Rocket Mass Heater for my home

[matt walker]

As it turns out, poking around in my shop I found a marine diesel heater with a little hinged door/window! I just fabbed up a little trim ring for it, and cobbed it in! Done and done. It's smaller than what I would choose, but free and here are both good things.

[matt walker]

Like so....

[pa_friendly_guy]

WOW, Looks Great Matt, and it was free, and it was handy, and it works well. Hold your cards everyone, We have a BINGO here. Hold your cards there is a BINGO. I think it works perfectly for what you wanted. I like the large stone you placed in front. Do you plan on putting in some more stone work in the front as you finish the cobb work? It looks good and putting in a few well placed stones will add to the effect. You don't have to stone the wings and benches if you don't want to, but the front with your new door would look nice stoned up. Just my opinion, it is after all your home and you have to like what it looks like. So far I think it is turning out Great. Seems that every day you are making progress. I have been enjoying the pics. Keep up the good work.

[matt walker]

Thanks for the encouragement Guy, I appreciate it. I'm definitely going to be adding more rockwork. Not sure how much yet, but I too really like it. The bench I have in is around 4" shy in all dimensions right now to allow some wiggle room for the final finish. I'm still sketching it out in my head as I sit around the fire and think about how I want it to be. We'll see.

[pa_friendly_guy]

Hey Matt, It has been awhile since we had a progress report. We got a cold snap here in the North East, wind chills of -5 below. I didn't know if it was too cold to mix any more cobb, or if you over did it and your back hurts and you decided to take a few days break. Or if you were far enough along to see how well it was going to work and you just decided to stop working and enjoy the heat for awhile. Any of those options is OK with the group, or at least ok with me, I shouldn't speak for the group. Just wondered how the project was progressing. All of my out door projects have come to a grinding halt. I was hopeing to live vicariously through your progress. Let us know how things are going.

[Lollykoko]

I had a visitor Saturday evening, when Adoptason delivered my broken heater. This is the one that was in use when the power outage hit a couple of months ago. The company received my documentation and sent shipping labels to have it bundled off to a repair shop.

Since I knew he was coming by, I had this thread queued up to flip though, showing photos of your progress, Matt. He is my "strong back close to home" and frequently gets roped in on my projects. He'll start to worry when I make a trip to the masonry store.

[matt walker]

Glad to hear you guys are paying attention! I've been off the computer for the most part for the last three days while I dug, mixed, and schlepped more cob! I've got some more progress to report, but am going to have a busy week with real work this week as well. I'll try to get some more pictures up, but let it be known that last night I made my first complete meal on the stove, including a little loaf of bread baked in the oven, and stew simmering on the lower cooking surface. I've got some innovations to share.

[Lollykoko]

Goodie, goodie! I'm excited for you and waiting to hear more.

[matt walker]

Okay, so I left off with figuring out the door/window on Wednesday. I got back to the build Friday. First thing was to muck up the other bench, so I started with digging and hauling and cob dancing. Then I worked on layout and made sure I had everything in place.

This photo shows the smaller vent tubes that will allow air flow behind the brick wall. The brick wall has intake slots along the bottom and larger exit openings along the top, so once it heats up it pulls cold air off of the floor and warms it before pushing it out at the top. I decided to make a couple larger voids for storing wood and a poker and maybe warming my slippers while I'm at work, so I used some extra stove pipe to form molds for those "caves."



Then, I brought in my mud. I did okay, but it got a little deep towards the end and I had some sagging. Not to worry though, I knew I couldn't do it in one application, so I let it go. One thing I'm learning about this medium is you can get kinda loose and wild, and go back and hack it up and try something else. I'm loving the cob. So, here's my east bench after the first application.



That was all done on Friday, and on Saturday a couple curious friends wanted to experience the cob process, so I patiently showed them where the clay was and allowed them to do the digging, hauling, and mixing. Aren't I generous? I was really thankful for their enthusiasm, as I was getting kinda sore! We did a final shape on the west bench, and screened some clay to try to make a plaster for finishing it. It was fun playing with the different mixes, and I learned a lot. Here's the west bench after my helpers did their first cob work on it.

I made another arch mold with the bricks and some stove pipe, to make a void to set the clean out back from the face.

[matt walker]

Sunday, I mixed yet more cob, and got the east bench up to grade.



One great thing about having the help on Saturday, is I was free to experiment a bit. I found an old cast iron pan and stuck it in the clay above the viewing tunnel.



So, Sunday night, after finishing up the east bench, I made a little tiny sourdough ball, and stuck it in my newly discovered Rocket Mass Heater Oven!



I set my stew to heat up on the top of the barrel, and once it was hot put it on the warming plate there and it stayed just shy of a simmer while the bread baked below it. Perfect.


That was the best meal I've had in a long time. I'm so excited about the oven, I think eventually I will chip it out to be a larger area in there, it just works great. I can regulate temperature by covering or uncovering the feed tube, or by adjusting ventilation through the door. My bread was amazing.