Name: Subsea Aluminum Flange
Brand: Blu-Sub
SKU: BS-SSC-FLNGE-ALU-A1A1
Price: 49.95 CAD
Availability: InStock

$49.95

50 Units Available for Quick Ship - Ships in 1-2 Business Days

Additional Units Made to Order - Ships in 2-4 Weeks

Shipping calculated at checkout.

Size

85mm

115mm

165mm

The Blu-Sub Aluminum Flange is a critical sealing and structural component for building custom underwater enclosures using either Subsea Enclosure Acrylic Tubes or Subsea Enclosure Aluminum Tubes. This flange must be paired with a compatible end-cap, such as the Subsea Aluminum End-Cap or the Subsea Optical Dome End-Cap, to create a secure, watertight seal. Because neither the acrylic nor aluminum tubes have integrated sealing edges or O-ring grooves, the flange provides the essential interface required for proper enclosure assembly.

On the Subsea Enclosure Aluminum Tube, side-threaded locking ports on the flange interface directly with the tube, offering optional mechanical retention of the end cap and flange. This is especially beneficial for high-vibration conditions or when deploying vertically in tethered systems, where movement or pressurization cycles could otherwise dislodge unfastened components. The aluminum flange secures to the tube using four set screws that engage with these locking ports, providing added safety and reliability for demanding subsea applications.

The flange features a double-O-ring design at the tube connection, ensuring a strong and redundant seal between the flange and the enclosure tube. It also includes an integrated O-ring groove for the end-cap, creating a pressure-resistant barrier when the cap is installed. All required O-rings are included with the flange to support immediate installation without additional sealing components.

Once installed over the open end of the tube, the flange forms the mounting surface for the end-cap and houses precision-machined O-ring grooves that ensure a tight, pressure-resistant seal. Standardized screw hole patterns and integrated alignment features support modular builds by allowing reliable disassembly and reassembly. The anodized aluminum construction provides long-term resistance to corrosion and mechanical stress in subsea environments, making this flange suitable for sensor housings, ROV enclosures, data pods, and other marine electronics.

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Material	Anodized Aluminum
Weight	85 mm: 116 g 115 mm: 190 g 165 mm: 276 g
Color	Black
Depth Rating	1,000 m / 3,281 ft
Dimensions	Refer to technical specifications

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DESCRIPTION

Installation and Maintenance Tips: Whether using an aluminum or acrylic tube, it is critical to thoroughly lubricate all O-rings with a high-quality compound like O-Ring Lubricant – MOLYKOTE® 111 Compound before inserting the flange. Proper lubrication helps prevent damage to the O-rings, the flange, and the tube itself, and greatly reduces the risk of leaks. Do not attempt to force the flange into place if the O-rings are dry or not fully lubricated, as this can lead to deformation or tearing of the O-rings and may permanently mar the sealing surfaces.

If replacement is needed, additional O-rings can be purchased as an optional spare set. For hassle-free maintenance, we also offer the Subsea O-Ring Pick – 2x Set (Nylon), designed to safely and easily remove O-rings during servicing without scratching or damaging components.

Compatible with Subsea Aluminum & Acrylic Enclosure Tubes

Sold Separately

Subsea Enclosure Acrylic Tube
Lightweight, optically clear tube ideal for vision-enabled underwater systems. The Blu-Sub Aluminum Flange provides a precise sealing and mounting surface, allowing secure installation of optical dome or flat end-caps for reliable, leak-free operation. Well-suited for camera housings and scientific instruments where visibility and ease of access are critical.

Subsea Enclosure Aluminum Tube
Rugged, deep-rated tube built for demanding subsea and ROV applications. The Blu-Sub Aluminum Flange delivers robust sealing and structural strength in high-pressure environments, enabling modular assembly with end-caps and domes. Supports secure, serviceable connections for maintenance and future upgrades.

End-Cap Compatibility

Sold Separately

Subsea Aluminum End-Cap
Provides a rugged, pressure-rated seal for subsea enclosures. Requires the Blu-Sub Aluminum Flange for secure, watertight attachment to acrylic or aluminum tubes. Available in multiple diameters for modular housing builds.

Subsea Optical Dome End-Cap
High-clarity polycarbonate dome designed for underwater cameras and vision systems. Exclusively fits the 115 mm flange using the dedicated retaining ring. Delivers optical performance and leak-free integration at depth.

Alternative End-Cap Solutions (No Aluminum Flange Required)

Sold Separately

The following options do not require a separate flange assembly or aluminum end-cap, as each features an integral end-cap and flange built into a single unit. These are only available in 115 mm diameter.

Subsea Polymer Flange & End-Cap 115 mm: Lightweight and cost-effective option for shallow water use. Suitable for general-purpose enclosures up to 30 m / 98 ft depth.

Subsea Optical Glass Flange & End-Cap 115 mm: High-clarity flat glass window for optical sensors and imaging payloads. Offers superior pressure resistance compared to acrylic. Depth rated to 300 m / 984 ft.

Compatible with Electronic Tray Set for Enclosure Tube

Sold Separately

Electronic Tray Set for Enclosure Tube
Offers a structured and secure platform for mounting internal electronics, batteries, and PCB assemblies inside Blu-Sub enclosures. Designed for use with 85 mm, 115 mm, and 165 mm tubes, the tray system includes base mounts, shelf supports, and all required hardware. When used with the Subsea Aluminum Flange, the base mount attaches directly to the aluminum flange using screws—ensuring stable and precise support for internal components. Compatible with both acrylic and aluminum tubes, the tray system enables efficient internal layout of subsea electronics.

Electronic Tray Set for Enclosure Tube

SHIPPING LIST

1 x Flange
1 x Face Seal O-Ring
2 x Radial O-Rings

TECHNICAL SPECIFICATIONS

	85mm Flange	115mm Flange	165mm Flange
Outer Diameter A	85	115	165
Inner Size B	58.6	86	136.6
Overall Height C	32.5	32.5	32.5
Piston Diameter D	75.6	105.6	155.6
Piston Length E	26.5	26.5	26.5
Inner Mounting Hole Circle F	65	93	144
Inner Mounting Hole G	M3	M3	M3
Maximum Internal Diameter H	68	95.5	145
Side-threaded Hole I	M3	M3	M3

Measurements are in millimeters (mm)

Can it still be used if the O-ring contact surface is scratched?
No — if the O-ring contact surface is scratched, the seal may be compromised, increasing the risk of leakage. In this case, the component should not be used.

Are the flanges compatible with Blu-Sub aluminum and acrylic tubes?
Yes, the flanges are compatible with both aluminum and acrylic tubes of the same size and can be interchanged directly.

Should O-rings be greased every time they are used?
Yes, applying lubricating grease to the O-rings is highly recommended. It helps remove dust and particles during application, keeps the O-ring in place within the groove for easier assembly, and allows for smoother insertion into the tube. Failure to apply grease can make insertion difficult and may lead to deformation or damage of the O-rings.

What is the purpose of the notch on the step?
The notch is designed to accommodate a tool, making it easier to disassemble and remove the flange.

What are the side threaded holes used for?
These holes align with the side threads on the aluminum tube flanges and provide additional mechanical retention. For acrylic tubes, they are generally not necessary — instead, a slight internal vacuum (using vacuum accessories) can help prevent the flange from coming loose. Alternatively, securely tightening the end caps is typically sufficient, as internal air pressure helps keep the flange in place. The side screws serve as an extra layer of protection, primarily for aluminum tubes.

What should I do if the screw threads become stripped?
If the threads are stripped, the flange should be replaced immediately. Continued use may compromise the seal or mechanical integrity. To prevent this, avoid over-tightening in future assemblies.

Why can’t the flange be inserted without O-rings?
Without O-rings, the flange may tilt during insertion, potentially scratching the inner wall of the tube. This can damage the sealing surface and compromise the watertight integrity.

What screw length should be used to install end caps?
Choose a screw length that allows for secure fastening without bottoming out in the threaded hole. Avoid over-inserting the screw to prevent damage to the threads.

3D Model Viewer

Note: The 3D model shown above is for reference purposes only. It may include components, accessories, or alternate sizes not included with the product. For simplicity, only a single representative size is typically displayed when multiple versions exist. Please refer to the product Shipping Guide for detailed information on included contents and size-specific differences.

Download 3D Model (STEP) - 85mm Flange

Download 3D Model (STEP) - 115mm Flange

Download 3D Model (STEP) - 165mm Flange