Technical Details - StewartFloat® Tin Bath

Benefits to the Investor

StewartFloat® tin baths boost yields, reduce defects, and produce better optical quality glass than other suppliers' baths. Our experience gained over more than thirty years constructing and operating tin baths enables us to provide customers with exceptional build quality, rapid construction, and economical pricing.

We provide expert services in tin bath construction, heat-up, and operations to ensure plant profitability. Investors utilizing StewartFloat® tin baths and Stewart operating principles will earn industry-leading returns on investment with swift payback.

StewartFloat® tin baths produce glass between 0.4 mm - 25 mm thickness with proper configuration.

Stewart Engineers Tin Bath History

Stewart Engineers built the first StewartFloat® tin bath in 1992, and it continues to produce 2mm glass today. In 1997, Stewart Engineers successfully commissioned a StewartFloat® bath in Southeast Asia that is still producing ultra-thin glass down to 0.55 mm. Stewart Engineers has equipped the worldwide float glass market for 36 years with 23 tin baths, thus providing immense expertise to design a StewartFloat® tin bath to fulfill your market demands.

All 23 StewartFloat® tin baths are still operational to date.

Top roll machines, heating elements, and molten glass in StewartFloat® tin bath
Top roll machines, heating elements, and molten glass in StewartFloat® tin bath

StewartFloat® Specialty Technology

StewartFloat® tin baths eliminate defects by atmospheric control:

  • Nitrogen and hydrogen purity and blending ratio
  • Gas introduction location and venting
  • Exit curtain sealing
  • Bath pressure control

Stewart Engineers provides best practice methods for temperature regulation:

  • Cross-ribbon temperature control to stringent coating requirements
  • Optimization of bath temperature profile for optical quality
  • Precise temperature control at the coater for chemical efficiency

StewartFloat® electrical bus bars enter through the top of the upper casing:

  • Reducing cable overheating
  • Streamlining tin bath appearance

StewartFloat® stabilizes glass flow by employing:

  • Automated tweel control
  • Precise loop-tuning for canal temperature and glass level control
  • Top-roll operating methods for ribbon stability

Customized Design Process

The StewartFloat® tin bath design allows for immediate and/or future installations of CVD glass coating equipment without the need for process modification or process downtime.

Stewart Engineers also utilizes 3D CAD modeling of the bath to achieve:

Looking upstream of a StewartFloat® tin bath. End coolers, distant top roll machines, and structural steel are visible
Looking upstream of a StewartFloat® tin bath. End coolers, distant top roll machines, and structural steel are visible

Designed for Reliability

Soda can leach from glass into tin causing nepheline formation on top of bath bottom blocks. Nepheline has a different coefficient of expansion, causing it to peel off in large sheets resulting in ribbon loss. Stewart Engineers selects bath bottom blocks that resist nepheline formation.

Our proprietary design avoids the formation of bath bottom bubbles, a common glass defect, thereby eliminating the need for costly vacuum points on the bottom of the tin bath.

The electrical resistance of bath heating elements increases at sustained peak power output. Stewart Engineers prolongs element lifespan by designing for low power density under normal operations.

Stewart Engineers has designed the bath exit end, the dross box, to reduce glass breakage during glass lift-out. It also limits ingress of contaminates such as oxygen and sulfur in the bath atmosphere.

StewartFloat® Tin Bath Downloads



Over the past 36 years, 23 proven StewartFloat® tin baths have been installed worldwide, all of which are operational today. StewartFloat® tin baths are producing glass as thin as...

Float Glass Applications

Float Glass Applications

Float glass applications include architectural, automotive, solar, electronics, appliance, and furniture. Stewart Engineers designs industry-leading equipment for each customer’s desired applications...