First build

Hi everyone, new to the site and to RMH. I have watched and read about everything thatvthere is on RMH, i just mocked up the core out of full fire brick and tested it several times. That works great. I have a 55 gal drum to put over that and so my next question is this: what is the best method of putting that on and then how do you put on the exhaust out of the bottom? More info: i have the lid and lid clamp for the barrel, was thinking i could use them on bottom, cutting the lid to fit the fire brick riser, and then mount than and the retainer to the core, thereby allowing easy access to the riser for cleaning etc....all input appreciated!!! Thanks

Hi Scott;  
Welcome to Permies!  And welcome on your journey to becoming a rocket scientist! Now that you have the bug you won't be able to go back!

Lets start by asking if you own a copy of the "Buiders guide" written by Ernie & Erica Wisner. Readily available on Amazon or from them directly.   This is the go to book for all new builders and accomplished builders.
The Wisners  have over a 1000 rmh builds across the country. This book is worth every penny!

Ok, you built up a firebrick core, and it works great. Now you want to add your barrel.   A barrel with a removable lid should always have that lid on top. You need to see how your riser is working and how much ash might be building up.  Putting on the barrel with the lid down is not a good idea, you would need to lift it off every time to see anything. Your barrel should have the bottom cut out leaving the lid to be on top.
When you add the barrel to a RMH you are creating the start of your "horizontal transition area"  This area MUST be large enough!!! I can't stress that enough! Many new builds do not perform as expected by this area being to tight.  Bigger is better!
There are a couple of ways to start the "horizontal transition area"  I prefer using a brick box myself. With a brick box 2/3 of your barrel should sit on top of your core leaving apx 1/3 hanging off the back, over your new brick box. That box should have an ash cleanout door, should also have a lower ash collection area, and finally that is where your horizontal pipes will start.

Some folks prefer to use a 55 gal barrel to transition , similar to what you were thinking. Only you need 2 barrels . One like you have with removable lid and the bottom removed and another that is cut down to fit around your core leaving the top to be connected to the full size barrel with a second clamp. This method works well as long as it has a large enough exit to not stall the hot gasses.


I assume your mock up is out side. Be prepared that when you put the barrel on your mock up it will effect performance.  To truly perform correctly a rmh needs its warm mass to help direct the exhaust thru and up the chimney.  Mock up building is for you to test designs and gain confidence with your building skills.

I strongly recommend you get a copy  of the builders guide it will help you more than anything!

First, thank you Sir for your great info! I have not yet gotten a copy of the book but will be ordering it asap! So the second barrel is just to create the transition from main barrel to the mass is this correct?

Yes , A second barrel or a brick box is to have an area for the fly ash to settle and for the hot gasses to "transition" to a horizontal flow.  Any size restriction in this area will badly effect how well your rmh works!

Ok great, thank you Sir!