The four glass families we work with, side-by-side. Pick by thermal envelope, chemical environment, optical needs, and budget — or send us the application and we'll recommend.
Reference values from supplier MTRs and ASTM/ISO test methods. Treat as typical, not as a substitute for the COC on your specific lot.
| Property | Boro 3.3 | Boro 5.0 (USP I) | Fused Quartz | Soda-Lime |
|---|---|---|---|---|
| CTE (20–300 °C) | 3.3 × 10⁻⁶ /K | 5.0 × 10⁻⁶ /K | 0.55 × 10⁻⁶ /K | 9.2 × 10⁻⁶ /K |
| Working point | 1,260 °C | 1,165 °C | 1,720 °C | 1,000 °C |
| Annealing point | 560 °C | 555 °C | 1,140 °C | 545 °C |
| Strain point | 510 °C | 505 °C | 1,070 °C | 505 °C |
| Tmax — continuous service | 500 °C | 450 °C | 1,100 °C | 350 °C |
| Thermal shock ΔT | 160 K | 90 K | 1,000 K | 40 K |
| Density | 2.23 g/cm³ | 2.34 g/cm³ | 2.20 g/cm³ | 2.50 g/cm³ |
| UV cutoff (1 mm) | 310 nm | 295 nm | 170 nm | 340 nm |
| Acid resistance (DIN 12116) | Class 1 | Class 1 | Class 1 | Class 2 |
| Hydrolytic class (ISO 720) | HGB 1 | HGB 1 (Type I) | HGB 1 | HGB 3 |
CTE: coefficient of linear thermal expansion. Tmax: temperature for continuous service without measurable creep or devitrification. Thermal shock: instantaneous quench tolerance, plunged hot piece into 25 °C water. UV cutoff: wavelength at which transmission falls below 50% through 1 mm wall.
Practical rules of thumb. When in doubt, send the application — we'll recommend.
The right answer for ~80% of laboratory pieces. Excellent thermal shock, broad chemical resistance, easy to work, predictable to anneal. Schott Duran®, Corning Pyrex®, and equivalents.
USP <660> Type I container glass. Ampoules, vials, primary packaging where hydrolytic resistance and alkali release must meet pharmacopeial limits. Slightly less thermal shock than 3.3.
Continuous service to 1,100 °C. UV transmission below 200 nm. Required for spectroscopy cuvettes, semiconductor process tubes, ICP torches, and any continuous high-temperature work.
Storage bottles, wash bottles, non-thermal glassware. Cheaper. Do not use anywhere thermal cycling, organic solvents at elevated temperature, or pharmacopeial container specs apply.
All to ASTM E676 / DIN 12242. Other sizes (ball-and-socket, O-ring, threaded GL) on request.
| Designation | Top OD | Length | Common use |
|---|---|---|---|
| 10/18 | 10.0 mm | 18 mm | Micro-scale glassware, small Schlenk |
| 14/20 | 14.5 mm | 20 mm | Schlenk, small condensers, micro-RB |
| 19/22 | 18.8 mm | 22 mm | Educational, organic micro-prep |
| 24/40 | 24.0 mm | 40 mm | Default for most US synthesis glassware |
| 29/42 | 29.2 mm | 42 mm | EU-standard synthesis (DIN 12242) |
| 34/45 | 34.5 mm | 45 mm | 3L–5L flasks, mid-scale reactor adaptors |
| 45/50 | 45.0 mm | 50 mm | Large flasks, reactor center-port |
| 55/50 | 55.0 mm | 50 mm | Large reactor inlets, distillation heads |
| 71/60 | 71.0 mm | 60 mm | Pilot-scale reactor center-port |
| 103/60 | 103.0 mm | 60 mm | 50 L+ pilot reactor lid joint |
When you say "Class A volumetric to ASTM E288," we build it to the published method. When you cite a customer print number, we build to your print and ignore the standard. Tell us which.
| Standard | Issuer | Scope |
|---|---|---|
| ASTM E287 | ASTM International | Burettes, Class A & B — volumetric tolerance and graduation |
| ASTM E288 | ASTM International | Volumetric flasks — Class A & B specifications |
| ASTM E542 | ASTM International | Calibration of laboratory volumetric apparatus |
| ASTM E676 | ASTM International | Standard taper ground glass joints |
| ASTM E960 | ASTM International | Beakers — laboratory glass, low-form Griffin |
| ASTM E969 | ASTM International | Volumetric (transfer) pipettes — Class A & B |
| ASTM E1404 | ASTM International | Erlenmeyer flasks — narrow-mouth, ground-joint or plain |
| ISO 720 | ISO | Hydrolytic resistance of glass grains at 121 °C (HGB classification) |
| ISO 4799 | ISO | Reflux and distillation condensers — performance and dimensions |
| USP <660> | USP | Pharmaceutical container glass — Type I/II/III determination |
| USP <1660> | USP | Evaluation of inner surface durability of glass containers |
| DIN 12116 | DIN | Acid resistance classification of glass surfaces |
| DIN 12242 | DIN | Interchangeable conical ground joints (EU standard) |
| DIN 12338 | DIN | Crystallizing dishes |
| DIN 12576 | DIN | Liebig & Allihn condensers — dimensions and joints |
| JIS R 3503 | JIS (Japan) | Glass apparatus for chemical analysis |
Tell us the chemistry, the temperature window, and the optical requirement. We'll come back with the right glass — or tell you when it doesn't exist.