Peter Chan

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since Sep 11, 2017
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Recent posts by Peter Chan

Glenn Herbert wrote:The stove the women are making is not a rocket, but the techniques are applicable.

I have built a rocket bake oven and a rocket stove of cob. The oven has a cob L-tube with about 6" diameter, 2'+ horizontal and 30" vertical splitting into several channels under the (firebrick) oven floor and entering the oven at the edges, then leaving through a chimney. It takes some time to heat up, but bakes well. By the charring on the wood door, it gets to at least 400F inside.

The stove is all cob, formed around a sacrificial scrap wood inner 6" J-tube form, with a 1/8" steel cooktop, and a 6" stovepipe chimney leaving the space under the cooktop. It seems to work well in early trials after adjusting the gap between the riser and cooktop. 4" was too much, 2" or so is better. The riser is about 34" tall from burn tunnel floor, and could be shorter and would probably heat the cooktop better.

The inner form set in place on the base:

Burning out the form after applying the first layer of cob:

The finished stove:

The photobucket images don't want to show up apparently...

Glenn, this is AMAZING!   I had friends who were potters and made their own kiln every couple years, but I never had the opportunity to watch them build it or see it in action.  

Would you be willing to give an update on this cob cooktop RMH you built, such as how has it held up, is it still effective, etc. ?  Did you use different cob mixes for different parts of it or all the same stuff?

Also, do you hav pictures of the oven and would you give an update on that as well?

Again, this is awesome!!!  Ever since I spent a day at a farm in Wisconsin and toured the cob home of the farmer who built it all with clay from his land, mixed with a pitchfork on a plywood board, i've been fascinated by what can be done with just cob. 
3 hours ago
i just bought the Wisner book, and I'm hoping they cover how long a barrel over the riser will last, and how long other materials can be expected to last!!
19 hours ago
thanks :)  i don't know of anything Peter and Donkey have for sale, but i bought The Wisner book!
so the left side of the structure is closed off a bit so that the path is only as wide as the end of the "U"?
Glenn, thanks.  I guess that's where the art (or maybe the science?) comes know how to build all of the components correctly so that you don't need that extra boost.  i'm guessing those components include
-having the right air intake, primary and/or secondary
-having the riser tall enough
-having a manifold of the right size in relation to other part sizes

it seems like there are formulas for all this with the J tubes, but I haven't yet read Erica and Ernie's book.  i wonder if all the formulas stay true when one is using a stratification chamber/bell(s) instead of a flu system.  i also wonder if the formulas ring true when building batch boxes.  There appears to be so much innovation going on between Peter and others with the batch boxes right now....very exciting!!  Sometimes when I think about what Peter and others have just blows my mind, as I can't even fathom the smarts required.  My goal is to make it to Wheaton's place or an ATC someday and finally get some hands on experience with building a RMH.

Satamax Antone wrote:The barrel is just a radiator.

If somebody can show me a rocket, with a barrel on top, as an outside test. With no chimney, flue or anything but the barrel on top of the heat riser, and a gap at the bottom of the barrel, to let the gases out. And this setup works without smoking or works as well as the same rocket without barrel. I want to see.

Except in a few and far between cases, where there is no chimney. And in these cases, the heat riser acts as a chimney anyway.  A chimney is needed to run a Rocket. There is no sucking from the barrel.

Matt, you have heard that this is the case. But, it's all gibberish. Try the test i mention above. If the barrel was beneficial to the draft, a J tube rocket; feed tube, burn tunnel; and heat riser. Well made and properly insulated; would run better when we put a barrel over it.  It's not!

Again, people will disagree. Guys, do the test.

If you want no barrel, it's perfectly possible.

Look at this one


How strange! No barrel? How can it work?  And it's a J tube, not a Batch.

Hi, I thought the chimney needed to be next to the combustion chamber in order to heat up and create more thermal the video, his chimney is on the other side of the wall!! ?
2 days ago
Thanks so much for sharing this.  It is really interesting!  I can't tell from any of the diagrams or pictures what the other side of the thing looks like (the space between the end of the "U" and the manifold).  would love an explanation or diagram so I can understand this part.  I've never built anything, but I've followed your tech for several years on donkey's boards.  After doing this for several years, I finally feel like I'm starting to get the concepts and some the terminology.  I think all of you are so wonderful and creative and inspiring.

paul wheaton wrote:Set it up for $1 and then set it so that it is no more than $1 per month. 

thanks, i did that!  is there a place to donate to Peter and Donkey and Uncle Mud and Erica?  p.s. does anyone besides Erica and Ernie provide design and build services?

paul wheaton wrote:I just added this to the first post:

For $1 you get:

  • Care and Feeding of a Rocket Mass Heater (30 minute video)
  • Early access to podcasts (one week lead time)
  • Early access to videos (one week lead time)
  • 11 podcast review of "Botany in a Day"
  • 10 podcast review of "Just Enough"
  • Podcasts 1-120 in convenient zip files
  • ability to make content suggestions

I'm open to suggestions on how to manage my patreon page.  I am still quite new to it.

The video is out there now.  The other stuff should be out there tomorrow.

Paul, pardon me if I don't understand the Patreon, but, is there an option for one-time gives?  I am afraid that if I select the video patron, you might put out 1000 videos, and it will cost me 1,000 smackeroonies.  its not that i don't want to give you 1,000 smackeroonies, but i need to know what i'm giving, and when.

Thanks for the help and I'd like to make sure I send some every year, in addition to the awesome purchase of the woodstove DVDs.
[quote=Kirk Mobert

I think that because my mix is really light (wood ash and all) it insulates well, which helps get the temps up. The other important detail is undersized bell leading to a hot chimney (not too hot, you'd have to work hard to get burned on it).

....The firebox mix is intended to be able to make anyplace in the world, by the poorest people.

thank you for sharing the wonderful pictures and details!  When you say the mix was really light (wood ash and all)...are you talking about just the mix on the inside of the rise, correct?  is there any information on making and applying your own refractory mixes on these forums?
also, when you say the firebox mix is intended to be able to make anyplace in the world...what do you mean by 'firebox mix'?

thank you!

2 days ago