# Borosilicate 3.3 Optical Sight Windows Boiler Furnace Observation Panels Heat Resistant 450C Thermal Shock Low Expansion Polished Industrial Instrument Glass

> Borosilicate 3.3 Optical Sight Windows Boiler Furnace Observation Panels Heat Resistant 450C Thermal Shock Low Expansion Polished Industrial Instrument…

- Page: https://machiningglass.com/products/borosilicate-3-3-optical-sight-windows-boiler-furnace-observation-panels-heat-resistant-450c-thermal-shock-low-expansion-polished-industrial-instrument-glass/
- SKU: MG-A4DA39
- Category: LED / OLED Cover Glass > Display, Touchscreen & Instrument Cover Glass
- Image: https://machiningglass.com/wp-content/uploads/2026/10/Borosilicate-3-3-Optical-Sight-Windows-Boiler-Furnace-Observation-Panels-Heat-Resistant-450C-Thermal-Shock-Low-Expansion-Polished-Industrial-Instrument-Glass.webp
- Updated: 2026-10-24

Product type: Optical Glass. Application: Sight glass, level gauge, boiler/furnace observa. Model: HT-OPG. Function: Optical Function, Thermal Function, Mechanics and Mechanical Function.

## Overview

The Borosilicate 3.3 Optical Sight Windows Boiler Furnace Observation Panels Heat Resistant 450C Thermal Shock Low Expansion Polished Industrial Instrument Glass is supplied as a display / touchscreen cover glass made from Optical/technical glass: soda-lime, high-alumina,. Listed geometry: size Custom, thickness 0.5-25mm (ultra-thin 0.5-1.1mm; borosilicate 1.5-2, round disc, square, rectangular, custom outline, s shape. It is used in Optical. Dimensions, material grade, coating and finish can be quoted to your drawing; the values above are the listed starting point.

## Specifications

| Parameter | Value |
| --- | --- |
| Material | Optical/technical glass: soda-lime, high-alumina, |
| Type | Optical Glass |
| Shape | Round disc, square, rectangular, custom outline, s |
| Size | Custom |
| Thickness | 0.5-25mm (ultra-thin 0.5-1.1mm; borosilicate 1.5-2 |
| Application | Optical |
| Usage | Sight glass, level gauge, boiler/furnace observa |
| Model NO. | HT-OPG |
| Structure | Solid |
| Moh's Hardness | 6 |
| Function | Optical Function, Thermal Function, Mechanics and Mechanical Function |
| Transparency | Transparent |
| Processing Method | CNC cutting, grinding, optical polishing, drilling |
| Preparation Process | Fusion Method |
| Color | Clear, ultra-clear |
| Custom Attribute: Coating | AR/AF |
| Place of Origin | Qingdao |
| Quality Control Process | Incoming Material Check |
| Certifications | ISO 9001 Quality Management System |
| Sea Freight | 25–40 days transit. Cost-efficient for bulk orders; FCL & LCL available. |
| Air Freight | 4–7 days transit. Perfect for urgent shipments. |
| International Express | 3–5 days transit. Door-to-door service by DHL, FedEx, UPS, optimal for samples and small packages. |
| Key Production Equipment | - CNC glass-cutting and shaping machines |
| Custom Attribute | Coating: AR/AF |
| Supplier | Qingdao Hitech Glass Co.,Ltd |

## Technical data

|   |   |   |
| --- | --- | --- |
| Application | Recommended Material | Typical Form and Processing |
| Cover panels and touch surfaces | Ultra-thin soda-lime / high-alumina OG02 | 0.5-1.1mm, chemical strengthen, silk-screen border |
| Camera and sensor windows | Ultra-thin borosilicate / high-alumina OG02 | AR/AF coated, precision cut, polished edge |
| Optical substrates for coating | Ultra-thin borosilicate 3.3 OG02 | 0.5-1.1mm, polished, low inclusion |
| Boiler and furnace observation | Borosilicate 3.3 OG03 | Round disc, 450C, DIN sight-glass size |
| Tank and boiler level gauges | Borosilicate OG03 / fused quartz OG04 | Long strip or disc, ground and polished |
| Oven and appliance sight windows | Borosilicate 3.3 OG03 | 3-5mm, optional heat-bend and black border |
| High-temperature furnace windows | Fused quartz OG04 | To about 1100C, JGS2/JGS3, polished |
| UV and IR optical windows | Fused quartz JGS1/JGS2/JGS3 OG04 | Wavelength grade, optical polish |
| Laboratory and spectrometer parts | Fused quartz OG04 | Discs, plates, cuvette and gauge blanks |
| Semiconductor process carriers | High-purity fused quartz OG04 | Custom machined shapes, acid resistant |
| High-pressure vessel viewports | Sapphire OG05 / quartz OG04 | Thick disc, flange fit, rating per assembly |
| HF and strong-acid reactors | Single-crystal sapphire OG05 | Acid-inert window, polished |
| Vacuum chamber and R and D viewports | Sapphire OG05 | UV-IR transmitting, scratch proof |

## What to specify when you request a quote

- **Glass type and thickness** — listed as “Optical/technical glass: soda-lime, high-alumina,”; name the glass (soda-lime, aluminosilicate, borosilicate) and thickness.
- **Strengthening** — state thermal tempering or chemical strengthening and the required surface compression or impact rating.
- **Printing and coatings** — listed as “Sight glass, level gauge, boiler/furnace observa”; list silk-screen colours, windows, and any AR / AG / AF coating.
- **Outline and edges** — listed as “Round disc, square, rectangular, custom outline, s”; send a drawing with cut-outs, holes and edge finish.
- **Optical requirements** — give transmission, haze or gloss targets for the viewing area.

## Engineering guides for this part

For material grades and coating options, see [AR-Coated Glass Materials for High-Transmission Optical Parts](https://machiningglass.com/materials/ar-coated-glass-materials-for-high-transmission-optical-parts/). How parts like this are machined and finished is covered in [Flat Glass Polishing Process for Precision Substrates](https://machiningglass.com/capabilities/flat-glass-polishing-process-for-precision-substrates/). For an application example, read [AR Glass for Appliance Touch Screens: Selection & Integration](https://machiningglass.com/applications/ar-glass-for-appliance-touch-screens-selection-integration/). Before sending a drawing, check [Quartz Glass Manufacturing: Controlling Thermal Conductivity in Fused Silica](https://machiningglass.com/resources/quartz-glass-manufacturing-controlling-thermal-conductivity-in-fused-silica/). A related standard product is [AR Anti-Reflection Optical Window](https://machiningglass.com/products/ar-anti-reflection-optical-window/).

## FAQ

### What is the Borosilicate 3.3 Optical Sight Windows Boiler Furnace Observation Panels Heat Resistant 450C Thermal Shock Low Expansion Polished Industrial Instrument Glass made of?

It is listed as Optical/technical glass: soda-lime, high-alumina,. Other grades can be quoted if your application needs different transmission, thermal or chemical properties.

### What sizes and thicknesses are available?

The listing gives size Custom, thickness 0.5-25mm (ultra-thin 0.5-1.1mm; borosilicate 1.5-2. Custom outlines and thicknesses are made to drawing; state the tolerance you need.

### Where is this display / touchscreen cover glass used?

Listed applications: Optical.

### What should I include in a quote request?

Include glass type and thickness, strengthening, printing and coatings, outline and edges and optical requirements, plus quantity and a drawing if the part is custom.

## Request a quote

Send drawings, tolerances and quantity: https://machiningglass.com/contact/?rfq_product_id=9305#mg-rfq

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Source: Custom Precision Glass Machining — https://machiningglass.com/