Glossary of Glassworking and Sandcarving Terms

Term Description More Info
AI The .AI file extension is a proprietary file format developed by Adobe Systems for representing single-page vector-based drawings in either the EPS or PDF formats. Example =
Aluminum Oxide Grit or media for blasting. Mohs scale = 9
Bitmap Raster image made up of individual pixels (or dots), each with specific color information. Bitmap images can not be scaled easily without loss of detail and can not be used directy with a vinyl mask cutter. Also a particular 24-BIT raster image file format defined by Microsoft native to the Windows OS. See BMP See Also…
Blast The act of using pressurized grit to abrade the substrates surface.
Blow Out When a piece of your resist decides to lift off and go its own way in the middle of blasting, this is usually accompanied by colorful language.
BMP The BMP (bit mapped) format is used internally in the Microsoft Windows operating system to handle graphics images. These files are typically not compressed resulting in large files. The main advantage of BMP files is their wide acceptance, simplicity, and use in Windows programs. However, they may pose problems for users of other operating systems. Commonly, BMP files are used for Microsoft’s Paint program. Since most BMP files are uncompressed, and BMP’s RLE compression has serious limits [citation needed], the large size of BMP files makes them unsuitable for file transfer. However, Bit Map images are suitable for background images and wallpapers. This is especially true for screen shots. In addition, images from scanners are usually stored in BMP files. Example = filename.bmp
Buttercut A thick rubber resist made by 3M. The term is frequently used by some to indicate any type of soft, easy-to-cut resist. The current 3M product, Scotchbrand No. 507 “Buttercut” Sandblast Stencil is 45 mil thick, is described as “A green rubber sandblast stencil designed for general purpose use during sandblasting.” The adhesive is rubber. (Irene)
CDR Corel Draw native file format. Corel CDR files can contain vector or raster information, or a combination of both. Example = filename.cdr
CFM Cubic Feet per Minute, a measurement of the volume of air produced by a compressor, or the volume of air required or used by a sandblaster.
Compressor Air Compressor is a mechanical machine, normally powered by an electric motor or a gasoline engine, that compresses air that is used to blast with. See Also…
Deadman Valve A type of shut-off valve for a sandblasting nozzle where a seal is placed over the nozzle opening when the deadman handle is released. A deadman valve works fine for sandblasting rust from auto parts but does not lend itself well to sandcarving applications. See Also…
Down Force A setting on a vinyl cutter that controls how much pressure the cutter uses when pushing down with the blade on the vinyl mask material when it cuts the mask.
DPI Dots Per Inch – A printers term that is the number of dots per inch. See Also…
Dust Collector A piece of equipment similar to a shop-vac that connects to your blasting cabinet to remove the dust from the blasting operation.
Exposure Unit A device to expose photo resist masking material to an Ultraviolet light when creating a photo-mask. See Letralite.
Filler A (generally) rubber-based coating used to fill low areas on substrates that also allows for better adhesion of the resist. It is generally applied directly to the cleaned substrate and allowed to dry. The resist is then applied. When blasting is complete, the resist is removed, and the filler must be cleaned from the substrate. It is important to be sure that the filler and the adhesive on the resist that is being used is compatible. Be sure to determine on what the adhesive on the resist is based. If the adhesive and the filler is incompatible, the resist’s adhesive will be eaten away by the filler. To determine this, call the manufacturer of the resist that is being used, and the manufacturer of the filler to confirm they are compatible. (Irene)
Garnet Grit or Media for blasting. Mohs scale = 8 to 9
GIF Graphics Interchange Format – Another of the graphics formats supported by the Web. GIF is an 8-BIT format, meaning it takes 8 BITS to store the color information for a single pixel. 8 Bits per pixel allows the storage of 256 different colors per image. Unlike JPG, the GIF format is a lossless compression technique. GIF is better than JPG for images with only a few distinct colors, such as line drawings, black and white images and small text that is only a few pixels high. With an animation editor, GIF images can be put together for animated images. GIF also supports transparency, where the background color can be set to transparent in order to let the color on the underlying Web page to show through. Example = filename.gif
Grit or Media – The material that goes into the pressure pot and gets blown by air pressure onto the substrate.
Halftone An image made up of different sizes and patterns of tiny dots to simulate a fulltone photograph. Photographs are turned into black and white halftones in order to create a mask for etching. See Also…
Hand Cut A method of cutting a mask resist where the design to be etched is drawn onto the mask and the mask is manually cut with a razor blade or X-Acto knife.
JPG/Jpeg Joint Photographic Experts Group, JPG is another file format for storing raster or photographic images. JPG is a lossy compression technique that is designed to compress color and grayscale continuous-tone images. The information that is discarded in the compression is information that the human eye cannot detect. JPG images are 24 BIT images, meaning it takes 24 BITS of information to store the color information for a single pixel, and support 16.4 million colors and are best suited for photographs and complex graphics. The user typically has to compromise on either the quality of the image or the size of the file. JPG does not work well on line drawings, lettering or simple graphics because there is not a lot of the image that can be thrown out in the lossy process, so the image loses clarity and sharpness. Example = filename.jpg
Laminated Glass Two or more sheets of glass with an inner layer of plastic. When the glass breaks the plastic keeps it intact.
Laser Tape A type of resist that is cut with a laser and then used as resist in sand carving.
Letralite An ultra violet exposure unit for exposing Photo Resist film.
Line Art Line art is any image that consists of distinct straight and curved lines placed against a (usually plain) background, without gradations in shade (darkness) or hue (color) to represent two-dimensional or three-dimensional objects. Line art can use lines of different colors, although line art is usually monochromatic.
LPI Lines per inch (LPI) is a measurement of printing resolution in systems that use a halftone screen. Specifically, it is a measure of how close together the lines in a halftone grid are. Higher LPI indicates greater detail and sharpness. See Also…
Media Or grit – The material that goes into the pressure pot and gets blown by air pressure onto the substrate.
Mesh A screen for sifting grit or media. Mesh sizes range according to size of grit.
Mohs Scale Scale of mineral hardness. Higher numbers equal harder material. Diamond = 10
Moire Effect A grid or repetitive pattern that appears when printing a halftone image at a different scale than the halftone was generated at. See Also…
Multi Stage Multistage is where you blast different areas of your artwork at different times. Meaning that you don’t weed the whole design at once. This is often done with different pressures also, depending on what you want to accomplish. The end result is a more realistic piece of art, with a “relief” effect and shading.
Nozzle A replaceable tip at the end of a sandblasting hose, which controls the diameter and volume of grit sprayed. The smaller the hole the finer the spray and better the detail obtained. Nozzles wear out (holes enlarge) and require replacement. Nozzles are made of ceramic, tungsten and cerbium.
Nuarc A commercial light exposure unit. These were made for the newspaper and magazine printing trade.
PAB Pickard Artistic Blasting. A maker of blasting equipment that some people really like. The PAB gun is a pistol grip type that gives excellent control of the media and directionality of the air/media stream. See Also…
Paint Mask A type of vinyl similar to sign vinyl, often used for making etching masks. The adhesive is not as strong and it is typically less expensive than sign vinyl making it advantagious for glass etching masks. It is not suitable for rock/stone blasting. Paint mask is normally cut with a vinyl cutter (plotter), but can be hand cut.
Paver A concrete block used for walking on. Often used as a blasting substrate.
PDF Portable Document File, an Adobe file. Example = filename.pdf
Photo Resist A photographic process resist that is exposed with an exposure unit, like a Letralite. “Normal” photo resist requires developing by a washout process before applying to the substrate for etching. Some photo resists require glue to adhere the resist to the substrate, some are self-adhesive.
Pinch Valve A type of shut-off valve for a sandblasting nozzle where a spring type clamp is fit around the rubber or plastic hose just behind the nozzle. Clipping the valve closed pinches the hose and stops air and grit flow. See Also…
Plotter A machine driven by computer software that is used to cut resist.
PNG Portable Network Graphics – The third graphics standard supported by the Web (though not supported by all browsers). PNG was developed as a patent-free answer to the GIF format but is also an improvement on the GIF technique. An image in a lossless PNG file can be 5%-25% more compressed than a GIF file of the same image. PNG builds on the idea of transparency in GIF images and allows the control of the degree of transparency, known as opacity. Example = filename.png
Pot See Pressure pot.
PPI Pixels per inch (PPI) or pixel density is a measurement of the resolution of a computer display, related to the size of the display in inches and the total number of pixels in the horizontal and vertical directions. PPI could also broadly describe the resolution, in pixels, of an image to be printed within a specified space. For instance, a 100×100-pixel image that is printed in a 1-inch square could be said to have 100 pixels per inch, regardless of the printer’s DPI capability. Used in this way, the measurement is only meaningful when printing an image. Good quality photographs usually require 300 pixels per inch when printed. It has been observed that the human eye can generally not differentiate detail beyond 300 PPI.
Pressure Pot A type of sand blasting unit where the media is stored in a pressurized container and injected into the air line under pressure. Pressure pots will allow the user to sandblast faster and with more control than when using syphon units. See Also…
PSI Pounds per Square Inch – Refers to air pressure.
Pull List A picture of the cut resist where the individual areas are numbered in the correct sequence for pulling during blasting top achieve a staged blasted design.
Rapid Mask/RM A photographic process resist that doesn’t require washout made by Photobrasive, Duluth MN. See Also…
Raster A type of image composed of individual pixels (or dots), such as the output from a desktop scanner or a digital camera. These are also called a bitmapped image. Typical raster image types include JPG, GIF, BMP and TIF.
Regulator Regulates air pressure to a device. Air compressors are capable of high PSI. Sandcarving is usually done at much lower PSI, so a regulator is used to adjust it. See Also…
Resist Material that is used to resist the abrasive action of the media or grit. It may be cut either by hand, or plotter or made by photographic process.
Resolution Image resolution describes the detail an image holds. The term applies equally to digital images, film images, and other types of images. Higher resolution means more image detail. Image resolution can be measured in various ways. Basically, resolution quantifies how close lines can be to each other and still be visibly resolved. Resolution units can be tied to physical sizes (e.g. lines per mm, lines per inch) or to the overall size of a picture.
Safety Glass A strengthened or reinforced glass that is less prone to breakage. See Laminated Glass, and Tempered Glass.
Shading Using different PSI and technique, used to vary the amount of grit there by allowing different amounts of frost on the substrate.
SiC/Silicon Carbide Grit or Media for blasting. It is one of the hardest abrasives and unlike aluminum oxide, it will always produce new cutting edges when it breaks down. Mohs scale = 9.5
Silica Sand Silica Sand is the least expensive abrasive material. It is commonly used where reclaiming the abrasive is not feasible such as in unconfined abrasive blasting operations. It has a high breakdown rate which can result in a dusting problem. The dusting problem limits the sand’s use in abrasive cabinets and rooms due to reduced visibility in these enclosures. It is not recommended because of the high incidence of silicosis.
Silicosis Silicosis is a respiratory disease caused by inhalation of silica dust, which leads to inflammation and scarring of the lung tissue. See Also…
Single Stage Blasting A style of etching where a mask is applied to the substrate and the entire image is etched at the same time, usually just frosted.
Single Stage Compressor A type of compressor where the air is compressed by a single cylinder in the compressor. Single stage compressors typically will not compress air as high (PSI) as a Two Stage compressor nor will they recover as quickly.
Siphon System A siphon sandblasting system uses the air pressure and a venturi effect to create a vacuum inside the gun which sucks the grit up into the air stream. This type of equipment is less expensive than a pressure pot. However there are a number of drawbacks. Hence most sandcarvers use a pressure pot. A siphon gun isn’t as powerful. While surface etching isn’t a problem, deep carving, or stage carving would take a long time. You also cannot operate at lower PSI’s like you can with a pressure pot. This is important for shading. See Also…
Squeegee A plastic tool used with vinyl to apply the vinyl or photo mask to the substrate and remove wrinkles and air bubbles.
Substrate That which is getting blasted; i.e. glass, rock, metal.
Supplied Air This is a fresh air system to allow the user to blast in an open environment and not be breathing the dust created from blasting. It involves a clean air supply to either a hood which covers the whole head or a half mask respirator which covers the mouth and nose. See Also…
Tempered Glass Glass that is strengthened by reheating it to just below the melting point and then suddenly cooling it. When this glass breaks it crumbles into small pieces, rather than shards that will easily cut. Approximately 5 times stronger than standard annealed glass; it is required as safety glazing in patio doors, entrance doors, side lights, and other hazardous locations. It cannot be recut after tempering.
TIFF A format for raster or bitmap images. Stands for Tagged Image format File. Example – filename.tiff
Trace To vectorize a rastor image by drawing over the top of the raster pixels with vectors.
Transfer Tape A light adhesive tape that goes down on top of the cut resist to keep the design intact while it is transfered to the substrate. Then the transfer tape is removed and the design is weeded.
Trigger Jet Sprayer Nozzle The TriggerJet Spray Nozzle is a light-weight, non-powered, adjustable spray nozzleIt is a trademarked product sold by Photobrasive Systems and is used for washing out photoresist. It is attached to a hose and uses a fan spray of water at the equivalent of 150 psi (10 bar). It is not as powerful as a pressure washer, but is an excellent substitute. The cost of the nozzle on 3/07 is approximately $25 (Irene)
Two Stage Blasting The process of etching different portions of the substrate to different depths, thereby giving the finished image more definition and detail. Typically done by etching through a mask relatively deep into the substrate, and then removing certain portions of the mask and etching again to a lesser depth or just frost the newly exposed surfaces.
Two Stage Compressor Air compressor, where there are two pistons, one compresses the air into the second one which boosts the PSI even more. Two stage compressors typically will pump to higher pressures (PSI) and recover faster than Single Stage compressors.
Union A type of plumbing fitting used to connect two like typed fittings.
Vector As opposed to the raster image formats where the data describes the characteristics of each individual pixel, vector image formats contain a mathematical geometric description of lines, circles, and bezier curves. Vector images are easily scalable without loosing quality. Vinyl cutters require vector images to cut a mask. See Also…
Vectorize The process of converting a bitmap (or raster) image into a vector image. See also Trace
Vellum A thin translucent parchment type paper used with a laser or inkjet printer to make a type of film-positive image for exposing a photo mask with an exposure unit such as a Letralite.
Washout The process of developing an exposed photo resist mask with a water hose and nozzle to spray the mask with warm water.
Water Separator A piece of small equipment that goes into the air pressure line coming from the air compressor that traps any water in the air stream. Very important, moist grit doesn’t flow very well. Most people have more than one as it’s cheap insurance.
Weed From a cut resist, either hand cut or plotter cut, pull out sections that you want blasted. Sometimes done while blasting to achieve stage blasting.

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