Golden Aldi's planning thread

[GoldenAldi]

Hi Matt,

I absolutely LOVE your rocketstoves... and I love the fact that you share all of your knowledge with others, through pictures and videos. You've inspired me to want to build a few for myself now, but the one for the house will have to wait, due to strict fire regulations here in Germany, but the first one for the patio has been started, no codes yet for having one outside! Hurray!

I used these rock blocks, not sure what they are called in english but translated, they would be called "chimney blocks", its where the inner core of the chimney would go through, if you were building a conventional chimney. They are hollow, so I was wondering if I can use them for the mass. Does the size of the hot air ducts matter?

I used the measurements for the core taken from the book so the heatriser is 7x7 inches, same as the feed tube. Burn tunnel is half the size of the heatriser.

Unfortunately, I'm not able to find photos or a video, on how to connect, or how to make a nice exit from the bottom of the barrel to the part that will 1) flow into the mass, and 2)will have a clean out hole.
One has to understand, that things are much more regulated and controlled here. They more or less force you to buy new and expensive material and parts. I've seen the smaller stores close down, to make way for the huge DYI chains, and even there you won't be able to find certain objects, so you have to go to a special shop, and that's where it gets ridiculously expensive. I've seen cardboard, chicken-wire or even a sheet of thin metal to form connections, and then "cob" it in, and smooth it out. I figured that's how I was gonna have to proceed, and will probably need a t-shaped pipe that I will most likely have to buy, but maybe I could make it comepletely on my own, using y-tong stones... now as I type, this idea is coming to my head...

Please let me know, if the chimney blocks I'm using for the mass, if the tunnel would be too large, or if I should proceed differently for the mass... I hope I haven't confused you. I would appreciate any input...
Here are some fotos of what I've accomplished so far..... hmmm, how do I load them up here?

Aldi

[matt walker]

Hi Aldi, welcome. I hope you don't mind I split your post into a new thread so we could focus on your questions.

First, to post photos here you need to host them elsewhere and link to here. I use Photobucket. You can upload there, and then there will be an IMG link that you can paste here and the photo will show up here, it's really easy and allows you to load many more photos than we could handle here.

Size of the openings in the mass matters, but as long as the openings are significantly larger than system CSA it should work fine. System CSA is "cross sectional area", and is usually determined by the measurements of the burn passages in the core and riser.

Before you get any further, you said "burn tunnel is half of the riser", if you are referring to the 7"x7" measurement, than half is way too small. You want those to be the same, a little ash will always live in the tunnel so it will in practice be SLIGHTLY smaller than system CSA. That is a confusing passage in the book, and leads to a lot of headaches. It CAN be slightly smaller, but it's best to make it system size.

You have a good handle on how to form the joint from barrel to mass, using support materials to form the shape from cob. Once you start playing with cob you will answer a lot of your own questions. I strongly recommend you make a bucket or two of material and just play with it on an outdoor burner for an afternoon. It is a fun and very educational way to spend a few hours.

[GoldenAldi]

Hi Matt! And thanks for the welcome, so glad to have found you here! I don't mind at all, that you split my posting, on the contrary!

I've gone to Photobucket, and found my old account that I haven't used in yrs, so I've uploaded a few photos, now I'll try and load them here...



This was done according to the measurements given in Ianto Evans book.

I've gone back to studying the book, and have re-measured the dimensions. I don't have them in my head, as I'm always going back and forth between inches and centimeters, and numbers always get jumbled up in my brain, but I'll get the measurements down on paper tomorrow, after we go to the clay quarry---yipee!! I'm finally getting my clay!!

Anyway, I've decided to take the front apart, to see how the pull would be, and I have to say, that when I closed off the whole top, and opened up a brick on the bottom, and then lit a fire, the wood caught fire much quickly, and didn't go out like it did when I tried lighting it through the top. So I definitely want to change the front part to open and close, AND I want 2 windows... as I wanted to see the fire from the top... Also, lighting the fire from the bottom really sets off that rocket sound in no time at all, and I was able to see fire from above the stack, whereas I would only feel warmth feeding from the top.

Okay, now back to the burn tunnel length and riser height. According to the "book", it says on page 36 for the letter "D", which is the distance from the feed tube to the heat riser, that it should be as short as possible to minimize heat loss and to increase the barrel temperature. Optimum proportion is about half the height of the heat riser. Also says that longer tunnels will need more insulation, but I put some on anyway, am I over doing it? I think I'll stick with the insulation, even at half length. Insulation is good, and it will keep more heat in.

I'll be back tomorrow evening with more pictures... can't wait to start getting my hands all mucky!

[GoldenAldi]

Wow, pictures turned out a bit larger than expected... Anyway, I also wanted to post 3 more pictures focusing on the barrel exit and first clean-out, and one foto of where the exhaust pipe will need to be fitted to.

[mannytheseacow]

Welcome, GoldenAldi! I can't wait to see how that works out for you. I had a few of those chimney blocks laying around and was thinking how cool they would be for a bench, but I didn't have nearly enough to do it and didn't want to buy any. I bet they'll work well for you.

[GoldenAldi]

Hi Manny, and thanks for the welcome! I meant to answer you yesterday/last night, but hadn't gotten around to it! We had a lucky find with those chimney blocks, cause they came with the inside fire cylinders... about 11 of them. I figure I'd use them for some future rocketstoves. All for about $160 was a good deal/investment. I plan on getting alot of heat out of them one way or another

Today we drove to the clay quarry about over an hour's drive away. For about 10 Euros,($12), we shoveled roughly 300kgs of pure clay. Came out to about 8 wheelbarrels full. Feels really great!

I have two questions for today... one is, how exactly should I have the insulation around the heat riser... the way I already have it, or do I need to put more rockwool around the sides? I believe I've seen one wrapped similar to how I have it, but I'm not sure about its efficiency.

the other question pertains to the size of the exhaust exit pipe to go up and out... what size can I go with, considering the inner dimensions of the blocks are 11.5"x14", and the heat riser opening is 7"x7". I was able to acquire 10 pieces of pipe that are about a meter long, and 13cm in diameter, 5 1/8". Would that be too small for what I've built so far?

I measured the heat riser, and it has 35.6", my burn tunnel is/was exactly 17.8" on the nose... Again today, I lit a fire from the top, and it didn't fair that well. Again, I closed up the top fully, and opened up the bottom... seems like a much better pull of the flames into the heat riser, and you could hear the rocket sound as well as see the bottom of the riser light up, I mean, it was "lit" up by the light of the fire. I'm still not sure if I should have two places to place wood. Maybe when the chimney is cold, lighting and burning through the bottom first, then closing bottom and opening the top for stoking. I'm not quite sure... decisions, decisions...

One thing for sure, I want those windows! I just want to watch those flames. I think I'm a closet pyromaniac! My husband told he he doesn't like the smell of burning wood, I, on the other hand, grew up around campfires in the States, he most certainly did not. Oh well, he still thinks the rocketstove is cool, although he is very skeptical that it will function as well as those I have shown him through youtube vids. He's just not into it like I am, but he has been my driver and financer! He's also been cooking the past few weeks while I've been piddling around with my fire bricks, along with earning the dough to buy or get what I need to build it.

Oh, I just remembered another question I had. With the measurements taken from the book, my feed tube area was 4.5"x7"(width), does that seem to be accurate to what I should have? Even the ones I've been able to see seem to be much smaller. That's the thing when you don't get to see a rocket stove in real life.

[matt walker]

Ideally the feed should match the riser, as should the exhaust. You may get away with your smaller exhaust, I think it is worth a try. The smaller feed will work well, a larger one is almost always reduced to about that size with a partial cover of some sort. As for the insulation, you want as much as you can get on there while still having a good gap all around between insulation and barrel.

[GoldenAldi]

Hello Again! I've been pretty busy since I last posted, getting some clay from the quarry, gathering more materials, re-thinking and more planning... The weather hasn't been all that great either, windy, and very wet, but at least all the 200 liter rain barrels are full to the brim!

I was having a real headache trying to figure out how to connect the end of the barrel to the entrance of the stone flue. I just didn't have enough imagination, I suppose, since I'm pretty sure "we" would have figured it out. My husband is still very skeptical, the poor guy... see, post WW2 institutional schooling really does "dumb down" the young generations. Just a thought! I'm not very good in explaining it to him either, but he's been very helpful! Bless his heart, he was gone for 3 hrs, collecting some flues and elbows and ytong stones for dirt cheap, so I've scrapped the stone flues and now my headache is gone, no more elbow dilemma!

I've also found some thick glass, 1/4" thick, that we successfully cut ourselves, much to my husband's astonishment! He was sure it would not work! Now he's a believer, in this regard, anyway
I'll cob the inside part where the glass will be able to be slid into to close off the front. I love watching the fire rocket away inside. I've also played a bit with different recipes for the cob surrounding the whole core, and have decided to add a bit of rockwool and a handful of bits of straw. Its really been ages since I played in mud, but I believe I'm quickly getting very comfortable working and modeling with it.

Now here comes the question I need some feedback on... what kind of a shape should/could the space between the heatriser and inside barrel have? Most of what I have been able to actually "see", have been straight across the bottom, with just the opening in the space where the gases/air flow from barrel into the flue of the mass. As you can see on this picture, can I have it descending starting from the two sides? Or do I fill the whole bottom up with cob, and just leave a wide opening...

[mannytheseacow]

Right on! It's such a pleasure to see a new build!!!

I can't tell from the photo which way your exhaust is going to go... out the back? Either way, you'll want as much space as possible in there. Here's a link to the thread with my build that shows that area:


I made it a little too small at first and then went back and had to make it bigger. That seems to be a tricky area and the bigger you leave that space the happier you'll be.

Good luck!

[matt walker]

Cool! Like Manny said, make it as large as possible. Leaving those sides open the way they are will only help. That way the exhaust can drop and come at the transition from the sides as well, which is just what you want. Looks great so far!