How This Site Is Organised

Yes. Yes, you can. Part I is where everyone starts — whether you’re a curious diver who’s never picked up a spanner or an engineer who just wants to know what makes rebreathers tick. We’ll walk you through the ten practical skills worth having before you begin (none of them require a degree), give you a plain-English tour of what’s actually inside a rebreather, and help you figure out which type suits the diving you want to do.

This is also where we cover the science — but only the science you actually need. Just enough physics and chemistry to understand what’s happening when you breathe on a loop, without anyone reaching for a textbook. Think of it as pub-level gas physics: if you can understand why a balloon gets smaller when you take it underwater, you’re already halfway there.

• Section 1: 10 Things You Need to Know
• Section 2: What’s in a Rebreather, Anyway?
• Section 3: What Type of Rebreather Should I Build?
• Section 4: The Science You Actually Need

Before you start bolting things together, it helps to understand what each piece does and why it matters. Part II takes you on a deep dive into every major component in your rebreather — the scrubber that removes CO&sub2;, the counterlungs that act as your breathing reservoir, the mouthpiece and hoses, the gas supply system, and the housing that holds it all together.

For each component, we explain what it is, how it works, what your design choices are, and what to watch out for. By the time you’ve finished this part, you’ll be able to look at any rebreather and understand exactly what every piece is doing — and more importantly, why.

• Section 5: The Scrubber — Your CO&sub2; Removal System
• Section 6: Counterlungs — The System’s Breathing Bags
• Section 7: The Mouthpiece, Hoses, and Breathing Loop
• Section 8: Gas Supply — Cylinders, Regulators, and Valves
• Section 9: The Housing — Cases, Backplates, and Harnesses

This is where the real fun starts. Part III is structured around a simple idea: every rebreather shares the same foundation, and what makes them different is how fresh gas gets added to the loop.

So you’ll start by building the foundation — the scrubber, breathing loop, counterlungs, and housing that are common to all types. Once that’s done, you choose your gas addition method: constant mass flow orifice, bellows-driven addition, or electronic solenoid control. Each method is a self-contained module you bolt onto your foundation, and each one gives you a different type of rebreather — from a simple pure-oxygen unit all the way up to a fully electronic closed-circuit system.

We also cover the sensing and monitoring layer — O&sub2; cells, CO&sub2; monitors, displays, and controller integration — because knowing what your gas mix is doing is just as important as controlling it.

• Section 10: The Foundation — Building Your Scrubber and Breathing Loop
• Section 11: Adding Oxygen and Other Gases
• Section 12: Sensing and Sensors — O&sub2; and CO&sub2; Monitoring

Not everyone needs Part IV, and that’s absolutely fine. But once you’ve built a working rebreather and got a few dives under your belt, you might start wondering about sensor voting logic, DIY Arduino controllers, data logging, or building proper redundancy into your system. This is where you’ll find all of that.

We also cover the serious topic of bailout planning and emergency procedures — what to do when things go wrong, because eventually, something will. It’s not dramatic; it’s just good engineering practice. And we finish with testing, validation, and maintenance: how to prove your build is safe, and how to keep it that way.

• Section 13: Advanced Electronics and Controllers
• Section 14: Bailout and Redundancy
• Section 15: Testing, Validation, and Maintenance

A quick-reference section in the grand tradition of the “For Dummies” series. Five short sections, each built around a list of ten. You’ll find ten reasons to build your own rebreather, ten safety rules that could save your life, ten common mistakes and how to dodge them, ten essential tools for your workbench, and ten ways to improve a rebreather you’ve already built. They’re designed to be dipped into whenever you need a bit of practical wisdom or a confidence boost.

• Section 16: Ten Reasons to Build Your Own Rebreather
• Section 17: Ten Safety Rules That Could Save Your Life
• Section 18: Ten Common Mistakes and How to Avoid Them
• Section 19: Ten Essential Tools for Rebreather Building
• Section 20: Ten Ways to Improve Your Existing Rebreather

The back of the book, if this were a book. Part VI is your reference library — a glossary of every rebreather term used on the site (in plain English, naturally), gas calculation cheat sheets with worked examples, the scrubber performance database, a supplier and resource directory, further reading for the truly curious, and printable pre-dive checklists for every rebreather type. Bookmark it. You’ll be back.

• Appendix A: Glossary of Rebreather Terms
• Appendix B: Gas Calculations Quick Reference
• Appendix C: The Scrubber Database
• Appendix D: Supplier and Resource Directory
• Appendix E: Further Reading and Research
• Appendix F: Pre-Dive Checklists