In my late 20’s and 30’s I pursued a glassblowing career, creating, marketing, selling and shipping hand made glass vases and bowls to shops and galleries across the country.
But there was a lot that I never learned, even skills and techniques that I probably should have picked up in college and definitely when I ran my own studio. One of those skills that I never learned was how to make a glass optic cup.
Admittedly, I am not yet great at this new skill, but after watching a few videos and piecing together the best advice I could find, without attending a hands on workshop (which will happen in just a few weeks!) I have put together my 10 Steps To Creating An Optic Cup.
In my version, my personalized version, of making an optic mold cup, I have made a few variations that work for me, due to a few inherent limitations I have as a glass blower.
First, I have a difficult time turning pipes quickly enough to gather the proper amount of glass to create a decently sized cup. So I gather twice, small gathers, to end up with the correct amount of glass on my pipe.
Second, I don’t have my own set of pipes, having sold all of my glassblowing tools when I put glassblowing to the side to pursue being a stay at home dad while my children were school aged. So I use the pipes that are available at the studios that I rent, and they are not always properly sized for cups, but sometimes too large for work this small.
So, without further ado… here are my 10 steps to make a glass optic cup, though it often seems to take more than 10 steps for me, I still need to practice!
1 – Gather glass on the pipe – In this example, I get a very small gather on my pipe, to which I add colored frit, and heat in before starting a small bubble. Once that cools down a little, I gather once more on top of the colored bubble and shape.
2 – The second step is to get a full heat on the glass and let it lengthen a bit before inserting into the optic mold and giving a full blow to really set the ridges from the mold. Remove from the mold and then get a full heat.
3 – Use the tweezers and pull out a small bit of glass. Switch to the combos and, while blowing gently, squeeze down on the pulled glass at the end and turn the pipe, which will result in a tight twist of the ridges created from the optic mold. If and when the glass bubble get to large and round, pull the knob at the end of the piece and stretch the cup out into a long skinny shape.
4 – Get a full heat, and then use the blades of your jacks to create a jack line at the neck of the piece and also cool the sides of the cup as you blow, which should extend the bubble to the bottom of the glass, setting it up with straight sides. I have lots of trouble on this step, usually taking several heats before proceeding.
5 – Full heat, and still using the blades of your jacks, continue to shape the sides of the cup. Using the residual heat still in the cup, flatten the bottom of the cup using the jacks or a wood paddle.
6 – Get a quick heat, or a flash, and then punty up your piece. Since I work alone, I have to hang up my pipe and gather my own punty, attach it to the bottom of the cup and break the cup off from the pipe at the jack line.
7 – Get a small heat at the glory hole and center up your cup if needed. Then get a more complete heat on the top third or so of the cup and open the mouth of the piece to about an inch using the jacks.
8 – After a fresh heat, use the puffer or sophietta to blow out the shoulders of the cup to line up with the sides as set with the jacks in earlier steps. Another heat, open the mouth a bit wider and use the sophietta once more to blow out the cup and shape the shoulders.
9 – One more heat and then use the jacks, both inside and outside of the cup, to open the mouth of the piece until lined up nicely with the hopefully straight sides of your optic cup.
10 – Let the heat even out in the cup by flashing the finished piece a few times. If looking to fire polish the punty mark, knock the piece off on a wooden paddle and use a small propane torch to fire polish before placing into the annealer. Or if you don’t care about the punty mark, knock straight off into the oven.
And there you have it, easier typed than done, but pretty straight forward. This is where I am early in my optic cup career, and will make a point of updating this website as I progress.