Description
Borosilicate glass (borofloat, borosilicate flat glass)
Borosilicate glass, most common applications: technical applications requiring better resistance to heat (max +500 Celsius < 10 hours or +450 Celsius more than 10 hours, maximum temperature difference inside the glass 300K) or acidic or alkaline substances, e.g. inspection hatch glass, 3D printer levels, etc. # borofloat price
Borosilicate glass has a harder surface than ordinary float glass, which means that it also has better wear resistance and mechanical resistance than ordinary float glass.
Borosilicate glass is clear and more colourless than ordinary construction glass.
We have the following borosilicate flat glasses in stock:
- Schott Borofloat 2.0mm
- Thickness tolerance -+0.05mm
- Schott Borofloat 3.8mm
- Thickness tolerance -+0.2mm
- Schott Borofloat 6.5mm
- Thickness tolerance -+0.2mm
- Schott Borofloat 11mm
- Thickness tolerance -+0.3mm
- Schott Borofloat 15mm
- Thickness tolerance -+0.4mm
- Schott Borofloat 19mm
- Thickness tolerance -+0.5mm
Note! For the outer dimensions of borosilicate glass made to specification, we use the normal dimensional tolerances for building glass in accordance with our delivery terms. If you need glass made to any other dimensional tolerance (e.g. +-0.7, +-0.5 or +-0.1 etc.), please contact our sales department.
Schott Borofloat glass
- thermal properties (PDF)
- mechanical properties (PDF)
- optical characteristics (PDF)
- chemical properties (PDF)
- general characteristics (PDF)
Borosilicate glass is not suitable for fireplace glass. Suitable glass for fireplaces is ceramic fire-resistant glass.
Edge treatment (arrising, grinding, polishing..)
If the edges of the glass remain visible after installation, we recommend that you also apply a edge polish to the glass from the edges menu. In this case, the sharp edges of the glass are grinded clean and polished. ready for presentation. Edge grinding also slightly increases the bending resistance of the glass. To add to the appearance, you can also choose to have the glass surface faceted at the edge or 45-degree faceted. When facet grinding glasses, if all corners of the glass are rounded with less than 11mm of angular curvature, the facet grinding is done in a straight line and does not follow the angular curvature. Otherwise, the facet is performed on a CNC machine to follow the edge line of the glass, including the rounding.
When ordering borosilicate glass - if you do not choose edge grinding (cut only), we will in any case roughly strip the edges of the glass to blunt the sharp edges.
You can get borosilicate glasses cut to any of the above glass shapes (select shape), also available with holes drilled.
If you need radius corners - Examples of the size of radiuses: R or radius, which is the size of the circle the angular rotation is part of. Examples of what corner spinning can be compared to:
- The diameter of a long-playing LP is about 300mm, i.e. radius R=150mm
- The diameter of the CD is 120mm, i.e. radius R=60mm
- The diameter of a 2 euro coin is about 25mm, i.e. radius R=12.5mm
- The diameter of a 10 ct coin is about 20mm, i.e. radius R=10mm
- 3mm rounding (R3) the rounding is just visible to the eye from the corner of the round, but the shape of the glass is not yet substantially changed
- The 1mm rounding (R1) doesn't look much like a rounded corner, but feeling it with your fingertip you can feel that the sharpness has just about disappeared.
Drilling a hole in the glass - you can also order holes to be drilled in the glass to your desired location. There are certain regularities in where holes can be drilled in the glass. For example, each glass thickness has its own minimum distances, the distance between the edge of a hole and, for example, the edge of the glass, the corner of the glass or another hole. These distances are larger in tempered glass than in untempered glass, and the distances increase with the thickness of the glass. There is also a minimum hole diameter depending on the glass thickness.
- Our calculator always automatically checks that these minimum distances are met and that the hole is not too small for the glass thickness.
- The holes are always rough-edged, i.e. the holes are supposed to go "hidden".
- 6-40mm holes are usually drilled with diamond drills and holes over 40mm are either drilled or machined with CNC machines.
- There is no upper limit to the size of the hole, we can machine almost any size hole in the glass
- The holes can also be flush with the edges, i.e. make a so-called. half e.g. for cable penetrations, etc. or fireplace glass against a round fireplace
- The holes cannot be too close together, but the holes can partially overlap (min 1/3 part) - this will give you longer gaps. (Hole spacers may be machined straight if production possibilities so require)
- If possible, always try to use the same hole size (cheaper)
Please note that borosilicate glass cannot temper (tempering occurs at high temperatures), so if you order glass with holes, you should be careful when tightening screws through the holes, for example.
If you have any questions, please contact customer services. We are happy to help!
# borofloat price price # schott borofloat 33
Frequently Asked Questions
What is BOROFLOAT® 33 borosilicate glass?
BOROFLOAT® 33 from SCHOTT AG is the world's first floated borosilicate flat glass. It combines superior quality and excellent flatness with outstanding thermal, optical, chemical and mechanical features. The chemical composition complies with DIN ISO 3585 and DIN EN 1748 T1 standards.
What's the difference between SCHOTT BOROFLOAT® 33 and generic borosilicate float glass?
SCHOTT BOROFLOAT® 33 is a certified quality product manufactured to strict DIN ISO 3585 and DIN EN 1748 T1 standards. SCHOTT's patented float process guarantees uniform thickness (±0.05mm tolerance), exceptional optical quality and surface flatness. Based on our testing of various generic borosilicate glasses, quality varies significantly - we've observed air bubbles, uneven surfaces and waviness in many alternatives, although their thermal properties may be adequate. Every batch of BOROFLOAT® 33 comes with a quality certificate ensuring consistently high standards.
What are the key thermal properties of BOROFLOAT® 33?
BOROFLOAT® 33 has exceptional thermal properties: Linear thermal expansion coefficient α₂₀/₃₀₀°C = 3.3 × 10⁻⁶ K⁻¹, transformation temperature Tg = 525°C, annealing point = 560°C, and softening point = 820°C. It withstands continuous temperatures up to 450°C. Thermal shock resistance (RTS) depends on thickness: 3.8mm = 175K, 6.5mm = 155K, 11mm = 142K.
Why choose BOROFLOAT® 33 for high-temperature applications?
BOROFLOAT® 33 excels in high-temperature applications due to its extremely low thermal expansion (3.3 × 10⁻⁶ K⁻¹), high thermal shock resistance (ΔT 140-175K depending on thickness), and continuous operating temperature up to 450°C. It withstands cracking significantly better than regular float glass - for comparison, standard soda-lime window glass has a thermal expansion coefficient of 9.0 × 10⁻⁶ K⁻¹ and thermal shock resistance of only about 40K.
What are the optical properties?
BOROFLOAT® 33 has excellent optical properties: Refractive index nd = 1.471, Abbe number νe = 65.41, exceptional transparency in visible and near IR & UV range. Transmittance reaches >90% in visible light (380-780nm) for standard thicknesses. Low inherent fluorescence and minimal solarization tendency.
What makes BOROFLOAT® 33 ideal for optical applications?
BOROFLOAT® 33 offers exceptional optical clarity with >90% transmittance in visible light, low fluorescence, minimal solarization, and excellent UV transmission. The refractive index of 1.471 and Abbe number of 65.41 make it perfect for precision optics, windows, and optical instruments.
Is the BOROFLOAT® 33 surface directly suitable for precision optics?
While SCHOTT's state-of-the-art float process produces an exceptionally flat and smooth surface that far exceeds standard flat glass quality, it's important to understand that a float surface is not the same as a nano-level polished optical surface. The float process delivers excellent quality for display glass, windows, laboratory use, and many industrial applications. However, if you require nanometer-precision polished surfaces for lasers or precision optics, you'll need specially optically processed glass. BOROFLOAT® 33 serves as an excellent substrate material for these demanding optical treatments.
What are the mechanical properties?
BOROFLOAT® 33 mechanical properties: Density ρ = 2.23 g/cm³, Young's modulus E = 63 GPa, Vickers hardness HV 0.1/20 = 6.2 GPa, and stress-optical coefficient K = 4.0 × 10⁻⁶ mm²/N. The glass shows excellent strength and durability for demanding applications.
How chemically resistant is BOROFLOAT® 33?
BOROFLOAT® 33 offers exceptional chemical resistance: Hydrolytic resistance class HGB 1 (according to ISO 719), acid resistance class 1 (according to DIN 12116), and alkali resistance class A2 (according to ISO 695). It withstands most acids, bases, and solvents exceptionally well.
What is the chemical composition?
BOROFLOAT® 33 chemical composition (typical values): SiO₂ 81%, B₂O₃ 13%, Na₂O + K₂O 4%, Al₂O₃ 2%. This unique borosilicate composition provides the exceptional thermal and chemical properties that make it superior to regular soda-lime glass.
What thicknesses are available?
We stock BOROFLOAT® 33 in thicknesses: 2mm, 3.8mm, 6.5mm, 11mm, 15mm and 19mm. All thicknesses can be custom cut to any shape or dimension. For special applications, other thicknesses may be available on request.
How is BOROFLOAT® 33 manufactured?
BOROFLOAT® 33 is manufactured using SCHOTT's proprietary float process - the world's first floated borosilicate glass. This process ensures exceptional flatness, uniform thickness, and consistent quality. The float process eliminates surface defects and provides superior optical quality compared to traditional glass forming methods.
What are the applications for BOROFLOAT® 33?
BOROFLOAT® 33 is versatile with numerous applications thanks to its thermal resistance. In 3D printing, it's a popular build plate material as its low thermal expansion (3.3 × 10⁻⁶ K⁻¹) keeps the surface flat during printing. Laboratories use it for test tubes, petri dishes, and reaction vessels due to its excellent chemical resistance (HGB 1 hydrolytic class). In optics, BOROFLOAT® 33 serves as protective windows with high transmittance (>90% in visible light) and UV transmission. LED lighting benefits from its ability to withstand continuous heat without yellowing. Industrial processes employ it as sight glasses up to 450°C. Microfluidics leverages its biocompatibility and smooth surface. In demanding applications like semiconductor photolithography and scientific instruments, BOROFLOAT® 33 is the standard choice for its technical properties and consistent quality.
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