How to Make Glass Cups

Making glass cups allows you to express your creative style in an enjoyable and useful way. Cups have no rules and therefore can be any shape, design or form that you can dream up. You can create glass cups using various methods, although one of the most common uses the lampwork process. After you learn to create a basic cylinder body, you can go on to create advanced compositions.

Things You'll Need

• Ventilation system 
 Didymium safety glasses Clear or colored tubing: 40mm heavy wall Graphite plate Torch kit Propane or MAPP gas 
 Pressurized oxygen (not required for Hot Head torches) 
 Clear blow tube: 15mm to 19mm heavy wall
 Clear glass rod: 8mm Necking tool
 Diamond sheers Graphite paddle
 Graphite reamer Inside-out claw grabber
 Kiln

Instructions

1. Work in a well ventilated area, wearing safety glasses with didymium lenses.

2. Constrict one of the open ends of your 40mm tube by rotating and heating the glass in the torch flame, then angling the molten end down on a graphite plate. Make the diameter size close to that of the blow tube so you can attach the two easily.

3. Rotate and heat the ends of both the narrowed tube and blow tube until they're molten. Attach the two glass pieces while maintaining a consistent rotation so that they're securely welded. Make sure not to close the opening between the 40mm tube and the blow tube. The blow tube serves as the instrument that you blow through and as one of the handles that holds the tubing.

4. Flame cut approximately 3 inches of the 40mm tubing to separate this section from the remainder of the tube. Hold the blow tube handle in one hand and the 40mm tube in the other. Continuously rotate and spot heat the area that you're detaching. As the glass becomes hotter, it will compress and eventually separate.

5. Rotate and heat the ends of your 8mm rod and the closed end of your tubing. As the ends become molten, touch the two pieces in the flame while rotating. Move out of the flame and continue to rotate so that your rod is as centered as possible. In alliance with the blow tube, you will use this 8mm rod, called a "punty," to hold your bubble steady as you blow it out.

6. Rotate and heat the 40mm tube from one side to the other until it begins to glow. Gently put pressure on the blow tube and punty so that the glass begins to gather and form a ball. When the glass has an even heat base all the way around the tube, move the blow tube/handle to your mouth and give a few short puffs while always rotating. You're aiming for a nice even bubble, but this takes practice and is best accomplished in a few steps rather than in just one try. Blowing in short progressions helps to keep the bubble on center and allows you to maintain control over your work.

7. Rotate and heat the upper two-thirds of the bubble further back in the flame. Angle the bubble up and then down while rotating and heating. Obtain a cylinder shape by elongating the bubble using gravity as a tool. Once the bubble is the desired length, pull the glass out of the flame and give it a soft puff to keep an even wall thickness.

8. Rotate and heat the area near the blow tube and bring it down gently on the necking tool. Rotate the tube against the tool so that an indentation forms and narrows the opening. This defines the top of your cup and makes it easier to separate from your blow tube.

9. Lightly heat and rotate this indentation. Pull the glass out of the flame and use the diamond shears to give the indentation a few uneven crimps. Tap the blow tube with the diamond shears so that the blow tube falls away and leaves a small, even hole. If it doesn't detach, repeat the heat and crimp process.

10. Heat the small opening of the glass and use your graphite paddle to even out the top. When it's flat, heat the opening and insert the graphite reamer to flare open the cup. Enter the opening at an upward angle so that the glass rests on it as it's being circled in the flame. Do this in short steps so as to not lose control of the flare and to achieve the opening that you want.

11. Attach the inside-out claw grabber to the inside of the cup. Then heat the bottom of the cup so that the glass thickens. Flame cut the punty off to remove it from the bottom. Continue to heat the bottom. Remove the glass from the flame and gently rotate the cup against the graphite paddle. Test the cup to ensure that it stands straight. If it wobbles, reheat and paddle as many times as is necessary.

12. Place your cup in your kiln to anneal the glass.

Tips & Warnings

• If you get wrinkles before blowing out your cup in Step 5, ease up on the pressure because this indicates that the glass is being pushed too hard. Make sure that your punty is on center and that you continuously rotate your work to keep everything on axis.

• Do not blow your bubble in the flame because you will thin out the wall thickness too much and lose control of the shaping. Never begin lampworking until you understand all the health and safety considerations and set up a proper ventilation system.

References

• Flameworked Goblets: A Lesson with Eric Goldschmidt; Goldschmidt; 2007

Resources

• Corning Museum of Glass
• Lampwork Etc.