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Unit 12: Glass Working

Microcredential ID: U12-GLASS-001 Title: Glass Working Craftsperson Version: 1.0 Duration: 12–15 hours (4 modules × 3–3.75 hours each) Prerequisite: Heat safety orientation (OSHA 10-hour equivalent) Certification Level: Advanced (technique mastery + safety-critical operations)

Unit Overview

Glass working encompasses both cold and hot glass techniques, from precision cutting and grinding to kiln firing and lamp work. This unit develops comprehensive competency in understanding glass material science, executing cold techniques (cutting, breaking, grinding, assembly), operating glass-heating equipment (kilns, torches), and performing finishing work (engraving, etching, surface treatment).

Learners will master fundamental glass properties, execute classic techniques with precision and safety, and integrate techniques for complex, multi-method projects.

Industry Context: Glass working is central to fine art practice, architectural glazing, scientific instrumentation, heritage restoration, and hobbyist/maker communities. The glass art market generates $2.1B annually in North America alone, with strong demand for skilled craftspeople in architectural, beverage, and decorative glass sectors.

Alignment to Standards

OSHA Standards:

  • 29 CFR 1910.252 — Welding, Cutting, and Hot Work (lamp work torch operations)
  • 29 CFR 1910.97 — Non-Ionizing Radiation (infrared hazard from heating/furnaces)
  • 29 CFR 1910.95 — Occupational Noise Exposure (glass grinding and kiln fans)
  • 29 CFR 1910.1200 — Hazard Communication (glass dust, kiln shelf chemicals, enamels)

ANSI Standards:

  • NFPA 30 — Flammable and Combustible Liquids Code (propane and natural gas safety)

Material Science Standards:

  • Coefficient of Thermal Expansion (CTE): Glass types rated by CTE compatibility (e.g., Borosilicate 3.3 × 10⁻⁶/K)
  • Glass Type Classifications: Soda-lime, borosilicate, lead glass, fused silica (each with distinct working properties)

Learning Outcomes

By the end of this unit, learners will:

Knowledge Outcomes:

  • Explain the chemistry and atomic structure of glass (amorphous silica, modifiers, network formers)
  • Describe thermal expansion, annealing, and thermal shock mechanisms
  • Identify glass types (soda-lime, borosilicate, lead, fused silica) and their properties/applications
  • Understand the hazards of silica dust, infrared radiation, and thermal burns
  • Articulate cold glass techniques (scoring, breaking, grinding) and their physics
  • Describe kiln firing cycles, fusing schedules, and annealing curves
  • Explain lamp work basics (melting, shaping, cooling)
  • Understand surface finishing methods (engraving, sandblasting, laser etching)

Skill Outcomes:

  • Perform precision glass cutting (scoring, breaking, edge finishing)
  • Operate grinding equipment safely and achieve smooth edges
  • Create complex cold glass assemblies (mosaic, panel construction)
  • Operate and program glass kilns for fusing and slumping
  • Execute basic lamp work (torch handling, heating, shaping, cooling)
  • Perform glass engraving and etching with multiple techniques
  • Integrate cold and hot techniques in a single project

Competency Outcomes:

  • Independent Operation: Perform cold glass work safely without supervision
  • Advanced Kiln Work: Program and execute firing cycles with precision
  • Torch Work: Execute lamp work with safe technique and quality results
  • Safety Management: Recognize and manage thermal, dust, and radiation hazards
  • Artistic Expression: Create finished glass pieces meeting professional aesthetic standards

Unit Structure

Module Title Duration Focus
M1 Glass Science & Safety 3 hrs Material composition, thermal properties, hazard recognition, PPE
M2 Cold Glass Techniques 3.5 hrs Scoring, breaking, grinding, edge finishing, pattern cutting, mosaic assembly
M3 Hot Glass Techniques 3.75 hrs Kiln operation, fusing schedules, slumping, lamp work basics, annealing
M4 Glass Engraving & Finishing 2.5 hrs Rotary engraving, sandblast etching, laser crossover, surface treatments

Assessment Strategy

Formative Assessment:

  • Module knowledge checks
  • Hands-on technique demonstrations with instructor feedback
  • Peer review of finished work against rubrics

Summative Assessment:

  • Unit Quiz: 50+ questions covering all modules (80% pass threshold)
  • Practical Capstone Project:
  • Design and execute a multi-technique glass piece (must include cold AND hot techniques)
  • Examples: Fused glass pendant with hand-engraved detail; mosaic tile panel with ground edges; slumped bowl with sandblasted design
  • Meet professional aesthetic and durability standards
  • Complete written documentation of material selection, technique choices, and safety measures
  • Equipment Competency Checklist: Safe, independent operation of cutting, grinding, kiln, and torch
  • Safety Certification: Signed hazard acknowledgment and thermal safety protocols

Assessment Rubrics:

Cold Glass Technique Quality (0–4 scale): - 4 = Professional: Precise cuts, smooth edges, clean breaks, perfect fit (if assembled) - 3 = Good: Mostly precise with minor imperfections - 2 = Acceptable: Functional but with visible flaws - 1 = Poor: Multiple technique errors, edges not finished - 0 = Unacceptable: Unsafe or unusable

Hot Glass/Kiln Work Quality (0–4 scale): - 4 = Excellent: Clean fuse lines, proper annealing, no cracks or devitrification - 3 = Good: Well-fused with minor annealing marks - 2 = Acceptable: Functional but with visible defects - 1 = Poor: Cracks, improper annealing, surface defects - 0 = Failed: Broken, shattered, or unusable

Safety Protocol Adherence (0–4 scale): - 4 = Exemplary: All protocols followed consistently; proactive hazard awareness - 3 = Competent: Follows all protocols with occasional minor lapses - 2 = Acceptable: Understands protocols but occasional violations - 1 = Needs improvement: Multiple safety oversights - 0 = Unsafe: Systemic non-compliance or hazard creation

Instructional Resources

Digital Resources:

  • Slide decks (5–6 per module) with embedded instructor notes and safety warnings
  • Videos: "Glass Science Basics" (5 min), "Safe Kiln Operation" (7 min), "Torch Work Fundamentals" (8 min)
  • Interactive kiln firing schedule calculator (spreadsheet or online tool)
  • Thermal expansion (CTE) compatibility chart
  • Glass type properties table (soda-lime vs. borosilicate vs. lead vs. fused silica)
  • Troubleshooting guides: Cracks, devitrification, poor fusing, annealing failure

Physical Resources:

  • Glass cutting tools (glass cutter, cutting oils, breaking pliers, straightedge)
  • Grinding equipment (wet grinder with diamond wheels; 7–9 inches diameter)
  • Glass samples for practice (variety of types and thicknesses)
  • Kiln (programmable electric kiln, 8–15 cubic feet; brands: Paragon, Skutt, Fused Glass Supply)
  • Kiln furniture (kiln shelf, stilts, fiber blanket, separator wash)
  • Lamp work torch (tabletop burner or handheld, propane/natural gas)
  • Lamp work tools (punties, shaping tools, marver, molds)
  • Annealing oven (optional but recommended for proper cooling cycles)
  • Engraving tools (rotary engraver or flex-shaft; diamond or carbide burrs)
  • Sandblasting cabinet (from Unit 10) for etching work
  • Eye protection: UV/IR goggles for kiln viewing; safety glasses for cold work
  • Thermal gloves and apron for hot work

Reference Materials:

  • "Glass Science for Artists" (handout with chemistry and properties)
  • Kiln firing curve examples (fusing, annealing, cooling rates)
  • Thermal shock prevention guide
  • Lead glass hazard information and safe handling protocols
  • Annealing schedule reference (depends on glass thickness and type)
  • Engraving pattern library or design templates

Safety Emphasis

Glass working involves multiple thermal and chemical hazards. This unit prioritizes safety through:

  1. Hazard Recognition: Early identification of risks specific to each technique
  2. Engineering Controls: Equipment design features that reduce hazard exposure
  3. Administrative Controls: Procedures, timing, and facility design that minimize risk
  4. PPE & Protocols: Proper protective equipment and mandatory safety procedures

Every module includes dedicated safety sections and emergency procedures.

Accessibility Considerations

Inclusive Design:

  • High-contrast diagrams of glass properties, kiln curves, thermal zones
  • Audio descriptions of thermal color changes in glass (critical for kiln work)
  • Written step-by-step procedures supplementing visual demonstrations
  • Extended time for fine motor tasks (cutting, engraving) if needed

Neurodivergent Accommodations:

  • ADHD: Hands-on work provides engagement; shorter lecture segments with movement breaks
  • Dyslexia: Color-coded safety zones (hot = red, cold = blue), visual procedure cards
  • Autism: Predictable kiln schedules, explicit thermal expectations, quiet workspace for sensory sensitivity
  • Motor differences: Adaptive tools for grip (larger handles), height-adjustable work stations

Certification Pathway

To earn the "Glass Working Craftsperson" micro-credential:

  • [x] Complete all 4 modules
  • [x] Pass unit quiz (80% minimum)
  • [x] Complete all hands-on activities with demonstration of technique
  • [x] Pass practical capstone (multi-technique project, 85% quality standard)
  • [x] Demonstrate safe, independent operation of all equipment (cutting, grinding, kiln, torch)
  • [x] Pass thermal hazard recognition test (identify 8/10 thermal risks in scenario photos)
  • [x] Sign thermal safety protocols and hazard acknowledgment form

Advanced Pathways

Learners who complete this unit may continue to: - Unit 09 (Vinyl/Heat Transfer): For heat-based finishing integration - Unit 10 (Sandblasting): To combine glass etching and sandblasting finishes - Independent Projects: Custom glass art, architectural installations, scientific instruments

How to Use This Unit

For Instructors:

  1. Test all equipment (kiln, grinder, torch) before each session
  2. Ensure proper ventilation in kiln and torch work areas
  3. Have thermal gloves, safety glasses, and first-aid supplies readily available
  4. Establish clear thermal safety zones and do-not-cross boundaries
  5. Provide live demonstrations of each technique before learner practice
  6. Never leave kiln or torch operation unattended with learners

For Learners:

  1. Understand that glass is both beautiful and hazardous
  2. Respect thermal zones; never reach into or near hot equipment
  3. Wear all required PPE consistently
  4. Ask for help if you are uncomfortable with any procedure
  5. Treat glass scraps and dust carefully (can cause cuts and respiratory irritation)
  6. Complete extra practice with simple projects before attempting complex designs

Prerequisites & Sequencing

Hard Prerequisites: - Heat safety orientation (OSHA 10-hour equivalent) - Physical ability to wear thermal protection and work at height

Soft Prerequisites: - Some artistic or craft background helpful (but not required) - Completion of Unit 10 (Sandblasting) recommended for etching integration

Recommended Sequencing: - Complete Unit 12 last in the 4-unit sequence - Pair with Units 09 and 10 for comprehensive finishing capability

Version History

Version Date Changes
1.0 March 2026 Initial release: 4 modules, 16+ lessons, full assessment suite, thermal safety protocols

Ready to start? Begin with Module 1: Glass Science & Safety →

M1: Glass Science & Safety