How to Light a Rocket Mass Heater




Introduction: How to Light a Rocket Mass Heater

It can be finicky at first, but with a little practice you can become a master at it!

Explaining what the heck a rocket mass heater is would be outside the scope of this instructable, so it assumes that you already know what one is.

This particular one is a very long system. Forty foot horizontal with two 90 degree turns and a 12 foot chimney.

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Step 1: Fire Muffins!

These are essential to get the fire started.

Mr Tidwell makes his with wax and sawdust, and sometimes tallow and sawdust.

I use two, just to be sure. : )

Place at the base of shaft, slightly forward towards the exhaust tunnel.

Propane torch is the easiest option as the bottom of the shaft is about 18" below. You could light them by hand and place them in... but that sounds like an opportunity for ouchiness.

After they are engulfed in flames for a few minutes you are ready to put your kindling sticks in.

Step 2: Fill 'er Up With Kindling

Arrange sticks in a criss-cross manner, bottoms resting over the alight muffins. Careful not to crowd the space. You want room to get the poker in there to jiggle things around for better air flow.

Use the driest of sticks that you have, with lengths of a few inches shorter than the shaft.

This particular system is slightly ghetto and has a few cracks in it, so sometimes it needs a little help from the fan to encourage the whole downward/horizontal draft thing. Otherwise you end up with a smoke-filled shop. Not good!!

Every five minutes or so you want to check on the sticks. Give them taps with a poker or forge pole, to get them to collapse the amount they have burned. Use the poker to move the bottoms a bit, essentially stirring them up, lifting the newly-formed ashes to get some more air down there.

You want intense flames to burn the initial kindling quickly. The goal is to create a bed of hot coals.

Step 3: Get the Pump Going

At this point you need to babysit it. Watch the quick video. It's really cool and explains a bit about what's going on.

Step 4: Don't Go to the Grocery Store

Well, maybe if it is just 11.5 minutes up the street and you don't have too much to get. Breathe hard and walk quickly; all the meandering Sunday shoppers will get out of your way. If the cashier or person behind you gives you a look for having 13 items in the 11 item express lane, tell 'em you got a pregnant sister in the car. Works every time.

Step 5: It's a Miracle!

You made it back in under 30 minutes, and you're left with a beautiful bed of hot coals and 3" left of a stick, Woo hoo!

At this point just stir it up, add enough logs to mostly fill it up, and you can now walk away for about 45 minutes, no more than 50 or you are really risking it.

That's it, you're done!

Hopefully this helps if you are ever stuck in a strange, cold place with an ugly barrel contraption that supposedly is the most efficient heating system ever designed by a bunch of hippies permies.

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    2 Discussions


    5 years ago on Introduction

    All rocket mass heaters are "slightly ghetto". That's why they are so unique and useful! Good instructable. I'll have to try your techniques in my shop!