What is float glass? Types, sizes and buying specifications.

1 · What float glass is

Float glass is flat glass formed by floating molten glass over a bath of molten tin. Because the glass spreads on a liquid metal surface, both faces come out flat, parallel and fire-finished without grinding or polishing. It is the base product behind most architectural, industrial and processed glass in the market.

2 · How the float process works

Raw materials (silica sand, soda ash, limestone, dolomite and cullet) melt at around 1,500°C, flow onto the tin bath where thickness is set by speed and top-roller control, then travel through an annealing lehr that cools the ribbon slowly to relieve internal stress. The ribbon is inspected, scored and snapped into sheets at the cold end. Line capability, not the process name, decides which thicknesses, tints and coatings a given manufacturer can actually run.

3 · Clear, low-iron, tinted and coated

• Clear float, the standard product; slight green edge tint from iron content.
• Low-iron / ultra-clear, reduced iron for higher transmission and neutral edges; the basis for display, furniture and solar applications.
• Tinted, body-tinted grey, bronze, green or blue for solar control and appearance, subject to the line's colour campaigns.
• Coated, reflective or low-emissivity coatings applied on-line or off-line; availability is line-specific and should be treated as a per-manufacturer question, not a catalogue assumption.

4 · Standard and jumbo formats

Common trade sizes include 2140×3300 mm and 2440×3660 mm, with jumbo sheets at 3210×6000 mm and similar. Format drives everything downstream: cutting yield, rack type, container loading and the equipment a processor needs at destination. State the format you cut on, not just "jumbo".

5 · Thickness selection

Commercial float ranges from 2 mm to 19 mm, with 3 to 12 mm carrying most trade volume. Thickness follows the application and downstream processing: tempering, laminating and IGU lines each have their own preferred inputs. Specify nominal thickness with the tolerance standard you work to, and say if the glass will be heat-treated afterwards.

6 · Annealed glass versus downstream processing

Float glass leaves the line annealed. Tempering, heat-strengthening, laminating, coating and insulating are downstream steps, done either by the float producer's processing lines or by the buyer. Be explicit about who processes: it changes the specification, the packing and the inspection scope.

7 · Common quality checks

Visual and dimensional inspection against the agreed standard: bubbles, inclusions, scratches and tin-side marks per the defect-size and frequency table; thickness and size tolerances; squareness; edge condition. Optical distortion is checked where the application demands it. The workable approach is to agree the inspection standard and sampling plan in the contract, then inspect to that scope, not to adjectives.

8 · Export packing and container loading

Float glass ships in wooden or steel end-cap crates, interleaved with powder or paper, loaded in containers with inflatable dunnage and bracing certified for glass cargo. Jumbo sheets need open-top or specialised in-container racks. Packing method, crate marking and loading photos belong in the contract and the shipment file.

9 · Documents for international supply

Commercial invoice, packing list with crate-level detail, certificate of origin, bill of lading, the manufacturer's quality certificate for the batch, inspection record per the agreed scope, and insurance where the Incoterm calls for it. Destination-specific requirements are confirmed per transaction.

10 · What a float-glass RFQ must state

The TRX-FG product page shows the configurations Torix quotes and how approval runs from specification to shipment.