Perfect Timing

Perfect Timing

           Glassblowing is hard.  This is not a complaint—it is one of the things that I love about the craft. It demands complete attention, adept hand-eye coordination, and perfect timing. Each of the hot shops that I have worked in has been unique and required me to learn a new set of parameters to be able to control the glass successfully.  From a rustic barn with minimal lighting in the dark of a New England winter, to a shop with vaulted ceilings and walls of windows, to an industrial building with florescent lighting, to my mobile shop set up outdoors in full Southern California sun—I have had to learn to read different cues to determine the heat and viscosity of the glass. A few seconds can be the difference between holding its shape and cracking from cooling too far, or between successfully winding on a new gather of clear glass and being so hot that colored glass already on the blowpipe turns entirely liquid and runs off into the pot contaminating the rest of the day’s glass.  Every moment out of the fire, and each touch of a tool chills the glass—to varying effects depending on the thickness, shape, and color of the glass.

           The one of the brilliant things about my mini dragon furnace is that I only burn fuel on the days that I am actually working.  Unlike traditional shops with furnaces that run 24/7 and idle full of molten glass, I light up and shut down each working day. The downside to this, is that every working day starts around 4:30am.  Mornings start by hooking up the trailer, driving to my work site, and unloading/setting up equipment in the dark.  My record time from pulling into the lot to lighting the furnace was 17 minutes—though it takes substantially longer than that to get all of the equipment set up and running.  Most days I have everything situated by about 7:00am.  I spend the two next hours periodically feeding the dragon scoops of glass while planning the day’s production schedule, setting up color trays, and cleaning my tools.

         I begin blowing glass around 9am, usually starting with a project I expect to take a while.  The glass is just barely hot enough to work with at this point, which makes it better suited for thicker or sculptural pieces than delicately blown cups or ornaments.  The thicker the glass, the longer it needs to be in the annealer anyway, so making this sort of item early in my day is ideal.  As the glass heats up, it gets increasingly viscous, allowing me to make thinner pieces more quickly and with fewer trips back to the furnace to reheat the glass. 

When I have a piece of glass on the blowpipe, every move that I make is calculated; each touch of a tool provides information about the current heat/hardness of the glass as well as determining the ultimate shape.  Whether reheating in the furnace, moving from furnace to bench, or working the glass with my tools, I must always keep the blowpipe turning.  The speed of the turn is determined by how soft the glass is; the hotter the glass, the more quickly I have to turn in order to keep it on center–but too fast and centrifugal force changes the shape of the glass, pulling it wider and shorter.  Learning to read the glass, and predict the length of reheats I need between trips to the bench, is something has gotten easier with experience, but which is particular to each shop.  At first, reading the temperature of hot glass in full sun is a bit like trying to determine whether a single lit bulb (in full sun) is 60W or 90W with no point of comparison.  With practice, focus, and perfect timing through repetition I have learned the tells of my glass and my dragon.  I know the hot spots in the furnace, where I can reheat a piece to heat the front while allowing the end closer to the pipe to chill (relative term!), how long I have to wait to take another gather without risking the collapse of the colored core I start with…And I am learning how to play with the variables to different ends, always looking for the best combination of habits to create consistent work.

After I am happy with the shape of a piece, I use a series of quick reheats to attempt to equalize the temperature throughout the glass–allowing thicker parts to warm in the furnace, while keeping the thinner glass from getting too soft by swinging it through the air outside between heats.  It is important that the glass all be as close to a uniform temperature as possible to minimize the thermal stress it will experience as it cools in the annealer.  My shop uses a CAT-60 tube, which is essentially a manual conveyor belt running through a chimney off the side of the dragon, with a fan and a thermostat that aim to keep the temperature zones consistent.  I place the glass into the pipe through a porthole, and it rests at around 1000* until I pull the conveyor and prepare to load the next piece.  Each time I move the conveyor, the glass moves further from the heat source, until after 10 cycles it has reached the opening at the far end, at about 200-250*.  By the time I shut down for the day around 2:30pm, I have typically unloaded the earliest pieces from the morning.  When I load the final pieces of the day, I try to make sure that they are especially uniform and thin, allowing them to cool quickly with the lowest risk of cracking. At the end of the day, ideally I have used all of the glass I melted in the morning–otherwise I have to pull it out of the furnace in a series of gathers and determine whether it is clean enough to remelt or whether it is contaminated by color that got into the pot one way or another.  When the pot is empty, I close the door to keep the heat in, and turn off the propane.  The residual heat in the furnace will continue to be pulled through the CAT-60 until the last piece comes out around 4:00pm. The day isn’t over until the equipment is cool enough to break down and everything is packed back into the trailer.

            On the days that I am not on site with my Dragon, I work on things like cold work (grinding and polishing), order fulfillment, packing and shipping, and working on graphic components for etching commissions.  In total, I spend 50-60 hours per week doing all of the various tasks that come with running a glass blowing business. Like any craft, the time that goes into a single tumbler or goblet is more than the moments between the first gather and a piece being deposited in the CAT-60; it is the years of practice, the hours of set up and tear down, the designing and testing. 

No Comments

Post A Comment