- Borosilicate 3.3 glass test tubes with screw cap
- Capacity 15ml
- Length x OD: 125 x 16mm
- Round bottom
- Includes Bakelite screw cap with rubber liner
- Excellent resistance to heat and chemicals
- Tube and cap are autoclavable
OVERVIEW :
GWSI 15 ml round bottom test tubes with screw caps provide ultra-micro sealed capability for working with extremely precious, rare, or severely limited samples requiring leak-tight containment at capillary scale. Crafted from borosilicate 3.3 glass, they deliver high thermal shock resistance and chemical inertness in the most compact sealed format available. The secure screw cap enables reliable sealing for transport and storage, while the 15 ml capacity offers maximum material conservation for irreplaceable samples and ultra-micro sealed reactions.
HISTORY:
The 15 ml sealed test tube emerged from the need to work at capillary scale with extraordinarily precious materials while maintaining sealed protection. Traditional sealed vessels, even at 10 ml, consumed too much material for certain ultra-rare natural products, expensive synthesized intermediates, or irreplaceable clinical specimens. This ultra-micro sealed size proved essential for situations where sample availability was measured in microliters, yet leak-tight containment remained critical for transport, incubation, or sealed micro-reactions.
APPLICATIONS:
– Pharmaceutical labs — capillary-scale sealed reactions with irreplaceable intermediates, ultra-micro sample transport, and precious compound storage
– Biotech facilities— sealed analysis of extremely limited biological samples, trace enzyme assays with precious substrates, and rare specimen transport
– Clinical laboratories— testing of irreplaceable clinical specimens requiring sealed protection, micro-diagnostic sealed procedures, and ultra-trace sample storage
– University teaching labs — advanced micro-chemistry sealed demonstrations showing extreme conservation with leak-tight containment
– College research groups — work with rare natural products, expensive catalysts, or limited synthetic intermediates at capillary scale with sealed protection
– School science labs — specialized demonstrations of maximum efficiency and conservation with sealed containment using minimal materials
– Industrial QC labs — ultra-micro sealed analysis with extremely expensive reference standards and precious quality control samples
MANUFACTURING PROCESS:
GWSI manufactures 15 ml round bottom test tubes with screw caps by melting borosilicate 3.3 glass at 1,650°C and forming the ultra-compact cylindrical body and round bottom through expert hand-blowing or ultra-precision automated molding. The screw thread requires exceptional craftsmanship to form at such a small opening while maintaining precise dimensions for leak-tight cap engagement. Extreme precision in wall thickness control ensures structural integrity, followed by carefully controlled annealing to eliminate stress in the miniature sealed form.
TESTING PROCESS:
Manual inspection under magnification verifies wall thickness uniformity, round bottom geometry, thread quality, and dimensional accuracy on every tube. Automated polarization stress testing then scans the glass for residual strain that could cause failure during sealed applications. Sample tubes from each batch undergo pressure testing to verify leak-tight sealing performance, and thread engagement is validated with master gauges to ensure reliable closure at this ultra-micro scale.
PRINTING PROCESS:
Volume markings and identification areas are silkscreened onto the tube surface using ceramic glass inks formulated for borosilicate compatibility. The tubes enter high-temperature kilns where ceramic glass fusing permanently bonds the ink into the glass matrix. This creates durable, legible markings that resist chemical attack, repeated heating, and autoclaving—essential for tubes used in ultra-micro sealed applications with precious samples.
PACKAGING PROCESS:
Final sorting under magnification removes any tubes with wall defects, thread imperfections, round bottom irregularities, or surface blemishes. Approved tubes are individually wrapped or nested in specialized ultra-micro compartmentalized trays to prevent contact damage during shipping. They’re packed in heavy-duty double-wall corrugated boxes with shock-absorbing dividers, suitable for domestic distribution or international export to laboratories specializing in precious sample work.
MAINTENANCE & SAFETY :
– Clean immediately after use with capillary-volume solvents or detergents; specialized micro-brushes are essential for thorough interior cleaning
– Autoclave at 121°C / 15 psi with caps loosened to prevent pressure buildup; tubes are fully autoclavable through repeated sterilization cycles
– Never heat-sealed tubes— pressure buildup can cause dangerous explosion; always loosen or remove caps before any heating
– Inspect under magnification before each use for any defects; the ultra-compact dimensions concentrate stress and demand flawless condition
– Handle with specialized micro-tools and techniques; standard laboratory equipment is too large for safe manipulation of this size
– Store in specialized micro-tube racks or vial storage systems; standard racks cannot securely hold these ultra-compact sealed tubes
Manufactured by GWSI Glass Lab — Ambala, Haryana, India (The Science City)