Making uranium glass

Scientific concepts & nature phenomena presented

Uranium glass: composition, fluorescence, and radioactivity

• Uranium glass is ordinary glass containing small amounts of uranium compounds, not uranium metal.
• Color change and dopants
  • Pure uranium glass is described as typically yellow.
  • The example cup is green, attributed to iron being added as an impurity/dopant.
• UV fluorescence
  • Uranium compounds in the glass fluoresce under black light/UV, producing a characteristic green glow.
• Radiation at low concentrations
  • The uranium content in the glass is small, so the glass is only mildly radioactive overall.
• Historical/scientific context
  • Uranium-glass production was common in the late 1800s/early 1900s, then disrupted during World War II due to government confiscation for nuclear research, and later restarted with more awareness of radiation health risks.

Radiation types and detection instruments

• Ionizing radiation types mentioned
  • Alpha particles (mainly emitted by uranium), plus beta and gamma.
• Geiger counter limitations
  • The first Geiger counter used cannot detect alpha particles.
  • It can detect beta/gamma, so its readings underestimate the presence of alpha-emitting uranium.
• Units for radiation
  • cpm (counts per minute): instrument counts, not dose.
  • Sieverts (µSv/hr): dose-equivalent, used to compare hazard more meaningfully because it accounts for radiation type.
• Background radiation measurement
  • Baseline environment reading reported: ~15 cpm (low natural background).

Uranium chemistry used for glass doping (method outline)

• Starting material
  • Instead of refining uranium ore, the process begins with depleted uranium (missing the isotope needed for nuclear power/weapons, but still usable for glass coloring).
• Uranium compound: uranyl nitrate
  • Uranyl nitrate is described as forming yellow crystals and fluorescing under UV when pure.
  • It emits “thousands of extremely small particles” invisibly—i.e., it is radioactive but not perceptible without instruments.
• Conversion to sodium diuranate
  • Step 1: Dissolve uranyl nitrate in water, then filter to remove cloudiness/solids.
  • Step 2: React with sodium hydroxide (lye/drain cleaner)
    • Add NaOH slowly to the uranyl nitrate solution.
    • Sodium diuranate precipitates because it is practically insoluble in water (forms “doughnut-looking” solids).
  • Step 3: Determine reaction completion by pH
    • Use pH paper; add hydroxide until around pH ~10.
  • Step 4: Filter and wash the precipitate
    • Use coffee filter + distilled water washes.
  • Step 5: Drying strategy to reduce aerosol/dust
    • Dry under vacuum with drying salt to prevent dust (“death clouds”).
    • Final drying completed only in the closed storage/vacuum chamber to minimize handling and airborne contamination.

Glass chemistry and fabrication (method outline)

• Goal: create borosilicate glass that includes uranium (via sodium diuranate).
• Begin with a low-melting glass former mix (powders)
  • Silica
  • Sodium carbonate (flux)
  • Boric acid (converted during heating to boron trioxide, plus water vapor)
• Powder preparation
  • Blend and then mechanically mill/blend to obtain a fine flour-like powder.
• Melting process
  • Heat to around ~1100°C in a furnace until liquefied.
  • Add mixture in portions; bubbling explained by boric acid decomposition into boron trioxide + water vapor.
• Effect of additives
  • Emphasizes that pure silica melts far higher (~1700°C, and practically requires >~2000°C for workable melts), so additives reduce melting temperature.
• Uranium incorporation
  • Uranium content discussed as typically 0.1% to 3% by weight; the video uses ~0.25 wt%.
  • Uranium powder must be very carefully ground to minimize dust and ensure mixing.
  • Melt uranium-containing mix and pour into molds.
• Fluorescence optimization
  • UV glow is tested at different stages:
    • Initially weak at high temperature / during early cooling
    • Stronger when cooled to room temperature
• Thermal stress and failure mode
  • Glass spontaneously cracks/splits due to uneven cooling and internal stress.

Annealing (stress relief in glass) (method outline)

• Why anneal: reduce internal stress by allowing atomic rearrangement.
• Annealing parameters
  • Hold around ~450°C for several hours (overnight in practice).
• Procedure
  • Melt/pour uranium glass disk(s).
  • Place into annealing furnace promptly.
  • Broken pieces sometimes melted/formed beads; annealing applied to beads too after the fact.

Radiation-dose interpretation (safety framing)

• Dose-equivalent readings in µSv/hr are reported for:
  • Large piece: ~5.5 µSv/hr
  • Smaller bead: ~1.3 µSv/hr
• A comparison is made to medical imaging exposure rates (described as roughly like dental X-rays over time).
• Main guidance: generally safe for occasional handling, but not suitable for constant carrying close to the body (e.g., pockets).

---

Researchers / sources featured

• Cody’sLab (Cody) – mentioned as a source advising against publishing uranium refinement instructions online.
• Applied Science (Ben) – provides methods/tips for glassmaking.
• How to Make Everything (Andy) – provides additional glassmaking tips.
• Canadian Nuclear Association – cited for converting/dose interpretation guidance (used with µSv/hr interpretation).