A jack of all trades is a master of none, but oftentimes better than a master of one.
— Often attributed to William Shakespeare, though its true origin is debated. The earliest known form of the phrase dates to the early 1600s.
You Don’t Need To Be an Expert — You Need To Be Curious
Building a rebreather is a bit like being a one-person pit crew. You won’t need a degree in any single subject, but you will need a working familiarity with a surprisingly broad range of skills — some mechanical, some scientific, some practical, and one that’s really just about disciplined thinking.
The phrase above is often shortened to “jack of all trades, master of none” — which makes it sound like knowing a little about a lot of things is a weakness. But the full version says the opposite. History’s greatest polymaths — Leonardo da Vinci, Benjamin Franklin, Isambard Kingdom Brunel — achieved what they did precisely because they could draw on knowledge from many different fields. When you understand a bit of materials science, a bit of fluid dynamics, a bit of machining, and a bit of risk analysis, you start to see how all the pieces of a rebreather fit together in ways that a narrow specialist might miss.
That’s the spirit of this section. We’re not going to make you an expert machinist, a qualified metallurgist, or a professional engineer. Instead, we’ll give you just enough understanding of each topic to make informed decisions, ask the right questions, and know when something needs more attention. Think of it as a toolkit for your brain — one tool for each type of problem you’ll encounter along the way.
What This Section Covers
Below are the eleven topics we’ll work through. Each one is a self-contained guide that covers just enough to get you confident with the subject. You can work through them in order, or dip into whichever topic is most relevant to where you are in your build.
- 1.1
What CAD is, how the rebreathology CAD library works, and how to view and use CAD files for your build.
Guide - 1.2
How to read a technical drawing — dimensions, views, annotations, and what all those lines actually mean.
GuideInfographic - 1.3
Why “close enough” isn’t always good enough — understanding fits, clearances, and when precision matters.
Guide - 1.4
Metals, plastics, and composites — what works underwater, what corrodes, and what’s safe for breathing gas.
Guide - 1.5
Turning, milling, 3D printing, laser cutting — a plain-English guide to how parts get made.
Guide - 1.6
Services like Protolabs, Xometry, and Hubs — how to upload a CAD file and get parts made for you.
Guide - 1.7
BSP, NPT, metric — how threaded connections work, which standards to use, and how to seal them properly.
GuideInfographic - 1.8
How O-rings work, choosing the right size and material, and why lubrication matters more than you’d think.
Guide - 1.9
Where to buy standard fittings, valves, hoses, and hardware without manufacturing anything yourself.
Guide - 1.10
How gases and liquids behave under pressure and temperature changes — the physics behind your rebreather’s plumbing.
Guide - 1.11
Failure Mode, Effects and Criticality Analysis — the structured way to think about what can fail, what happens if it does, and what to do about it. Also known as Murphy’s Law, but with a spreadsheet.
GuideTemplate
How To Use This Section
You don’t need to memorise any of this. The goal is to read each topic once so that the concepts are familiar, and then come back to the relevant page whenever you need it during your build. Think of this section as a reference shelf — you’ll find yourself reaching for different guides at different stages of the project.
Some of these topics will feel immediately relevant (like O-rings and threads — you’ll encounter these on day one). Others, like FMECA, are more about building a mindset that stays with you throughout the entire design and build process. Either way, none of them require any prior experience. We start from scratch every time.