Fused Glass Design Elements - Glass Combing

Fused glass bowl with combed design

Glass combing, or raking, is a fused glass technique where the glass is heated to a temperature high enough to allow the glass to be manipulated in the kiln. The glass is typically brought to between 1600 and 1700 degrees fahrenheit and then a stainless steel tool (or rake) is used to swirl the glass.

I have taken several classes where glass combing has been a small portion of the class, but this year at the Glass Craft and Bead Expo I had the opportunity to take a day-long class dedicated to combing with Janine Stillman. Janine is a great teacher, and the class was a catalyst to get me thinking about creating intentional designs with combed pieces. I've spent some time experimenting with combing the last several weeks, taking pictures along the way, so I thought I would share some of the results in a blog post.

Typically glass combings are done by cutting strips of glass and laying these strips on edge to be combed. I have done combings this way, and I've also done some pieces where at least a portion of the glass has been larger pieces of glass, stacked instead of placed on edge, with the idea that these larger pieces were background glass and would be uncombed. My experiences have taught me that strips or smaller pieces of glass are better for combing. I have experienced pinhole-sized bubbles with the combings I've done with larger pieces of glass. The bubbles did not significantly detract from the piece, but I would have preferred not to have them at all. Using strips or smaller pieces of glass ensures air has a chance to escape, thus avoiding bubbles.

Cress GK2 drop-bottom kiln

The kiln I use for combing is a Cress GK2 drop-bottom kiln. As the name implies, the bottom of the kiln drops down by using a lever. This type of kiln is ideal for combing because the heat is contained within the kiln and your working area is well away from heating elements. The kilns are also designed to heat quickly and easily maintain temperatures hot enough for high temperature combings and pot melts.

Warning: Follow safety precautions when combing glass! Always turn off the kiln. Wear IR eye protection (a face shield is recommended). Wear non-flammable clothing (cotton -- no synthetics, long sleeves, long pants, closed toe shoes). Tie back long hair. Wear heavy-duty, non-flammable gloves. Comb with a partner. This is not an all-inclusive list of the precautions that should be observed when working with extremely hot glass in an extremely hot kiln! Always follow your kiln manufacturer's recommendations. 

Glass strips dammed
and ready for firing

Here is the layup for a couple of pieces that later would be used as design elements in other pieces. I was trying to optimize kiln space and firing time, so I set up three combings, separated by dams and fiber paper. The dammed pieces were laid out in a stainless steel fusing square.

Combed pieces ready to anneal

To the left are the pieces after combing, hot in the kiln and ready for annealing. The piece on the left was combed from each outer edge inward, stopping in the middle. For the middle piece, the white (actually Spectrum's vanilla cream) was swirled into the other colors of medium amber, sky blue, and dark amber. With the piece on the right, I combed down through the squares at the top to create the look of flowers. Tip: Wear a headlamp or ask your combing partner to shine a flashlight on the glass to better see the different strips of glass and the design while combing.

Here are the combed pieces above incorporated into completed pieces, after several more firings in the kiln.

Yellow, apple jade, orange, white

Vanilla cream, apple jade, sea green, clear

Dark amber, medium amber, sky blue,
vanilla cream

Here is another layup I did, using larger pieces of glass.  I first drew up the design on paper, and then cut and assembled the glass in a metal fusing ring. I was using Spectrum's Vanilla Cream glass, and I wanted to include some strips to take advantage of the nice reaction achieved when the pieces are placed on edge. If you look closely at the finished piece, you'll see that the layup resulted in a few pin-hole bubbles. If I were to do this over again, I would create the design piece first and incorporate it into the background glass later to avoid the bubbles.

Glass set up in the metal ring

Laying out the design on paper

Close-up of the combing after firing:

Close-up of combing

Finished bowl

And here is the finished bowl after more firings and coldworking.

Celtic knot design
Combing was completed in Janine's class.
I incorporated it into a finished piece
at home. 

Glass combing opens up a world of design possibilities in fused glass. I hope this short blog post has inspired your creativity and helped you to understand what is possible by manipulating glass in the kiln!

Dana

Resources: 

Safety in the Kiln technical note, Bullseye Glass: https://www.bullseyeglass.com/images/stories/bullseye/PDF/other_technical/kiln_glass_safety.pdf

Janine Stillman, Designs by Ja9 (including information on classes): http://www.designsbyja9shop.com/
Patty Gray, Glass combing instructions: http://www.pattygray.com/demo/instructions.html
Stainless rings and squares for fused glass, Bonny Doon Fused Glass: http://bonnydoonfusedglasstools.com/stainless-steel-forms/
Cress kilns, GK2: http://products.cressmfg.com/item/all-categories/glass-kilns-2/gk2?

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Combings in the kiln ready for the final
firing to slump into molds