Luminar Moldable Sheet Type LMS, is an advanced material for glass slumping and fusing. No other mold material is as strong, light, versatile, durable, and easy to use. LMS has the ability to become pliable while wetted with water and regain its original strength when dried. Thus when it is given a shape when wet; it will retain that form when dry. LMS comes as a semi-rigid sheet and is available in four thicknesses: 20, 40, 80, and 120 thousandths of an inch. LMS 20 has the least strength and highest moldability. LMS 120 has the highest strength and least moldability. On firing, a small amount of organic binder burns out and ceramic strength is developed. A fired LMS mold will have about 3 times the strength of unfired LMS. Once fired LMS losses its ability to be molded when wet. LMS is immune to thermal shock, and since it is very light, LMS has been proven to allow firing rates of 130° F/min in a stationary studio kiln with 1/8" glass. This manual will describe methods of preparing and using LMS molds.

Selection of the best thickness of LMS to use is mostly a matter of balancing the strength of a given thickness of LMS to the degree of curvature to be developed in the final piece.

When attempting to take a plane surface such as a sheet of LMS and form it to a curved surface, such as a deeply bent lamp element, you will observe that a certain amount of "puckering" or folding will result. This is because the curved surface has apparently less surface area than the plane surface we started with. This effect is more pronounced when using thicker LMS because the difference in the radius between the inner and outer surfaces of the LMS is greater. Using the thinnest necessary thickness of LMS will minimize any difficulty.

In the event that folds are unavoidable, excess material may be cut away much as a seamstress would cut a "dart". Methods of cutting LMS are given below. When wetted the LMS may be firmly squeezed and held together at the seam to result in a firm bond on drying. The seam can be dressed by burnishing with a damp cellulose sponge. If necessary, irregularity may be corrected using LUMINAR Mold Mix 6 to build up and smooth the seam.

LMS may be cut with a utility or exacto knife either wet or dry; although cutting is generally easier when the material is wet.

After the desired shape is cut, the LMS is ready to be immersed in water. Use a shallow tray of warm water. The piece should be fully submerged. The table below gives soak times for the different thicknesses of LMS.

Test for flexibility. The moistened sheet should feel like wet leather. If the sheet is not flexible enough, apply more water. If the sheet is overly moist, blot up excess water with a paper towel. Any unused wet sheet can be dried and stored flat for re-use.

LMS will bond quite firmly to most surfaces, even glass. To assure removal from the pattern, a very thin coat of "Vaseline" should be applied. Once the LMS is laid on the pattern, it must be held firmly against it in order to accurately replicate its contours. Clothespins around the edges generally work well to hold the LMS in place.

LMS may be left alone to air dry, although it is often desirable to accelerate drying. This is easily done be warming to 200° F in the kiln. Take care that the pattern you use will be able to withstand heating. Once dried, the LMS regains its original rigidity.

Prior to firing, it is often desirable to finish the surface of the LMS mold. This is easily done using a damp cellulose sponge or finger. The LMS surface may be burnished with either of these until it shines. If the mold is to be used for fusing, give it a coat of ALUMACOAT to avoid sticking. This step must be repeated each time the mold is fired for fusing.

No special precautions are necessary to fire an LMS mold. As mentioned, the firing can proceed at very rapid rates with no difficulty. However, in the event that the glass is fairly heavy, it will be desirable to pre-fire the mold. This will develop its ceramic strength before it is loaded with glass, thus reducing the possibility of firing in some deformity as a result of the weight. Once an LMS mold is fired, it can be wetted and shaped again.

LMS may be used as a fusing surface for most glass commonly used with the exception of "Wasser Glass" which has pronounced tendency to adhere to LMS. It is critical that the surface of LMS be treated with a coat of ALUMACOAT each time the LMS shelf is fired if adhesion is to be avoided.

Application with a nylon brush is best. Should the surface require dressing after application of the ALUMACOAT, a damp sponge may be used to gently smooth the surface.

Fire the LMS to fusing temperature no faster than 15° F/min. on a flat ceramic kiln shelf prior to use for fusing. The slow firing will avoid warpage and develop the ceramic strength of the LMS.

It is best to fashion a shelf support of LMS for the LMS shelf to retain the advantages of LMS’s low mass or use LUMINAR Fusing Sheet strong kiln shelf.

LUMINAR Fusing Sheet, is an alumina composite material, heat treated to enhance mechanical and thermal properties. It is lightweight, has a porous surface, smooth on both sides and allows for rapid heating and cooling cycles. The LFS can be fired repeatedly (its tan color will turn white on first firing) and can be cut to the desired size with a hacksaw or other common tools. To prevent warping or slumping of the sheet when firing heavy loads, some support should be provided from below.

A light coat of ALUMACOAT diluted with equal parts water should be applied with a nylon brush prior to each firing. Depending on the glass and firing schedule, some sticking may occur. Testing of the sheet is recommended before firing a major piece. Should sticking occur, a sheet of LUMINAR Ceramic Paper (LCP), may be placed on the LUMINAR Fusing Sheet to act as a parting agent. Any fibers adhering to the fired glass can be easily removed by rubbing with a sponge or finger.

Molds may be made from a wide variety of objects, known as patterns. A pattern is the original object from which all replicas are made. Patterns may be made from plastic materials such as plasticene or clay, or they may be made of rigid materials like wood or plaster. There are many good books on pattern making and the type you choose to use with Mold Mix 6 is a matter of personal preference. For a pattern to work well with Mold Mix 6, it must have no porosity. This means that patterns of wood or plaster must be sealed, preferably with shellac. Paints will work, but the film thickness of most paints will obscure fine surface detail. Unfired clay is the least successful of all pattern materials, as it will leave a residue in the mold. Waxes are excellent for use with Mold Mix 6 as pattern materials and require no special preparation. While anything may be modeled readily in waxes, the lost wax process is their highest usefulness.

Mold Mix 6 will adhere quite firmly to surfaces, which have not been treated with a parting agent. Several common parting agents have been shown to work well. The first is PAM, a parting agent usually used in the kitchen. It must be applied sparingly as it will ruin the mold surface in heavy applications. Others are petroleum jelly, which in thin application gives good results as well as a light coat of dish soap.

After the pattern has been prepared and given a coat of parting agent, it is ready for application of Mold Mix 6. Initially, a thin coat of Mold Mix 6, which has been diluted 35wt.% with water, should be applied with a supple nylon brush. The first coat with diluted material will assure that all fine detail is resolved. Drying of the Mold Mix 6 should be complete between coats. Drying may be accelerated by uniform heating or with an appropriate pattern a microwave oven may be used. After the first coat is dry, build up the mold with undiluted Mold Mix 6 to a thickness appropriate to the size of the work. 3/8" to 5/8" is usually sufficient.