In my last article, I discussed some of the most basic techniques involved in working soft glass in a flame. In this article, I will attempt to describe as clearly and simply as I can, a few of the more advanced techniques I have learned, or at least observed. I must say before I begin that I have, at best, limited experience with many of these techniques, so bear in mind that none of this is written in stone. If anyone experienced in working soft glass reads this and sees something they believe is inaccurate or misleading or just plain wrong, I would appreciate it enormously if they would take the time to write Glass Line and clue me and the rest of us in. I also want to thank those of you who have written or called me to talk, ask questions, or just to say encouraging things. The whole point of these articles is to initiate dialogue and it is very gratifying to know it is working.
The first technique I would like to discuss is called "spin - trailing". Spin - trailing is a common surface decorating technique that is also used as a basis for other decorating techniques. Begin with a point that you have already shrunk and rolled in colored powdered glass. Be sure it is hot, symmetrical and on - center. Heat the tip of a rod of glass of a contrasting color until you have a small ball of molten glass. Holding the piece with your left hand (reverse this if you are a south - paw), place the other point on a secure roller or a "notch" so you can spin the point rapidly. Touch the molten ball to one end of your piece and draw back quickly to pull a thin strand of glass. At the same time, spin the piece away from you at a steady, rapid rate. The thin strand will be wound onto the spinning piece. It is important to note here that this move is done out of the flame. Move the heated rod steadily from one end of the piece to the other to distribute the trailing over the entire piece, bringing it back to the flame only to burn off. (see figure 1) The trailing can be applied in a single perfect spiral or in many random criss - crossing lines. Reheat the entire piece to melt in the trailing completely and continue your procedure.
The next technique I will describe is "festooning" and "feathering".( There are those who would point out that these can hardly be considered "advanced" techniques, but I would remind them that "advanced" is a relative term and these techniques should be considered advanced for the majority of us.) Festooning and feathering are effects in the surface decoration of a piece that are achieved by combing trailed - on bands of color into points. In a festooned pattern, the points only go one way. In a feathered pattern the points alternate in either direction. To do these types of decorations, you must first be sure the piece to be decorated has sufficient wall thickness to withstand the combing process. I would consider walls any thinner than 1/8" to be too thin. Shrink your piece down so the wall thickness is 1/8" or more and it is somewhat elongate in shape. Keep the entire piece evenly heated at all times, but not so hot that it is losing its shape. Spin - trail on several bands of colored glass and melt them in. Dial in a tight oxidizing flame and carefully heat a narrow band perpendicular to the trailing across the entire length of the piece until the glass in that band is soft, but be careful not to get it so hot that it starts to collapse. Take your combing tool, usually simply a pointed implement, and quickly drag it down the length of the heated band. You will have to stick it into the glass a little, but not too deep; just enough to start the glass moving. Follow the combing tool with the flame but do not put the flame on the piece until you reach the end of the comb. Then use the flame to burn off the strand left from the combing. The entire process should be accomplished in one smooth, quick move. The trailed pattern will now have a sharp dip in it where all the lines converge at one end of the piece. Repeat the process, spacing the combing evenly around the piece to make a pleasing pattern. If all the combings go toward one end of the piece, the pattern is known as "festooning". If the combings alternate directions, it is known as "feathering". (see figure 2) The combing process leaves fairly deep gouges in the surface of the piece which must be removed by reheating and re-shrinking the piece and then blowing it back out to its final shape.
Another interesting combing technique is one called "drag - combing", or, as I sometimes call it, "cold - combing". In this technique, the surface of the piece is just moderately heated, not enough to soften the surface but enough so that when it is touched with the combing tool, the decoration is moved just a little. The technique differs from regular combing in that, instead of sticking the comb into the piece and pulling a section of melted glass to a point, the comb is just sort of scraped or dragged over the surface without digging into the glass.The comb is dragged over the surface many times in many places, repeatedly reheating the piece just enough to make the pattern move a little bit. The final effect is a waviness sort of like a seismograph readout. This technique is particularly effective if the initial trailing is not melted in all the way and the combing is not done until the piece is nearly complete. This creates an unusually coarse surface that is pleasing because it is so uncommon in lampworked glass.
Speaking of coarse and uncommon surfaces, here is a technique I did not believe was possible until Shane Fero showed it to me. First, you color a point by rolling it in powder, preferably a dark primary color like black or cobalt blue although I have achieved stunning effects with some pastels like pink (kugler #66) and sky - blue (kugler #80). Then you allow the point to cool completely. Once cool, you use a fine bristled artist's paintbrush to apply a coat of gesso. Yes, gesso, the acrylic and kaolin based paint that artists use to prime their canvases! Apply the gesso in even strokes but do not worry about brush marks. The brush marks give this technique its most striking effects. In fact, the effect may be varied enormously simply by changing the direction and /or length of the brush strokes. Allow to dry completely. Now reheat the point in a vigorous pure gas flame for at least 60 seconds. Then, dial in a medium neutral flame and slowly bring the point up to working temperature. Be careful not to breath any of the smoke or fumes coming off the point. Always be sure to work in a well ventilated area ! Once at working temperature, the point may be worked into a final shape using any of the techniques you would normally use. Amazingly, the gesso stands up to the extreme heat, and even more amazingly, bonds to the glass. The final effect is stunning ! A surface with a delicate, lacy pattern of powdery white ridges and reticulations. The brush strokes now reveal themselves as a pattern of irregular lines traversing the shape of the vessel. With skill, the artist can play the shape of the vessel off the delicate surface to create a piece with incredible eye - appeal. And yes, you borosilicate purists, it will work with pyrex too !
A similar, if not so startling technique is to use Hanovia bright gold in the same way. You must be sure to get an even coating of gold when you paint it on and you have to be sure to let it dry completely before reheating. You had better be sure not to breath any of these fumes because they contain toluene ! You can reheat the point in the same way as the gesso but I sometimes will reheat them in my oven set at 810 degrees using the worm hole. You also must be very careful when working it not to overheat any particular area of the piece because the gold is thin and delicate and can be easily heated away completely. I generally stick to simple shapes that do not require extensive heating when using this technique. The result is quite beautiful particularly if the background color is black (kugler #54). The gold reticulates into unexpected patterns and retains a good bit of its shine.
Another excellent surface decorating technique that yields unusual and widely varied results is applying shards. I'm not going to get into that in this article though, having already described making and applying shards in detail in a previous article (Glass Line - Vol 4 #5 - 1991). There is no appreciable difference between working with shards in borosilicate glass and with soft glass except that the soft glass tends to melt in more quickly.
In truth, glass may be applied to the surface of the piece in almost any conceivable form, but sometimes it seems that the simplest, most obvious methods yield the most interesting results. A good example of this is the application of frit. Frit is nothing more than ground up glass and is obviously very easy to make. Ed Hoy sells an excellent frit maker that is nothing more than a heavy duty mortar and pestle. A few chunks of glass, a couple whacks with a hammer and voila...instant frit ! If it is a particular size of grit that you seek you can either use a screen or do like I do and use a sheet of paper. (All you former "heads" out there should know this trick !) Sprinkle the frit onto a sheet of paper and gently shake it while holding it at a slight incline. The larger, heavier chunks will roll off first and the lightest will stay behind effectively graduating the frit size from fine to coarse.
Frit is applied in a number of ways. I usually sprinkle it onto my marver board and roll the heated piece over it. Some people like to arrange the frit into patterns that they then pick up by rolling over them. Others like to sprinkle the frit directly on the heated piece, or even pour some inside the piece and then heat it until it coats the inside of the piece. All these methods yield interesting results in hard glass as well as soft. One word of caution. If you use the same frit grinder for both hard and soft glass, be sure to wipe out the inside thoroughly after each use. Even microscopic specks of hard glass can destroy a piece of soft glass.
One important technique that is elemental to many other complex effects is twisting overlayed decorations. In this method, a simple parallel pattern is made more interesting by heating and twisting the point. Typically, a series of bands of contrasting colored glass is laid down parallel to the axis of the point. Then, the point is shrunk and the bands melted in only, while doing this, the lampworker also makes a conscious effort to turn one point at a slower rate than the other. The result is that the pattern twists as the point shrinks. Invariably, the walls of the point will tend to buckle under the stress of the twisting in which case the lampworker must stop the turning and blow to restore the shape before continuing. By gradually coaxing the piece along like this, very tight twists can be achieved with no unreasonable variations in wall thickness. This technique can make for some nice decorations by itself, but it is when used in conjunction with other more complex techniques that its real value is appreciated.
One such technique, perhaps the most complex technique, is montage. I am really going out on a limb to try to describe this technique because it is extremely difficult to do and I have only limited experience with it. However, I feel that this article just does not deserve its title without describing at least one truly advanced technique. As a basic definition, montage simply means that the final piece is made up of an assemblage of smaller pieces. Usually the lampworker starts with a single bubble and, one by one, adds and melts in additional bubbles of varying colors and decorations until the final bubble is composed of many colors and decorations blending together in fantastic patterns. The number of additions can range from one to literally dozens. Complex montages can take a master lampworker all day to make just one piece ! Fred Birkhill has told me on more than one occasion that doing montage would change me as a lampworker forever.
Let's start with a simple montage, just two additions. Some initial preparation is necessary. You will need a glassblower's swivel attached to a few feet of 1/4" plastic tubing. You will also need a couple of plugs. These can be made of 1" lengths of 1/4" plastic tubing with one end stuffed with a short piece of glass rod to close it. The bubbles to be added must also be prepared first. In this example let's make two small (about 1" in diameter) white bubbles with twisted black overlay (kugler #61 and #90). Open one end of the bubble to a hole that is 1/2" in diameter and flared a little to give it a nice round lip. Flame anneal them thoroughly and place them in your annealing oven (set at 850 f) with the points sticking out of the worm hole. Now prepare the main bubble by shrinking a 3" piece of 25mm tubing and coloring it by rolling it in some cranberry (kugler #232) colored glass powder. Blow it into a 2 1/2" oblate bubble with a diameter of about 1" at its widest point. Open one end and flare it until it is about 1/2" in diameter and has the same nice round lip you gave to your prepared additions. OK, now use one of your plugs to stop the point on your main bubble. Remove one of your prepared additions from the oven and attach the swivel to its point. Now, carefully heat the two 1/2" round holes and make the seal as evenly as possible. Once the seal is made, draw the two bubbles apart a tiny bit and blow into the swivel to smooth any wrinkles in the seal. Then begin heating the entire end where the seal was made. You must shrink and blow the glass until the "neck" where the seal was made disappears and the addition conforms to the shape of the main bubble. (see figure 3) This is tricky and requires a great deal of skill. The wall thickness must be somewhat consistent and the shape reasonably even and on-center. Repeat the procedure for the other addition at the other end. By this time the bubble will be double its original size. Continue to heat, shrink, and blow the bubble while pushing the ends toward each other to cause the bubble to become more and more spherical in shape. When you have the bubble as close to a sphere as you can get it, you are ready for the next step...axis change !
At this point, you should have a spherical bubble, cranberry in the middle with either end white with black spiral stripes culminating in a point. The two original points of the main bubble have been discarded but don't throw them away. You'll need them later. Now burn off whichever point is plugged being careful not to disrupt the pattern of spiral bands. Heat the resulting dimple and blow gently to round off and smooth that end, leaving a "target"-like spiral pattern. Reheat the entire bubble for 30 seconds in a pure gas flame ( you should be doing that from time to time anyway). Then dial in a tight, oxidizing flame and pop a small hole exactly halfway between the ends in the middle of the cranberry band. Use a reaming tool to open the hole to about 1/4" to 1/3". Then, plug the remaining point. Locate one of your discarded points, blow out the end, attach your swivel to it and seal it to the small hole in the bubble, blowing into the swivel to smooth and strengthen the seal. Be sure you attach the point exactly perpendicular to the previous axis and do not leave any holes in the seal ! Now you must burn off the remaining point, only this time the points are at right angles to each other making control much more difficult. As before, take care not to mess up the spiral pattern and heat out the dimple. Now would be a good time to give the piece a 60 second soaking in a pure gas flame just to settle it down. Now, locate another of your discarded points and heat the end to a solid ball. Locate the spot on the bubble directly opposite the existing point and seal the new point there. There you are, a successful axis change ! Now you can heat, shrink, and draw the spherical bubble back down to a more manageable oblate shape and blow it into any thing you want.
I can honestly say, the first time I successfully performed this procedure, I really did feel like a changed man! And this was a simple montage ! Imagine the East German master lampworkers like Kurt Wallstab and Albin Schaedle doing montages with a dozen or more additions ! Fred has pointed out to me that the East Germans use a burner that is quite different from the gas-oxygen burners that most of us use. Their burner has three valves, one for gas, one for oxygen, and one for air. In the video I have of Wallstab demonstrating at Pilchuck, he has the air turned on for better than 80% of the procedure, just keeping the piece hot. The air makes a loud, bushy, high volume flame that Fred considers essential to the montage process. I noted that the flame appeared to be highly reducing in nature and Fred said that it was. The East Germans use only soda-lime glass, which is less prone to reduction than lead glass, for that reason.
One tool that has helped me in my efforts to do montage is a supplementary burner that Fred made for me. (see figure 4) It is simply a gas burner consisting of a cylindrical head, a needle valve, and a venturi. It sits flat on my bench and I just leave it running when I do montage, and many other soft glass procedures as well. I use it to keep pieces hot while I preheat or prepare other components. It has made all my soft glass procedures go more smoothly and I have been losing fewer pieces during their construction. You could build a similar one yourself or I understand Ed Hoy sells something like it. It will definitely help anyone working in soft glass.
Well, that's it for this article. This is also the last article I will be writing on soft glass, at least for a while, having exhausted my current knowledge on the subject. If I learn any new tid- bits worthy of passing on to you, I will do so. If you have anything to add to what I have written, please take the time to write to Glass Line and share your knowledge with all of us. If you have any questions, I will be glad to try to answer them, and if I can't, will try to refer you to someone who can. Keep the flames burning !
Robert A. Mickelsen