REUSABLE MOLDS FOR CASTING

Always start the same way: Clean surface. If it is the first time ZYP your Colour de Verre box lid and has been applied to the mold, it is base with a stiff, nylon brush or a necessary to apply a second coat green 3M Scotch-Brite™ pad to of the product. remove any old kiln wash. (This step can be skipped if the mold is brand new.) There are two choices for primers: Hotline Primo™ Primer and ZYP B N L u b r i c o at ™ ( fo r m e rl y Box Basics MR-97). The ZYP is the easiest to This project sheet provides the apply and remove. It is an aerosol reader with all the basics – fill and, after firing, brushes off easily weights, schedules, and tech- from the molds and can be washed niques – for using Colour de off the glass pieces. Castings cre- Verre’s box base and lid casting ated using ZYP have exceptionally molds. The resulting pieces can smooth surfaces and almost never “stand alone” or can be embell- Before applying the second coat, require grinding or “cold work.” ished with other Colour de let the mold dry for five minutes. Verre designs. When applying or removing either Apply the second coat using an- nnn of these two primers, it is advis- other four to five-second burst of able to wear a dust mask. Bullseye spray. Repeat this process with the highly recommends using ZYP lid mold using a two to three-sec- Each design consists of two molds. Primer for this box mold. ond burst of spray. One mold – the larger of the two Let the molds dry for ten to fifteen – is used to cast the box base. The minutes before filling. Again, the other mold; the lid. double coat of ZYP only need be For a successful casting, there are applied the first time the molds are three important steps to remem- used. Thereafter, only one coat is ber: necessary. For more information about ZYP, visit the Colour de • Prime the mold correctly. Verre website. • Heat the molds no faster than Filling the Molds 300ºF (165ºC) per hour. The molds are intended to be used • Don’t rush the To apply ZYP, work in a well ven- with . Colour de Verre schedule. The controlled cool- tilated area or outside, and hold molds should not be used with ing of the kiln prevents inter- the well-shaken can 10 to 12 inch- borosilicate, Pyrex, crushed nal stresses from cracking the es from the base mold. Hold both bottles, or float glass. At the piece. the mold and the spray can up- temperatures necessary to melt the right. Apply the first coat using a later glass formulations, the kiln Getting Started three to four-second burst of spray wash starts loosing its effectiveness. The two molds must be primed so in a sweeping pattern across all the the glass doesn’t adhere. mold’s cavities. Do not saturate the REUSABLE MOLDS FOR GLASS CASTING

The designs can be filled with any design’s center. Fine frit produces schedule’s slow cooling ramp as frit size, billets, extra large frit, fewer spurs than larger frit or cut this allows for proper annealing. sheet glass – broken or cut-to-fit, sheet glass. Spurs can be ground Also note that the schedules may “nipped” rods, or a combination and the pieces fire polished. Using need to be modified for kiln load, of these forms. ZYP Primer, casting spurs are type of glass, and glass color. eliminated or greatly reduced. Heating element position can also For larger glass formats like billets effect firings. Use lower tempera- and extra large frit, we suggest that For projects where different types of glass is combined, it is often tures when using a lid element the “hold” at the maximum kiln. temperature be increased to give easier to weigh the glass in the the glass a chance to conform to mold. the mold rather than increasing Place an empty mold on the scale, the target temperature. zero the scale, and fill the mold The table below lists how much directly stopping when the fill glass (in grams) should be weight is reached. arranged in each design’s base and When arranging larger glass frit lid. We often refer to these weights or pieces in the molds, as “fill weights.” load and arrange the glass gently Place a container on the digital as the sharp edges can scrape scale. Zero the scale and measure away the kiln wash or ZYP from out the frit for the base. If your the mold. This could contaminate Another factor is whether the glass scale doesn’t have a zero or tare the glass or cause the casting to is or transparent. It is always stick. a good idea to “cut” your opal Fill Weights in grams Firing the Molds glass by mixing it with 50% or Design Base Lid Place the two filled molds into the more clear or transparent glass. 3½” Round 295 115 kiln. Use the Casting Schedule be- For opal glass, reduce firing tem- 4x5” Rectangle 450 220 low as a guide. Don’t rush the perature by 25ºF (15ºC) and use 6” Elliptical 375 180 5” Kidney 385 180 Casting Schedule* 3½” Heart 310 130 Segment Ramp Temperature Hold 1 300ºF/165ºC 1250ºF/675ºC 30 minutes function, simply account for the 300ºF/165ºC 1435-1445ºF/780-785ºC 30-60 minutes container’s weight in your mea- 2 surements. With a second contain- 3 AFAP 900ºF/482ºC 90 minutes er, repeat the process weighing out 4 50ºF/30ºC 800ºF/425ºC None enough frit for the design’s lid. 5 100ºF/60ºC 600ºF/315ºC Off. No venting Carefully pour the weighed glass Fire Polish Schedule* into the primed molds. When cast- Segment Ramp Temperature Hold ing, glass spurs can be formed as 200ºF/110ºC 1325-1350ºF/720-730ºC 10-20 minutes the hot glass melts and compacts 1 and then drags down the mold’s 2 AFAP 900ºF/482ºC 90 minutes interior. To reduce or eliminate 3 50ºF/30ºC 800ºF/425ºC None spurs, mound the glass towards the 4 100ºF/60ºC 600ºF/315ºC Off. No venting * Schedule for Bullseye Glass. AFAP means “As Fast As Possible”, no venting. REUSABLE MOLDS FOR GLASS CASTING

place the cast, glass base into the castings, frit balls, slumped rods, kiln without its mold, right side up, streamers, and stringers. on a kiln shelf protected by Thin- Place the lid in a freshly-primed Fire or kiln wash. Follow the High mold. (This prevents the lid from Gloss Firing Schedule. warping.) Arrange the glass ele- This firing is designed to melt the ments on the lid. A drop or two of piece’s outer surface without soft- GlasTac can be used to tem- ening the piece’s core and causing porarily hold the piece in place. If it to loose shape. Remember that the elements have been slumped shorter hold times. Opal glass has darker and opalescent colors ab- or shaped, support the pieces with a tendency to absorb more heat. sorb more energy and will heat wedges of fiber paper. Fire accord- These high, prolonged tempera- faster and hotter. For darker and ing to the Tacking Schedule. opalescent glass, use temperatures tures can make the kiln wash diffi- Base Feet in the lower range of Segment 2. cult to remove from the mold and Give cast boxes a professional fin- For transparent, light, and iridized glass. If this occurs, fine sandpaper ish with the addition of feet. Use glass, use temperatures in the or a dry, non-scratch, nylon, peel-and-stick, silicon cabinet higher range of Segment 2. kitchen scouring pad, e.g. Scotch- bumpers, e.g. 3M Bumpon™, Brite™, can be used to remove Fusing Components To Lids available from Bullseye or a hard- stubborn kiln wash. Boxes can be embellished by tack ware store. This will also protect Fire Polishing fusing elements to the lids. Possi- tabletops. With any casting process, there is a bilities include Colour de Verre chance for glass spurs to develop. If the casting has any spurs, re- move with a power grinder or a diamond pad. Clean and re-prime High Gloss Firing Schedule* the molds, and place the smoothed Segment Ramp Temperature Hold pieces into the freshly primed 1 200ºF/110ºC 1150ºF/620ºC 5 minutes molds. Re-fire the piece according 2 AFAP 1300-1325ºF/705-720ºC None the to Fire Polish Schedule. The 3 AFAP 900ºF/482ºC 90 minutes lid should always be placed back 4 50ºF/30ºC 800ºF/425ºC None in its freshly-primed mold when- ever it is being fire polished or 5 100ºF/60ºC 600ºF/315ºC Off. No venting * Schedule for Bullseye Glass. AFAP means “As Fast As Possible”, no venting. when tack fusing embellishments to it. Tacking Schedule* High Gloss Firing Segment Ramp Temperature Hold Most people like the subtle con- 1 200ºF/110ºC 1250-1275ºF/675-690ºC 5-10 minutes trast between the lid’s high gloss 2 AFAP 900ºF/482ºC 90 minutes surface and the satin surface of the 3 50ºF/30ºC 800ºF/425ºC None base. However, people occasional- 4 100ºF/60ºC 600ºF/315ºC Off. No venting ly wish to have the base’s surface * Schedule for Bullseye Glass. AFAP means “As Fast As Possible”, no venting. perfectly match the lid’s gloss. If you wish to “gloss” the box’s base,