Friday, 11 January 2013

Process of Acrylics in Jewelry Making

Use an ordinary jeweler's saw or a coping saw to cut sheets of plexiglass.
Different kinds of acrylic materials can be used in jewelry to create light, crisp, and colorful effects. You can make entire pieces from acrylic, or acrylic can be used in combination with metal in ingenious and subtle ways.

You can obtain acrylics from plastics suppliers, or you may live near to a company that makes small plastic articles and that would be happy to pass on scraps to you. If you buy it from a supplier, you will be able to select from sheets, rods or tubes, circles, squares, rectangles, etc., that are clear or colored, transparent or opaque. Acrylic is an easy material to work with, because it can be cut by hand with a jeweler's or coping saw and it can be filed, polished, bent in gentle heat, drilled, carved, or worked on a lathe.

 Acrylic can also be used as a two-part resin, which is poured or "cast" into metal to give a finish that resembles enamel.

If plexiglass sheet is heated gently, it can be bent around a former or pressed into a mold.One problem with acrylic is that, compared with metal, it is very vulnerable, so its use needs to be carefully considered. The surface will scratch easily, and although the scratches can be easily removed, it is not always practicable to do so. 

Cutting 


Acrylic or plexiglass sheets are usually supplied with a paper covering, and you can draw the pattern directly onto the paper before you cut out the design with a jeweler's or coping saw. You should use a no. 0 or no. I blade, or an even coarser one if necessary. Make sure that you catch all the dust and swan f from the acrylic in a clean bag below the bench pin because it is irritating to have acrylic mixed with the metal scrap. As it is cut, acrylic tends to get very hot, which makes swarf melt onto the piercing blade. Cutting slowly should overcome this problem, but if you notice that the acrylic is beginning to cling to the blade, clear it by drawing the edge of a file down each side of the blade. 

Filing and finishing 


 Set the angle of cut on the lathe at 75' and insert a round acrylic rod with a diameter of 5/8 inch into the chuck. Carefully turn a cone shape. Files can get clogged up quickly when they are used to smooth acrylics, and if you are going to use a lot of acrylics, it is worth keeping a separate set of files. You will need a file brush to clean them regularly. Use the files in exactly the same way as you would on metal, removing the marks made by one file with the next size down. You can get a smooth finish by working through the various grades of wet and dry sandpapers and then finishing off with a liquid metal cleaner. You can also use a polishing mop with grease-free white polish, which gives acrylic a shiny, clear surface. You must take care that it does not get too hot or the surface will start to melt and the polish will become a series of dragged black lines. Polish can be removed with detergent. Do not use acetone, turpentine, denatured alcohol, or benzene on acrylic because they can all damage the surface.

An effective way of finishing polished acrylics is to deliberately make them frosty. 

When the cones are cool, peel off the masking fluid and drill a 1/32 inch wide hole approximately 1/4 inch deep in the center of the base of each cone. This can be done with fine steel wool and detergent and water or with a brass brush, used with detergent and held in the flexible shaft machine. A satin or bark finishing brush can also be used on a polishing machine to give a frosty finish. Always wear safety glasses when you use these brushes because loose pieces of steel can fly off when they are in use. 

Drilling and engraving 


Most small holes can be drilled straight through an acrylic sheet or rod, but if you need to make a hole in a very thick sheet, you will need to lift the drill in and out several times so that the acrylic does not get too hot and the swan f does not melt on the drill. The hole will be visible as a white line or, in transparent acrylic, as an opaque line.

Engraving tools can be used on acrylics, but again. the edges of the lines will be opaque unless they can be individually polished. 

Casting


Mix the two parts of acrylic in equal proportions and add the appropriate color. This mix can be poured into metal "cloisons" (compartments) or into a mold. You must pour the liquid resin steadily and slowly. If you pour too quickly, heat can be generated and you may find that air bubbles appear. If you are pouring into metal cloisons, the resin is usually poured so that it is a little higher than the edge of the metal. When it is hard, it can be filed level or rubbed down with wet and dry sandpapers. Any holes that may have appeared after filing can be filled up and allowed to dry before the piece is polished.

 Use contact cement or a two-part adhesive to glue silver wire, cut to about 11/2 inches long, in the hole. Use your pliers to bend the wire into shape. Pouring resin into a mold has to be done in two stages. First, the mold is half-filled and allowed to set before the other half is poured in. If you try to fill the mold at once, you will generate too much heat. You can take advantage of this natural break by changing the color or even by introducing a small object. 

Gluing


 When you glue acrylic pieces together or to another material, you must use a clear, compatible adhesive. Some adhesives can be colored with dye to match the acrylic. 

Thermosetting


Thermosetting is a process whereby acrylics and plastics can be shaped by heat. This can be done in an ordinary oven set at 350°F, over an electric hot plate, or by using a blow torch. When the plastic has reached 350°F, remove it from the heat you must wear thick, protective gloves  and use your hands to bend it around or pour it into a mold. If you use a blow torch, use a gentle flame.
Writer- JINKS McGRATH
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