Borosilicate glass 3.3 for boiler sight glass, gauge glass, and industrial viewing applications, offering excellent thermal stability and thermal shock resistance.
Thickness: 2–30 mm
Max. Working Temperature: <550°C
Customization: Size, shape & thickness
Borosilicate sight glass is a heat-resistant glass product designed for applications requiring clear visibility, thermal stability, and resistance to temperature changes. Made from borosilicate glass 3.3, it can be processed into sight glass, gauge glass, viewing windows, and customized glass components for boilers and other industrial equipment.
With a low coefficient of thermal expansion and good thermal shock resistance, borosilicate glass is suitable for applications where the glass may be exposed to elevated temperatures or rapid temperature changes. Custom sizes, thicknesses, and shapes are available according to equipment specifications and installation requirements.
| Property | Specification |
| Material | Borosilicate Glass 3.3 |
| Product Type | Sight Glass / Gauge Glass / Glass Sheet |
| Size & Shape | Customized |
| Maximum Working Temperature | <550°C |
| Available Thickness | 2–30 mm |
| Coefficient of Thermal Expansion | 3.3 ± 0.1 × 10⁻⁶ (20–300°C) |
| Softening Point | 820 ± 10°C |
| Thermal Shock Resistance | ≥125 K |
| Refractive Index (nd) | 1.47384 |
| Light Transmission | 92% for thickness ≤4 mm; 91% for thickness ≥5 mm |
Borosilicate glass 3.3 combines transparency with good thermal stability, making it suitable for selected industrial applications where clear visual observation is required.
Its low coefficient of thermal expansion helps the glass withstand temperature changes, while its high light transmission provides good visibility through the glass. The material can be manufactured into different shapes and dimensions according to the design of the equipment.
Key characteristics include:
· Low coefficient of thermal expansion
· Good thermal shock resistance
· High temperature stability
· High light transmission
· Good chemical durability
· Customized dimensions and thicknesses
· Suitable for industrial sight and viewing applications
Borosilicate glass can be processed into sight glass and gauge glass for boilers and industrial equipment where visual monitoring is required. Depending on the equipment design, the glass can be supplied in different shapes, dimensions, and thicknesses for viewing or level indication.
Its thermal stability and resistance to temperature changes make it suitable for selected boiler applications where clear and reliable visual observation is required.
Boiler Reflex Gauge Glass
Borosilicate glass can be manufactured for reflex gauge glass applications used for visual liquid-level indication. The glass can be produced according to the required dimensions, thickness, shape, and processing specifications.
For customized boiler reflex gauge glass, customers can provide drawings, dimensions, or equipment specifications for production evaluation.
High-Pressure Boiler Sight Glass
For high-pressure boiler applications, glass selection should take into account the operating temperature, pressure, glass dimensions, thickness, mounting method, and equipment design.
Our borosilicate glass can be customized according to the technical requirements of the application. Customers are encouraged to provide the operating conditions and drawings so that the appropriate glass specification can be evaluated.
Qingdao Vatti Glass provides customized borosilicate glass for different industrial applications. Glass dimensions, thicknesses, and shapes can be produced according to customer requirements.
Customization options may include:
· Custom length and width
· Custom diameter
· Custom thickness from 2–30 mm
· Round or rectangular shapes
· Customized glass plates
· Edge processing according to requirements
· OEM production based on drawings or specifications
For custom projects, customers can send drawings, dimensions, required thickness, application conditions, and quantity for evaluation and quotation.
In addition to boiler sight glass and gauge glass, borosilicate glass can be used in other equipment where thermal stability and visual observation are required.
Industrial Viewing Windows
Borosilicate glass can be used as a viewing window in industrial equipment where clear visibility and resistance to temperature changes are required.
Heating Equipment
The glass can be used for selected heating equipment and systems where transparent, heat-resistant glass is required for visual observation.
Process Equipment
Borosilicate glass can be processed into viewing components for industrial process equipment, subject to the required operating conditions and installation specifications.
Laboratory and Inspection Equipment
Its transparency and thermal stability make borosilicate glass suitable for selected laboratory and inspection applications that require heat-resistant viewing components.
Qingdao Vatti Glass Co., Ltd. manufactures and supplies borosilicate glass products for industrial and commercial applications. Our product range includes borosilicate sight glass, gauge glass, viewing windows, and customized glass components.
We provide customized dimensions, thicknesses, and shapes according to customer requirements. Our production and quality control processes include dimensional inspection and quality checks to help ensure that finished glass meets the required specifications.
We also support OEM requirements and customized orders based on customer drawings, dimensions, and technical specifications.
With experience in international glass supply, our products are exported to customers in Europe, North America, Asia, Africa, and other overseas markets.
1.What is borosilicate sight glass?
Borosilicate sight glass is a transparent glass component made from borosilicate glass and used for visual observation in industrial equipment. It can be manufactured in different shapes and dimensions for sight glass, gauge glass, and viewing window applications.
2.Can borosilicate glass be used for boilers?
Yes. Borosilicate glass can be used for selected boiler sight glass and gauge glass applications when its temperature resistance, thermal shock resistance, dimensions, and other properties meet the equipment requirements.
3.Can this glass be used as boiler reflex gauge glass?
Yes. Borosilicate glass can be manufactured for reflex gauge glass applications according to the required dimensions, thickness, shape, and processing specifications.
4.What is the maximum working temperature?
The specified maximum working temperature of this product is below 550°C. The actual suitable operating temperature depends on the glass dimensions, thickness, installation conditions, pressure, and application environment.
5.What thicknesses are available?
The available thickness range is 2–30 mm. Customized thickness requirements can be evaluated according to the application and production specifications.
6.Can you make custom-size borosilicate sight glass?
Yes. Custom sizes and shapes are available. Customers can provide drawings, dimensions, thickness requirements, and application details for evaluation.
7.Can you manufacture round gauge glass?
Yes. Round borosilicate glass can be produced according to specified diameters and thicknesses, subject to the application and production requirements.
8.What is borosilicate glass 3.3?
Borosilicate glass 3.3 is a type of borosilicate glass characterized by a low coefficient of thermal expansion. It is commonly selected for applications requiring thermal stability, transparency, and resistance to temperature changes.
Have a specific sight glass or gauge glass requirement? Share your dimensions, thickness, shape, drawing, or technical specifications with our team.
We will review your requirements and help confirm the appropriate glass specification for your application.