. While glass is rated between 4.5 and 6 on the Mohs hardness scale (depending on what type of glass), silicon carbide is a 9.5 (on a scale of 10, with 10 being diamond). It is reusable until the particles pulverize small enough to be sucked out of the system as dust. It is a little more expensive than aluminum oxide (the second choice) but not if you consider the cost per hour to use carbide, rather than the cost per pound. Oxide is 9 on the Mohs scale, so it cuts fairly fast, but creates a lot of static electricity in the cabinet, which will constantly cause static shocks. In addition, the dust clings tenaciously to the back of the glass, making it difficult to see exactly what you are etching. This is very distracting when you are trying to use the shading technique.

The dust from both silicon carbide and aluminum oxide are considered to be "nuisance dusts" rather than a hazardous material as sand is, so they are both safer than using sand. Since both materials cost less than 80 cents per hour to use, carbide is the professional's choice for etching glass.