Blog / Fusing

Luminescent glass is different than iridescent glass. It is low-fire—not high-fire like iridescent—and is intended for reverse fusing.

What is reverse fusing? Reverse fusing means placing your piece face down on the kiln shelf and building backwards, fire-coated side down. If you are firing on a textured mold, place a piece of Thin Fire between your boron-treated mold and the glass. If you fire your piece with the coated side up or cover it with another piece of glass or you will lose the coating. If you are slumping and do not go over 1,200 degrees, you can place the luminescent side up and not lose the coating. Luminescent glass is food-safe and has been tested by the U.S. Food and Drug Administration. However, please note that once the piece has been fired in your kiln, it is no longer a Wissmach product; it is your product. If you have been firing glass that could leave lead or cadmium traces in your kiln, that could get on the product, which would render it unsafe for serving food or beverages. LEFT: Luminescent glass fired with Thin Fire in between, with the coating facedown. RIGHT: Luminescent glass fired facedown, directly on the mold.

Firing Schedules: Courtesy of Petra Kaiser and Wissmach Glass

Standard Fusing Schedule – 2 Layers Thick

Segment 1: 600°F/hr. up to 1,000°F, hold for 10 minutes

Segment 2: Full/9,999 up to 1,410°F, hold for 10 minutes

Segment 3: Full/9,999 down to 950°F, hold for 60 minutes

Segment 4: 100°F down to 700°F, hold for 1 minute

Tack Fuse, Polishing and/or Slumping into a Mold

Segment 1: 300°F/hr. up to 1,000°F, hold for 10 minutes

Segment 2: Full/9,999 up to 1,300°F or 1,350°F (depending on your desired results), hold for 10 minutes

Segment 3: Full/9,999 down to 950°F, hold for 60 minutes

Segment 4: 100°F down to 700°F, hold for 1 minute

Draping over a Mold and/or Polishing

Segment 1: 300°F/hr. up to 1,000°F, hold for 10 minutes Segment 2: Full/9,999 up to 1,200°F or 1,220°F (depending on your desired results), hold for 10 minutes Segment 3: Full/9,999 down to 950°F, hold for 60 minutes Segment 4: 100°F down to 700°F, hold for 1 minute

NOTE: Not all kilns are alike. Your kiln size, controller type and individual project may require some alteration to the schedule for best results.

Iridescent glass is made by Oceanside, Bullseye and Youghiogheny.  Also Wissmach non fusible. When firing it can be placed up or down. This info from Oceanside.

Iridescent glasses have a micro-thin layer of metallic crystal creating a reflective surface that shimmers in rainbow, silver, or gold tones. Because of its metallic nature, the coating has specific characteristics that are important to understand as you plan fused glass projects. 

The metallic coating doesn’t melt so it resists bonding:

If you were to try to fuse two iridized surfaces facing together, they will not bond well, if at all.

When stacking a design on top of an Iridized surface, you may get more of a tack-fused look than you intend. Use this to your advantage to create very dimensional work or adjust your schedule.

To fully clear cap an Iridescent glass, make sure your piece of clear is slightly larger (between 1/8" and 1/4" on all sides) so that it has enough area to bond with the edges of the glass below.

The metallic coating doesn’t stretch:

This is why a crackling effect can be seen when Iridescent glasses are allowed to spread — especially when the irid surface is on top, face-up. Enjoy the look—alternately, dam pieces or construct them using a circular design (where the glass tends to draw inward when full-fused) to minimize the effect. Clear capping produces more of a pinching or crinkling look as the clear presses into the coated surface below.

 

Picture from Angelas Art Glass on Etsy.

The same coating is more dramatic on darker glasses:

The rainbow iridescence on Clear or White is much more subtle and delicate than on darker colors or Black, which is the most dramatic. 

 

Firing for Different Effects:

Irid side down: in this example, the iridescent surface of the glass is placed face down on the kiln shelf paper, with a piece of clear on top. This look can make a lovely matte finish for either the top or bottom of a piece.

Irid side up: in this example, the iridescent surface of the glass is placed face up on top of a piece of clear. This gives the most opportunity for glass to spread and crackle.

Irid side up and capped with clear: in this example, the iridescent surface of the glass is placed face-up and capped with a slightly larger piece of clear glass on top. 

 

 

 

 Using Clear Textured Iridescent Glasses:

Place the texture side down onto a darker base glass. Although the texture will flatten using a full fuse, the irid design from the texture will still be visible with interesting distortions from the texture.  Do small test fires to know.  

In smaller pieces of Iridescent Clear or other light colors, it can be difficult to tell which side has the coating.  Simply scratch both sides with your fingernail--the irid surface will grip more than the smooth side.  

MODELING GLASS

Ever wish you could get more detail on a project? Modeling Clay is the answer. It was developed by Glass Bird Studios. It is a two-part kit that has a powdered binder and liquid medium. It is mixed with water and your own powdered glass or frit. Once it is mixed, it is the consistency of clay and you can work it like clay. It is food safe and non-toxic. You can pretty much do everything with it that you do with clay. Roll it, cut out shapes, put in silicone molds. You can then fire to a tack and get amazing detail. Glass Bird Modeling Glass Starter Kit (stainedglassexpress.com) Lois Manno, the owner and developer of Glass Bird Modeling Glass, is a talented, experienced artist. Her love of nature shows in her artwork. She is most known for her feathers made from Modeling Glass. This incredible image is made by Bob Leatherbarrow, who is one of our industry’s amazing artist and teacher. He created the lines with Modeling Glass. See more of this work at www.leatherbarrowglass.com

FUSING GLASS BOTTLES OR “HIDING THE EVIDENCE” Don’t you just hate to throw out those wine and liquor bottles? They are quite nice with the graceful shapes and the beautiful colors. Make them into fused art! First (and most important) step is to clean them. The labels and any glue must be completely removed to be sure that no residue is fused onto the glass. Use very hot water with ½ cup baking soda and 1 tablespoon of dish soap. Submerge them in the water and let them soak for 10 minutes then add 2 cups of white wine vinegar. Roll your bottles around so the vinegar mixes in. Let them soak until you can get the labels off. Once the bottles are clean you have some options. You can just lay it in the kiln and full fuse it. This one just has a little decorative wiring and some etching. You could add a decorative knife and have a nice little gift. Another option is to use a bottle mold. There are all types available. See the full collection here. There are textured molds. The one above has a lovely Tree of Life motif. Drop molds, such as the one above, make an interesting shape. You also can use a textured flat mold, such as the one below, and then slump it into a bottle mold. You may get devitrification with some bottles. To prevent it, spay with a divit spray like Spray A.

How beautiful is this VASE!? (I FEEL LIKE I COULD JUST POST THE PICTURE AND IT WOULD BE ENOUGH!)

This vase was made c. 1910. It is Aventurine Lava Blown Glass by Tiffany Studios. This is currently on display in the new exhibition at the Morse Museum called “Iridescence—A Celebration”. This vase was among Tiffany’s treasured A-Coll (Artist Collection) pieces exhibited at Laurelton Hall. It is a striking vase and was made by draping lava like aventurine glass over iridescent gold glass. The name aventurine references the quartz-like glass with sparkling particles developed in Murano, Italy around 1910 when this was made. You can use aventurine glass for your treasures also. Available from Bullseye and Oceanside in flat glass and frit. Usually available in black, blue or green. It has been a little tough to get lately but we have some. Click here to order.

Q: When I fuse my projects, sometimes I get medium to small bubbles. What causes them and how can I prevent them? A: Bubbles can be caused by many different things. First, uneven stacking of glass can result in air trapped between layers. To prevent this from occurring, check the placement of all the glass pieces and insure they are sitting properly on the base. Since the edges of the glass fuse before the center of the glass, cut your base glass 1/8” larger than the top layer to allow air to escape. Second, check the glass prior to fusing. Some glass may already have contained bubbles inside the glass, which may or may not affect the outcome. Q: After I fuse my pendants, I get uneven areas around the edges. What’s happening with the glass? A: You did not fire it long enough or to a high enough temperature for a full fuse. Try firing for a little longer time. Q: Sometimes my glass pieces look like a porcupine with spiky edges. What causes the glass to spike? A: Spiky edges can be caused by over-firing your piece. The spiked edges are caused by the glass grabbing as it is trying to shrink. Q: What caused my layered glass pieces to flatten? A: If the glass piece has flattened out too much, you have over fired the piece. To prevent this from happening, reduce your power and shorten your time. After your first firing, open the microwave and using Fireworks Hot Mitts™; carefully lift the lid to inspect the fuse piece. If the desired results have not been achieved, continue firing in 30 seconds intervals. Q: I tried to make a 1 inch pendant with embellishments, however after I finished fusing, the glass shrunk. How can I prevent this from happening the next time? A: Glass naturally wants to be ¼ inch thick when heated. Your glass will shrink or expand to obtain this depth. A good tip to remember is that if your piece is less than ¼ inch when you start, it will shrink up to reach this depth. If your piece is larger than ¼ inch when you start, it will want to flatten out to reach this depth. Q: What causes two pieces of dichroic or iridized glass to blow apart in the kiln? A: Repelling glass will occur with dichroic and iridized coatings. The coatings can’t be placed together for fusing purposes, because they repel each other. The only way to avoid this is to encase the coated glass with a non-coated glass, such as clear. This will cause the coated glass to be encased and sealed. Q: Yuck, this film appeared on my fused glass. What is it and how can I prevent this from happening? A: This dull white crystalline substance on the surface of your glass is known as devitrification. This is one of the most talked about glass fusing problems around. It can occur when your glass remains in a temperature range 1000ºF-1300ºF too long. You need to minimize the time spent in this temperature range. Gray or Scummy Edges - Gray or scummy edges can occur on pieces that have been fired once and then cold worked before refiring. Cold working involves using either a grinder or glass saw on a piece of glass. These can be avoided by thoroughly cleaning the glass before refiring the piece. Keep a bowl of clean water near your work area and soak the glass right after doing the cold work procedure. This will keep the edges damp and allow the piece to be cleaned easier. Scrub completely and let dry before proceeding with the refiring process. Q: My glass cracked! What happened? A: Cracking glass either during or after firing can be caused by a several things: thermal shock, heating up the glass too fast and compatibility. Thermal shock occurs either by taking the piece out of the kiln too soon, or by opening the kiln and exposing the hot glass to cool air. If the glass cracked in the kiln and it has an “S” shaped crack, the piece has heated too quickly. Slow down! Finally, if the crack occurs along the line where the two pieces of glass meet, then the two touching pieces are not compatible. Make sure the glass you are using have the same COE (coefficient of expansion). Q: How can I prevent my glass from shattering? A: Glass Shattering in pieces over 1” with more than 1 layer may sometimes shatter. To prevent this from occurring, reduce the power. This will allow the glass to heat slower and will be less likely to shatter. Next, make sure your glass is clean and dry before firing. Q: My fusing instructions say to clean my glass before firing, can I use a glass cleaning spray or detergent? A: We don’t recommend it. Detergents, dish soaps, multi-purpose cleaners, some window cleaners, ammonia and even denatured alcohol should NOT be used to clean glass. These can actually promote devitrification. We suggest diluted white vinegar or rinsing your glass with distilled water. Q: Every time I put my fuse glass project together, the pieces roll off before I can get it to the microwave. What can I do to prevent this from happening? A: To hold your fusing project together, mix one drop of glue. Apply a very thin amount on the back of the glass using a brush and allow the glue to dry thoroughly before firing.