How to Create Fused Glass Pieces - A manual for novices

Since writing is in my blood, I began to collect notes on how I learnt varying aspects of glass fusing, starting with the most basic, glass cutting. I especially took note of those areas where I had problems or trouble finding information. What I am writing is not meant to replace a complete book on the how-to’s of glass fusing, but to go through the steps as I did them in the hope that these will make it easier for someone else.

Since I am an artists as well as having come from a family with scientists among them, I guess I inherited a keen interest in the scientific properties of materials. Thus, one will find reference to various properties of glass, heat, etc. in this book as well. Also, and I cannot stress this enough, one has to have control over one’s tools in any media. This takes PRACTICE. And I mean hours of practice on scoring, cutting, grinding, etc. When one starts working with the kiln and actually fusing pieces, one should get to know the properties of the glass and the properties of the kiln one has.

My first project was to use the glass cutter or scorer correctly. The idea is to score the glass so that it can be broken. The sound that the cutter should make is a hiss. I found a pistol grip cutter worked best. The pistol grip cutter is covered with a cozy for easy gripping.

 

The next picture shows the position I found worked for me. Notice the three arrows. The red arrow shows the position of my right fore finger over the screw on the blade since the blade is a swivel head. This gives me more control. The blue arrow shows my left thumb used as a guide. I found that I did not hold the blade at an exact right angle as described in many of the books. Notice the gold angled line.

 

However, in the beginning, I was not satisfied with my scores. While I could do a straight freehand lines uniformly, my curves were not uniform and I was bearing down too heavily. I could tell when a score would work by the sound. If the sound was not uniform, on this particular type of glass, it did not break uniformly. To make it more uniform, I pressed harder, and of course that did not work. I found I was working too low. When I raised my table’s surface to 34” from the ground (I am 5’2”), my scoring was much improved. Also, I purchased a ceiling tile for under $3.00 from a lumber yard. The reverse side of this makes an excellent surface. You can see the reverse side in the picture of the Toyo Thomas cutter pictured below.

 

I also tried a different tool called a Toyo Thomas. For some work, I found the shape was more conducive to scoring a line without bearing down on it excessively.

 

This next picture shows how the tool is held.

 

While I did not find scoring the glass freeform hard, I found when I followed a line I would freeze up and bear down on the tool too much and change the angle. I weaned myself from this problem by making a score mark on a scrap piece of glass and then keeping the angle constant and moving to the glass I needed to score. In a short time, I didn’t need to do this at all.

After one scores the line, one breaks it. Pictured below are a few different breaking tools one can use.

   

The Breaker-Grozer Combo tool is used with the square/flat side up as a breaking pliers. The tip of the tool is placed on the glass line.

 

The swivel end pliers have a round rubber surface on one lip with a raised dot in the middle. This side is place under the glass with the dot placed on the line. Then the jaws are squeezed together gently on each end of the red dotted line until the glass breaks on the line. The glass will give a little swishing sound when it cracks on either end and a hairline crack will appear, but it will not usually extend from one end to the other. It usually takes about two applications for the glass to break although it can take more.

   

The Running pliers are positioned with the jaws over the end of the glass. Notice how the width of the jaws extends over the glass. However the line on top must be aligned with the line on the glass that needs to be scored. The screw which is always on top is used for adjusting for the thickness of the glass. It is used in a similar manner as the swivel end pliers in that one goes from side to side (from A to B) until the glass fully breaks. See the picture above.

 

Once the glass is cut, the Breaking-Grozing pliers can be used to nibble off any jagged areas. This time, the pliers are positioned with the curved side up. And one just sort of snips or nibbles away at the glass to even out any areas that weren’t cut correctly. The picture shows the piers on their side, but one can notice the curved end.

 

Also notice the squared off edges on the piece of glass. Those are what need to be nibbled off in small bites.

After practicing on window glass, I switched to bullseye glass. Initially, my scores were not strong enough. I do not know whether the glass is actually harder than window glass, but it does take more pressure to score it. I had to readjust how I used the glass cutting (scoring) tools.

To be more creative in my work, I purchased a GlasStar SuperStar II grinder and a Taurus II.2 diamond saw made by Gemini. The latter comes with an accessory kit, which I purchased later. I, also, purchased a separating saw blade so that I could saw interior circles once a hole had been drilled. The diamond saw blade is unique because it is round with diamond chips encircling the core blade. One cuts using all sides of the blade and only moves the work forward and back and sideways. The glass never needs to be turned. I chose this method because I have broken too many blades sawing plastic or wood when I have had to turn my work. The only down feature is the blade is about 1/16 + thick and it removes a larger amount of glass than do more conventional saws. The trick I found to cutting accurate pieces was to not look at the blade but at the line. I remembered when I first learnt to drive a car, I was told to look at the road and not at the steering wheel. I found the same principle applied. Also, to mark the glass so it doesn’t wear off use a white pen, white out, or anything else indelible, and cover it with a very, very thin coating of Vaseline. The dealer, from whom I bought the saw, taught me this trick. I, also, found that using lip palmade and keeping it in the refrigerator worked very well.

Be gentle with the saw and the glass. The blade will break if pushed or tugged, and it is expensive. Barely move the piece of glass as you saw it. A blade can last many months even until the diamond chips wear out.

Soon after I began using the saw, I purchased the accessory kit, mainly for the green light that can be attached to the saw to shine on the work. I found this very useful. However, I soon moved it to use on another tool.

 

The standard bits that come with the grinder can create little nicks on the edge of glass, so I purchased a finer bit and I either use the coarser one first or I solely use the finer bit. Once fired, I have not noticed any edges that have not fire polished completely smooth. As one part of the bit becomes used, one can position it higher or lower on the spindle to use a new area. These bits last a long time. Both the grinder and diamond saw use water as a lubricant to keep the glass and blades or bits cool.

 

I had read about problems people had after grinding or sawing with edges having a whitish look or film because these processes created a matte finish as well as had loose glass adhering to the glass edges. I, then, read that if you immediately put the pieces in a bath of water with detergent in it and scrubbed the edges with a stiff tooth brush or nail brush, the loose glass will be removed and the problem should go away. Following this advice, I have had very few problems with my edges. I keep a dish with dish washer detergent in it and a scrubbing brush.

I’ll jump next to firing in my glass kiln. I researched different kilns and decided on the Skutt GM 814. The size was right, it had a digital controller, and it was 240 volts which was good because we could use the outlet that had been used for my ceramic kiln. It had side and top heating elements. My first project was to make sure the kiln heated evenly, the times were correct and the temperature was correct also. I cut out five 2” squares of clear glass and put a blue 1” square on top. I then placed four on the shelf and one in the middle after cleaning them in dishwashing liquid and hot water and then being careful to not touch the surfaces again.

I firstly, used the pre-programmed program for tack fusing at medium speed and made sure the times, temperatures, and rates were correct. Time equals temperature change divided by rate of change. Using these figures I could set up a theoretical condition and check to see if the kiln lived up to it. For example for segment 1, if the degree change per hour was 305 and the temperature was 350 and the degree change per hour and temperature for segment 2 were respectively 720 and 925, it should take 45 minutes to go from segment 1 to segment 2.

I wanted to set up a schedule that was specific for Bullseye glass. That meant I had to know certain key temperatures. The company has many documents on its website listing the characteristics of its glass, as do all the other glass companies. I recommend downloading all of the information

The following temperatures are the air temperatures in the kiln. From what I have gathered, these are the temperatures that are used . The glass temperatures for fused glass are 50 degrees Fahrenheit lower in the ramp up cycle and 50 degrees Fahrenheit higher in the ramp down cycle. I also knew my kiln read 15 degrees F lower in both the up and down ramp cycles from the Fluke Thermocouple Test Thermometer which is a fairly expensive testing instrument owned by my husbands whose field is electronics.

I made a number of test runs in the kiln using a 2” x 2” piece of glass with a 1” x 1” piece on top to try to fully fuse these two 1/8 inch pieces of glass. None were successful. I got both devitrification as well as needles on the back side of the larger piece. I could not seem to correct either problem. I did discover by searching on http://www.warmglass.com that needling could result from using a single 1/8” piece of glass as a base or from fusing too hot. It was at this point that I decided to try a schedule that followed recommendations by Bullseye for their glass and the information above. While Bullseye gave recommendations, parts were very specific and parts were very general. This is understandable because every kiln is different. And one has to find what works for themselves. I did not truly believe this until faced with the situation.

I put in three test samples. One had only one 1/8” 2”x 2” layer and the other two had two 2”x 2” layers. On each piece were a few smaller pieces. Once fired using this schedule, even the piece with the 1/8” base did not have needles only slightly rough edges and there were no signs of devitrification. If you look at the schedule you will see that 1) I went through the devitrification span as quickly as possible, and 2) I went slowly through the whole annealing range on the downward ramp.

Even though it took 32 minutes to go from 1500 degrees to 1050 degrees, it was only in the dangerous zone 10 minutes. This is without flash venting which is now considered by many in the field to be hard on the kiln and not necessary.

For small pieces of jewelry where I have varying layers from ¼ inch to ½ inch of glass, I use the above as my basic firing guide. I change segment 4, both the temperature and the hold times to change the level or degree of fusing. For example, to not fuse it completely, I would change the temperature to 1480 and the hold time to 10 minutes. Thus I vary those two temperatures and times anywhere between 10 and 15 minutes and 1470 and 1500 degrees Fahrenheit.

To create a piece, everyone has to develop their own routine. I’ll share mine as an example. I sketch ideas for pieces as they come to me. When I want to work on a design, I take the idea to graph paper. This helps align all dimensions. I, then cut it out and trace around it on a piece of oak tag taken from an old file folder.  

1 - Trace around the design on the piece of glass using a non-water base white paint pen. White works well on all colors but very light ones. Let dry a few minutes. Then coat it with a thin layer of Vaseline so the coating will not wash away when cutting and grinding. A little will wash away any how. If the Vaseline is refrigerated, it will protect the line on the glass better.

2 - Using the saw, cut out the design.

3 - Immediately after, put in a dish with the dishwasher detergent and scrub the edges with a toothbrush. Then, put the piece in clear water and let it sit.

4 - If heavy grinding needs to be done, use the standard grinding head . This is the one that probably came with the grinder. I prefer to use a fine head and take longer to grind because I find it is easier on the surface of the glass. Wash the piece according to the directions in the third step. (See # 3.)

5 - Assemble all the pieces. If holes have to be drilled, use a diamond drill. I made a water bath for my drill press which I use with my flexible shaft. I took a tray with a piece of Plexiglas with holes in it and set the Plexiglas in the tray. I, then, filled the tray with just enough water to cover the piece of glass and about ½ inch of the drill bit. I, also, can use this set up for grinding small and hard to reach areas of a piece of glass. I purchased an assortment of diamond drill bits in different grits at a bead show. When I drill a hole, I usually use a thin bit with a grit of 80 or 150 and, then, progress to a finer grit, a 240 or 400. When I want to grind a small area, I usually use a bit with a grit of 240 or a 400. The basic setup is pictured below. Although not evident in this picture, the green light from the Taurus saw now resides on this tool.

 

6 - To assemble the pieces, I use a little bit of glue. I originally used Hotlines, Pate-de-Verre and Fusers Glue only because I happened to buy it. There are others on the market. A few drops goes a long way. This glue does fire completely away even when some remains on the surface of the glass. However, all of these fuser’s glues are very thin and take a long time to dry. I will discuss glues after section 7.

7 - The pieces are then ready to go into the kiln. Any holes are stuffed with a small strip of 1/8 inch fiber paper. It is important to push it completely into the hole or there will be needles projecting from the top of the hole where the fiber paper didn’t allow the glass to melt downward. Fiber paper acts as a barrier. This small amount of fiber paper will not disintegrate, smell, or burn. It is easily pushed out of the hole when the piece is finished.  

Glue is an area that is useful to discuss in more depth. Glue is used to hold pieces of glass together so that they can go into the kiln in a “put-together” mode. All of the glues specifically for use with glass to accomplish this purpose (among others such as holding frit powder or powdered enamel) take a long time to dry and don’t really hold well if a piece of glass is at an angle, for example. Many people use Elmer’s glue cut by ½ water. But one is cautioned only to use a small amount since this glue must burn off so as not to mar the surface of the piece or inhibit translucency. Having studied glues for another project I was doing, I use instead a PVA glue for archival bookbinding which is much purer. It is acid free and has a neutral PH. It is just called PVA. This glue is made by “Books By Hand” in Albuquerque , NM . There are other pure PVA glues on the market as well. I have not had any trouble with this glue and do not cut it. Nor am I afraid to use it when necessary even if some does creep out under a stringer, for example.

Earlier in this document, I discussed devitrification. While I have had very few problems with it using the methods outlined above, caution does need to be taken from time to time. There are a few devitrification sprays on the market. Some contain lead. However, Fuse Master’s Super Spray is 99.9% lead free. It can be ordered through any fused glass distributor. There are also other solutions that can be used which I will discuss in separate mini documents. If you use an airbrush to apply it, it is suggested that you use respirator. I apply it with a brush but have found that the odor bothers me so I use my respirator when applying it.

The choice of a kiln is probably the most expensive and meaningful purchase one will make. I had very little area for reference when I decided to buy a kiln. I was not aware of the warmglass website nor did I know of any dealer’s in the area. I relied exclusively on what I read about the various kilns on the internet and what I knew of a ceramic kiln since I have one. One might ask why I didn’t use it since glass artists do use ceramic kilns. Glass kilns come in many forms. They have heating elements in the top and usually in the sides. I wanted one that would give the most even heat that was affordable, for me it meant under $1,000 including shipping which can run a few hundred dollars depending on location and how it has to be shipped.) Medium kilns and larger have to be shipped by freight, not UPS, FedEx, etc.

Glass kilns can be top or front loading. Both have their purposes. I am not going into a complete discussion of kilns since I have not used many different ones. I will discuss the type I chose and give the reasons why.

 

I chose a top loading kiln with both top and side elements. Even though I had a ceramic kiln at home – it does not have top elements - I wanted to have a glass kiln that had top elements. I, also, wanted one with a controller. With a controller I can program in all my times. I can determine ramp time – the time it will take for the temperature to increase or decrease from one given temperature to another and the hold time – the time during which a given temperature will be held. Once a schedule is determined, the controller can be clicked on and basically left on its own. For the type of work I am writing about in this manual, jewelry and flat work, the follwoing holds true, at least for me.

For the first 1,000 degrees, I prop the lid of the kiln open about one inch so that gasses can escape. Once the maximum temperature is reached and I want to decrease the temperature, I do NOT open the kiln and crash vent it. I have found that my pieces cool quickly enough to escape devitrification, for the most part, and I do not want to hurt by shocking the fragile fire brick of the kiln. Some people do crash vent; I don’t. I, also, have not found it necessary to look into the kiln at its peak temperature to determine how long a hold is necessary. Some of the logic behind this decision is as follows: I have a number of pieces in the kiln. All vary slightly. I have to have a happy medium. Otherwise I could actually fire some at, for example, 1480 @ 5 minutes, 1480 @ 8 minutes, and 1480 @ 10 minutes. I would see minor differences. What I do is try to gather similar size, mainly thickness size, pieces together and decide on a temperature/time combination. I have never, except when the temperature of the kiln was off, been unhappy with this method. I even follow the same methodology with large plaques that are alone in the kiln. If they are constructed in a similar fashion, I can anticipate the results correctly. With an accurate kiln and controller, I have not had any problems.

The following picture is a picture of the controller on my kiln.

 

It does have the ability to add and subtract time from various parts of the schedule. Each kiln manufacturer uses slightly different controllers. Normally they are described in detail on their websites.

The following picture shows the inside of a kiln. The red circled protrusion is the controller’s thermocouple which measures the ambient air temperature. Different thermocouples measure air temperature differently. Their thickness, whether they are encased in a sheaf, etc. determine the readings. This is one of the reasons why each kiln owner has to experiment with their particular kiln to obtain schedules that work for them. It, also, is why different thermocouples will read temperatures differently. You might remember, that when I first used the kiln, I checked the accuracy of the kiln’s thermocouple with my husband’s fluke meter. While it read at times very differently while temperatures were ramping up and down, when a temperature was held, the differences were constant and very nearly the same.

 

If you look at the above shelf closely, it will appear mottled. That is the old kiln wash. I no longer use kiln wash. I have switched to Bullseye’s ThinFire paper and I love it. I cut out a square piece and put it down on the shelf. I put reusable pieces of glass on each corner to hold them down and then place my pieces on the paper. The paper is fine enough for the back of the pieces to come out smooth.

The following picture shows a cut sheet of ThinFire paper held down with pieces of glass.

One must be careful with both kiln wash and ThinFire paper to not breath the dust. With kiln wash this will occur when mixing the wash and when cleaning it off the shelf. With ThinFire paper this occurs after firing when removing the pieces and when removing the paper which has disintegrated. I wear a respirator for both these tasks. And our vacuum cleaner has a Hepa filter and we clean it often wearing masks when necessary.

When choosing a mask, make sure the cartridge is the correct kind. I read that it should be a P100. The cartridges on my respirator are NIOSH OV/P100 and are purple. Also, especially for women, one size does not fit all. For the same amount of money, we ordered a small for me. If the nose piece is loose, it looses its seal and efficacy.

 

I hope some of these hints have been helpful. I hope to do more in the future. Check the website often for both new articles and new art work.