This article details how I blew off-hand glass for the first 4.5 years, with energy efficiency being paramount. The shop setup is for a single day of glassblowing, where equipment is powered up & shut down the same day with only the annealer running and finishing things up overnight. There is no 24/7 furnace full of glass. A day of blowing glass uses approximately the amount of electricity of running our home’s AC on a Summer day and the propane gas of our heater for a couple of cool Winter days. This setup certainly has its production limitations of scale and quantity of work, but within those limitations is an infinite potential of hot glass creations. It also allows one to melt and blow small batches of various glasses, including recycled bottle glass.
 This shop setup is built around a single glory hole working triple duty as the glory, the melting furnace, and the pipe warmer. It’s powered via a low pressure propane burner (Giberson head) & natural air blower (Maxon M100) and is pretty much the stock built (by Aaron Gross of Austin Art Glass) 12″ glory found in Dudley Giberson’s “A Glassblower’s Companion” although this one is about 11″ with doors open.  My annealer is a Skutt GM1414 glass kiln (8328 watts) and I built a bench, yoke, etc from scrap metal. A piece of angle iron welded across the right glory door holds the pipes & punties just inside the opening for preheating. The pipes usually need a short flash to get red.  I make crucibles of Raku clay, which is groggy and takes well to thermal shock. The crucibles aren’t large, having only about a three to four pound glass capacity. This works for my production needs of ornaments, small vessels, and wall art. I originally formed the crucibles using literally anything roundish as a mold but now only throw the clay for even wall thickness.   I fire the formed, dried crucible once to cone 04. Then on blow days, I bring up the crucible in the annealer to 1280°F, lighting the glory about 30 min prior to reaching the 1280°. I move it to the glory with preheated tongs and place it on chunks of kiln brick near the back of the glory. I let the glory & crucible heat for a bit before charging. The glass cullet is preheated to around 950°F so it will not shock & explode when I charge the crucible (many smaller charges till it’s full). I’ve also tried precharging the cold crucible so the glass melts during the glory’s heating but this seems to take just as long or longer to get the glass to a working temp.  The glass is very bubbly, so I twist it with a punty between charges which removes the larger bubbles. I gather a punty, heat it in the flame until uncontrollable, and then drizzle it back around the inside edges of the crucible. All my glass is seeded with tiny bubbles – which may be a large issue for some artists, but it has been a proud hallmark of energy efficient glassmaking for me. It takes about 3-5 hours from lighting up before we start gathering for blowing. I keep a metal bowl of glass charge heated at 950°F in a small 120v kiln. When the crucible gets low I can charge & melt another crucible of gatherable glass in about 20-30 minutes. When the blow day is done (and crucible emptied), I put a blanket of fiber frax in the doorway of the glory so the heat will slowly dissipate and the crucible survives (usually). Some crucibles will crack after a few uses but I’ve had others last well over a year.  With this setup, I only blow as often as every other day as the glory & crucible are still too hot the day after. With the annealer, a 120v Cress kiln for preheating the charge (and color pickups), lights, fans, blower, etc I’m seeing an average of only 46 kWh a blow day in electricity (which is subsidized wind power via our power co.’s Green Works program). My propane usage for this single glory setup is under 10 gallons per blow day. After blowing hundreds of wall pieces and thousands of ornaments with this setup, I recently added a dedicated “furnace” to the studio — a Paragon Darby Dipper crucible kiln (2280 watts). It uses a 6″x7″ 8 lb capacity Engineered Ceramics crucible and runs on a 120v 20amp circuit. I run it for less than a week at a time and can blow consecutive days with it – charging it up after each blow day and melting overnight for bubble-free glass the next day. My energy usage is showing this kiln is adding only around 30-40 kWh per day. Using this little crucible kiln in place of melting in the glory hole has reduced the propane usage per blow by about 1/2. I plan to craft a separate post about my experience with the Darby Dipper. I hope this info helps! I will keep it updated & edited as needed and try to answer questions. A special thanks to my amazing wife and assistant Carrie, who has been an incredible partner in following this passionate path of hot glass! All the best, COMMENTS or QUESTIONS?
 Cold annealing kiln after a long day of blowing ornaments  Cold annealer with ornaments, wall art, & vase |
