Technical Guide to Ordering Glass – What You Need to Know

At The Glass Shop Online we want every order to be perfect first time. Here is a clear, practical guide to the key technical points you should be aware of when ordering made-to-measure glass.

Glass Specification

The final specification for your glass project is ultimately your responsibility (or that of your architect/installer). We will always advise based on our manufacturing capabilities, but any changes we suggest are not a substitute for a full structural assessment.

Lead Times

All glass is made to order. While we quote lead times in good faith, occasional manufacturing issues (especially during toughening or bending) can cause small delays. We will always keep you fully informed.

Holes in Toughened Glass

The position of holes is critical in toughened glass to avoid stress and breakage. Please follow these guidelines:

• Minimum distance between holes = 4 × glass thickness
• Hole diameter must be at least equal to the glass thickness
• Minimum distance from corner of glass to edge of hole = 4 × glass thickness
• Minimum distance from edge of glass to edge of hole = 1.5 × glass thickness
• Position tolerance is normally ±1 mm to ±3 mm (depending on thickness)

If a hole needs to be closer than recommended, we may add a small saw cut to relieve stress.

Corners

When glass is processed the corners are sharp unless you request otherwise. You can choose:

• Standard (sharp) corners
• Dubbed corners (slightly sanded flat – dull finish)
• Radius corners (smooth rounded and polished)

Please state your preference when ordering.

Drawings, Templates & Cut-Outs

• For any shaped glass we need fully dimensioned drawings (CAD or DXF format preferred).
• Physical templates must be exact finished size with holes/cut-outs in the correct position and clearly labelled.
• Internal cut-outs or corners will have a minimum radius applied (6 mm ground or 13 mm polished finish). Please specify which you prefer.

Edgework & Polishing

Our polishing is done to a very high standard (machine finished). Polished safety edges are included free of charge as standard on the majority of our products. Please advise at order point if you require a specific finish.

Other Important Technical Notes

• Misalignment – Edge slip of up to 3mm between glass components is acceptable for manufactured laminated products.
• Back Painted / Ceramic Glass – We recommend using low iron glass for painted products so colours appear true. Colour matching to existing items is not guaranteed.
• Toughening Stamp – All toughened and fire-rated glass will have a kitemark (approx 30mm × 30mm) in one corner. Edge stamping can be requested.
• Thermal Strength – Annealed glass can withstand up to 40°C. Toughened glass can withstand up to 300°C.

Nickel Sulphide Inclusions (Spontaneous Breakage)

On very rare occasions toughened glass can break spontaneously due to tiny nickel sulphide inclusions. Heat-soak testing greatly reduces this risk. Please ask us if you would like this option.

Storage & Handling

• Store glass on edge, in dry conditions, using soft spacers.
• Always use gloves and protective equipment when handling.
• Protect edges from impact.

Maintenance

Clean installed glass regularly with a good-quality, non-abrasive glass cleaner. Avoid oil-based products.

Re-Orders

Slight colour variations can occur between batches. We will always try to match the original glass where possible.