Onto a new one.

Hi everybody.

Well, on my way to make a small six incher.


Start.


Castable vermiculite mix.


View from affar.


The jigsaw used to vibrate the vermiculite and casteable mixture.

Duh!

How do you embed a video here?

After seeing the video guys, how would you do the feed tube?

Weld a metal box, lined with refractory bricks? The small 3cm thick ones i'd say.

Nother thing, i can't realy have 5cm of insulation around the heat riser. Do you think i can get away with thiner?

Thanks a lot.

Max.

Well, i'll carry on talking to myself then



A little progress. I'm in desperate need of 3mm steel offcut to make the box welded to the bottle, to cast all thoses bricks in. The plan is to make a solid stove, which can be moved without breaking and which is smokeproof or airtight if you prefer.

Consider refractory "wool" blanket - Kaowool is one brand, there are many like it - for a "first world" highly-insulative but not very thick product. Ceramics/kiln supply places or refractory suppliers usually have it. It is VERY effective insulation. Not stunningly cheap, but there you go.

Hi L. Jones.

Thanks for the idea. You mean for the heat riser? Why not. Thought i was thinking castable/vermiculite mix for durability.

Well, you were concerned about reducing thickness of insulation, so using a more efficient/effective insulation would help to counteract any negative effect from that.

It's quite durable if not mechanically abused - it's used for portable raku kiln insulation and portable gas forge insulation. It would actually be most effective (but this would presumably mean changing your setup, as you've already started building) inside a metal pipe, with layer of "rigidizer" or "ITC" coating on the surface exposed to the fire - basically a thin cement-like coating that stays on the surface of the wool, locking the individual fibers in place and giving it a bit more durability in the flames (and supposedly reflecting more heat in the case of the "ITC" coatings), while the metal outside provides the mechanical support and protection from minor bumps and bangs (while not exposing the metal directly to the flames). It makes for a low-mass well-insulated high-temperature tube, which is (as I understand it) what you're after here - just that it's not really suited for the "low-tech" approach that drives a lot of the rocket stove development - but you're obviously not sticking to that, either, so it seemed reasonable to suggest.

Thanks again L. Jones.

Well i'll keep this in mind for a later build. I didn't think about coating kaowool. That's a good trick.

Thanks again.

Vaguely progressing.

Feed tube. I riveted a piece of stainless steel around the bricks, i used some thin 3cm ones, and broke one of the bottom of the feed tube, so only the sides are protected by firebricks. Tho, bottom is made of vermiculite, castabvle refractory mix. Tho, the sides are not insulated. I just used castable.



I wonder if i should make the heat riser temporary, for the moment to give it a try, or if i should cast it with vermiculite castable mix straight away?

Thanks.

Max.

Hi everybody.

Well, i did a temp heat riser, works lovely. No smokeback, and remember, it's a six incher with a four inch flue. Flue tube is at 66 degrees celcius at about three metres from the stove. I need to cool that down with Len's idea of adding a metal bell. I'm loosing a lot of heat to the outside. No good. I still think a cyclonic one would work better.

Len, it's done!

The tube is plunging deeper than the intake into the bell, but still bypasses. Tho, i'm extracting mo heat Within minutes the bottom of the bell was barely touchable. After an hour, the top half, xept the rounded end was still touchable.

Thanks for posting! May I ask a few quick questions?

The 'burn tunnel' is greatly reduced in length, it looks like the feed tube is almost right next to the heat riser....what are the costs and benefits of this compared to the longer burn tunnels in the book?

It looks as though only the bottom portion of the heat riser is insulated, with just metal pipe continuing above that, is that correct?

Does the exhaust pipe leaving the bell tank extend down inside the bell to below the level of the intake into the bell from the stove?

thanks! nice job...

Hi Kari. Heat riser is all insulated as is the feed tube, and burn chamber. The first gaz botle (reversed one) is replacing the barrel. I have about 2 inch gap. 153mm heat riser inside diameter, and 200mm outside. Insulated with vermiculite. Feed tube burn chamber is half firebricks with mixture of castable refractory mortar and vermiculite.

Yep, the exhaust tube is going down about 108cm inside the bottle, below the "intake" But still bypasses.