End Cap
Retaining Ring
Secure Seal
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In stock
Waterproof PMMA Tube for Pressure Cabin - 5mm Wall, 60-160mm OD
$12.99 USD
Customization Service
We are the OEM ODM manufacturer. For bulk orders and custom solutions, please contact us at official@hobbywater.com
When will I get my order?
We prioritize fast order processing. For in-stock items, orders placed before 4:00 PM (Beijing Time) will be shipped the same day. Standard orders typically ship within one week, while customized orders require approximately 15-30 business days for production and delivery. Delivery times may vary under special circumstances.
Shipping Methods
We ship to most countries worldwide. However, please ensure compliance with your local import regulations.
- For the USA: We offer tax-inclusive shipping options. Expedited orders are shipped via DHL, UPS, or FedEx. Note: DHL does not allow undervaluation.
- For other countries: Tax-inclusive shipping is available upon request. Otherwise, orders will be shipped via 4PX by default.
For specific shipping requirements, please contact us in advance.
Waterproof PMMA Tube / Pipe – for Pressure Cabin Components
Professional Acrylic Tubing for Underwater Applications
This acrylic tube is specifically designed for pressure cabin and submersible housing applications. Manufactured with professional cutting technology and finished with annealing and stress testing, it delivers clean, flat cuts and reliable performance under pressure.
Note: The picture shows the acrylic tube only, not a complete kit.
Key Features
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🔬 Professional Annealing Process – Reduces internal stress, prevents cracking and deformation
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✂️ Clean & Flat Cut – Precision cutting technology leaves no residual debris
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💧 Underwater Pressure Ready – Stress-tested for improved sealing performance
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🛡️ High-Quality PMMA – Transparent, durable, and waterproof acrylic material
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📏 Multiple Size Options – Various outer diameters and lengths available
Specifications
| Parameter | Details |
|---|---|
| Material | PMMA (Acrylic) |
| Wall Thickness | 5mm |
| Outer Diameter Options | 60mm / 90mm / 110mm / 130mm / 160mm |
| Length Options | 200mm / 250mm / 300mm / 400mm / 500mm |
| Process | Annealed + Stress Tested |
| Application | Underwater pressure cabins, submersible housings |
Why Choose This PMMA Tube?
✅ Stress-Relieved – Annealing process ensures dimensional stability
✅ Tested for Reliability – Stress-tested before delivery
✅ Ready to Use – Clean, flat cuts with no additional finishing required
✅ Customizable Options – Choose from multiple diameters and lengths
Package Includes
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1 × PMMA Tube (selected size: __ mm OD × __ mm length)
What are the different part configurations for the chamber assembly, and do they need grease?
Option 1 – One dome + one end cap (assembled):
- 1x Hemisphere dome, 1x Chamber tube, 1x Flange, 1x End cap, 1x End cap retaining ring
Option 2 – One dome + one end cap (all separate parts):
- 1x Single dome, 2x Flanges, 2x End cap retaining rings, 1x Chamber tube, 1x End cap
Both Option 1 and Option 2 require 1x Dow Corning grease.
Option 3 – Two end caps:
- 1x Chamber tube, 2x Flanges, 2x End caps, 2x End cap retaining rings
Option 3 does NOT need grease.
Why does the flange pop out when I try to close the cabin?
If the flange springs back while you try to close the chamber, the chamber is almost certainly sealed at the other end. The fix is not force — it is assembly order.
Root cause
When one end is already fully sealed, the air trapped inside has nowhere to go. Closing the opposite flange compresses that air — and the pressure pushes the flange straight back out.
Correct assembly sequence
- Install the dome on one end Start with a single hemisphere. Leave the opposite end open for now.
- Fit the flange on the open end — without the retaining ring At this stage the chamber can still breathe. Air escapes through the gap as you work.
- Seat the flange fully With the air able to escape, the flange slides into place instead of being pushed back.
- Install the end cap Only once the flange is fully seated.
- Install the retaining ring last The ring is the final step — it locks everything in place after the air has been released.
Key rule
Never fully seal the back end before the front is closed. Keep the retaining ring for last — the chamber stays vented, the air escapes, and the flange stays put.
Lubrication
Yes — apply a suitable grease (e.g. Dow Corning lubricant) to the O-rings and sealing surfaces. Parts slide into position more easily and the seal performs better.
Still won't close?
Contact us with a video showing the full assembly process, both ends included. We'll review it with the factory and help you resolve it.
Sealed Chamber · Installation SOP
Image unavailable. Please follow the text steps below.
1. Chamfer the Inner Edge
FILE
Use a file to grind a 1–2 mm chamfer on the inner circumference of the acrylic tube.
Purpose: Enables smooth flange insertion and prevents damage to the sealing ring.
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Use a fine-tooth file. Apply even pressure to achieve a smooth, burr-free surface.
2. Apply Lubricant
LUBRICATE
Evenly coat the entire sealing ring with sealing ring lubricant.
Purpose: Ensure full coverage and remove all dust or particles to maintain seal integrity.
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Clean the sealing ring with a lint-free cloth before application. Apply a thin, even layer only.
3. Install Cover & Pressure Plate
ASSEMBLE
Place the sealing ring, then put on the chamber cover. Install the pressure plate on top.
Purpose: Ensures optimal sealing and extends the service life of the cover.
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Tighten pressure plate screws in a diagonal pattern to distribute pressure evenly.
4. Secure Feed-Through Screws
FASTEN
Screw in the feed-through screws. Thread-locking adhesive is recommended to prevent loosening.
Purpose: Prevents screws from loosening due to vibration or long-term use.
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Use medium-strength thread locker (e.g., Loctite 243). Apply to 2–3 threads per screw.
5. Press Fit the Sealing Ring
FINAL
Fit the sealing ring and press it evenly into the acrylic tube until fully seated.
Purpose: Ensures the sealing ring is fully seated, creating a reliable seal.
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Use a pressing tool or a soft-faced mallet if needed. Never use metal tools directly on the tube wall.
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Final Installation Checklist
- Sealing ring seated evenly with no twisting
- Lubricant applied uniformly, free of particles
- Cover and pressure plate secured without play
- Feed-through screws treated with thread locker
- Sealing ring fully pressed into acrylic tube
