The Rocket Powered Oven: how to build your own super-efficient cooker

The Rocket Powered Oven

How to build your own super-efficient cooker

By Tim Barker

Illustrations by Joel Meadows

First published in 2016 by Very Edible Gardens PTY LTD (Australia). Second edition 2020.

Text © Tim Barker

Illustrations © Joel Meadows

This book is copyright. Apart from fair dealing for the purposes of private study, research, criticism or review, as permitted under the Copyright Act, no part may be reproduced by any process without written permission from the author. Enquiries should be addressed to the author. You can contact the publishers and both Tim and Joel via the form at www.appropriatetechnology.com.au.

Table of Contents

About this volume

Foreword: the future of fire

Introduction

Fire

Conventional stoves

Rocket stoves

The anatomy of a rocket stove

How a rocket stove works

Dimensions

Materials

Ingredients

Rocket stove power unit

Black oven

White oven

Building your rocket stove ‘power unit’

The mock up

Starting the stove

Final placement

The final build

Building a black oven

The baffle plate

Building a white oven

Barrel safety

How the white oven works

Making the inner barrel

Making the outer barrel

Closing up the outer barrel

The shelves

The door

Building the door latch

The stand

Insulating and covering the oven

Final touches

Controlling the beast, or how to cook with your oven

Taking care of your beast

Tips and tricks

Learn more!

VEG appropriate technology workshops

About this volume

In this booklet Tim and Joel take you through a step-by-step guide to building an extremely cheap, rocket stove powered oven using easy to access materials such as bricks, clay and reclaimed steel barrels. These designs may not quite have the domed top elegance that has made the backyard cob pizza oven so trendy, but they do have a farm yard charm of their own. And rather than taking hours to heat up to cook a couple of pizzas (and subsequently only used once a year!), these are super efficient, and very practical stoves. Both Tim and Joel use theirs on a daily basis. Their potential as a genuinely sustainable backyard fixture of the future is very high.

In the first section you’ll learn about the fascinating principles of the rocket stove, and in subsequent sections they will get down to the detailed business of building them. To complete the projects yourself, you’ll need a handful of common tools, and a little confidence using them, but the process will demand nothing beyond the scope of the most casual backyard tinkerer. The focus of this volume is on cooking, and we’ll be presenting two options for DIY ovens, appropriate for both outdoor and – if correctly flued and sited – indoor use. The foundational section on the rocket stove base, will also serve you well for other rocket stove applications, namely hot water systems and home heating – two topics we’re hoping to cover in complementary booklets in the not too distant future. Stay tuned for these (and upcoming workshops) at: www.appropriatetechnology.com.au

Foreword: the future of fire

Adam Grubb

Around a million years ago our ancestors learned to control fire. So significant was this moment, that by the time we evolved into Homo sapiens some 350,000 years ago, our whole digestive system had come to expect its food cooked, and our lungs had adaptations to cope with air pollution.

It’s somewhat humbling therefore to learn that for those last one million years – and let’s be frank here – we’ve been doing it wrong.

Three billion people continue to cook on biomass each day. The smoke caused by this (despite our genetic adaptations) is a major health issue, and the excessive use of fuel is a major environmental one. Smoke however, is nothing but unburnt fuel, and more efficient combustion offers both more heat, and an end to the cancer and coughing.

Enter the rocket stove. First conceived by Dr. Larry Winiarski in 1982, the rocket stove is so subtly simple a technology that it could have been around for all one million of those smoky years. Talk about missed opportunity. But at least it is known now. In retrospect it’s an almost obvious concept: burn the fuel first and fully, and then, and only after complete combustion, extract the heat. At the crudest end of the spectrum, you can build them with nothing more than a few bricks and some mud. It’s perhaps this simplicity – it’s not a Tesla sports car after all – that explains why the Wikipedia ‘rocket stoves’ entry at the time of writing sits at a measly 150 words. But trust us, this may be a much more revolutionary technology than any over-hyped sports car.

No one I’ve met has as much enthusiasm, knowledge, and hands on experience in rocket stoves as Tim Barker. Tim is a perennially ash and grease-stained appropriate technology tinkerer with a professional mechanic background, combined with years of experience in permaculture. He also admits to having something of a pyromaniac tendency. He probably would have made a fine supervillain but thankfully he’s harnessing his powers for good. You’re helping keep him on the narrow path by downloading this booklet. Seriously, with a dearth of good, cheap, accessible information about rocket stoves, a better person could not be found to produce this booklet. Our illustrator, Joel Meadows, is a himself an appropriate technologist, craftsperson, metal worker and permaculture practitioner par excellence. When Tim and Joel get together the ideas flow and sparks always soon fly. Figuratively and literally. They are always pushing themselves, always learning, and we’re extremely proud to have them together in this much needed publication that can help you avoid the pitfalls, and make a great rocket stove powered oven to call your own.

Adam Grubb is Co-director (with Dan Palmer) of Very Edible Gardens PTY LTD in Melbourne, Australia, and co-author of The Weed Forager's Handbook and The Art of Frugal Hedonism.

Introduction

For a long time I’ve thought that more information was needed for the construction of rocket stoves that could be used on a day to day basis. Typically, most people constructing rocket stoves have done so using materials and methods that practically guarantee they will either fall apart or simply become novelty items in a very short time. While it is certainly important to experiment (vital, even) once you have reached a good