Figuring out length of tube / size of bell for a 6" system

[Bram]

Yeah so the ceramic top is really not so much of an option. We don't get ceramic glass here I believe. But I will try to get a cast iron top plate going. Do you think 15mm should be enough?

[Vortex]

Do you not have electric cookers with ceramic cooktops where you are? Most people seem to get the old ones from recycling centers to use. Cast iron is hard to get in thick sheets, and the thin stuff is prone to cracking. Can you not get hold of a top from an old cooking range, scrap yards often have them?

[Bram]

We get electric cookers here, but our stove is quite wide and I don't know how to cover all of it with just a single cooktop like that. I never truly understood how you did the one in your stove matthewwalker . How did you connect your stove to the chimney?

[Bram]

Alright I went back through the first video ever on the WRC and found the introduction to the top of the stove. It wasn't clear to me that the top directly above the stove was a ceramic glass stovetop like is used in electric cookers. Or if it was clear to me at some point I forgot.

And you really think that this is the best option? I guess that after the first pass of the fire through the top of the stove it loses a lot of its heat and you can use less heat resistant materials....

[Bram]

Okay I am answering my own questions here. But I went through the following video and found the piece where Matt starts to build the top. I am still wondering how I could best make this happen for my own build...

youtu.be/A8o7xvCP6Ik?t=1685

[matthewwalker]

Bram, I'm not clear on what you are questioning. Are you asking if I'm confident in this material? I am. I've used it for years now, it's a great choice for a wood fired cook top in my opinion.

If you can't span your whole top with one piece, create a countertop with stone or tile with a cut-out for the cook top. Insulate everywhere but the cooktop cutout with ceramic wool or board. In that way you can use less heat resistant materials for most of the top surface.

[patamos]

Ditto on the faith in ceramic glass tops. You'd have to whack one pretty hard with a heavy pot to crack it. Think of all the abuse those things take in the average home over many years. They have to pass some pretty stringent standards to be used in that major an application.
They also radiate less than equal thickness cast iron. But they conduct better.
The Ma n'Pa appliance centre in my town is happy that scavenge them from oven/stoves otherwise heading for the waste stream.

[Bram]

I guess I knew people were talking about ceramic glass but I never fully realized that it was recycled cooktops. And I understand now that you sectioned off your cooktop into the 'hottest area', where the cooktop sits and 'the rest' which can use other less heat resistant materials. And then cover all of that with a metal frame like in Matthew's original stove.

I will present the idea of using a stovetop and get back to you.

[patamos]

Hi Bram,

This heats 450 sq.ft dwelling in west coast Canada temperate rain forest. Easily on one batch, When below zero c one more reload will keep things warm for 12 + hours

vimeo.com/334174847?cjevent=e73b83aa9a1811e983ce012c0a1c0e0f

If you shape the outer shell of the fire chamber and down draft roughly 24 x 32 you can sit a stove glass top on it and have whatever core and side/downdraft chamber(s) you like.

To get to the far end of a bench i'd suggest a relatively fasts channel along the front (into the room), then a slower bell coming back towards the flue. This will help even the temps out.

Also, any major bend in the 90 degree range, good to widen the CSA by 50%...

With a bypass you can waaaay over size the ISA, but good also to have cleanout ports into which you can place bricks or w.h.y. on the floor or side walls to reduce the volume and speed things up.

[Bram]

Hi there everyone.

So it is proving exceedingly difficult to find a cast iron plate of that size so we might have to go for a regular steel plate of that size but much thicker. Also I have discussed using a recycled cooktop and my family doesn't trust it and doesn't like the aesthetic.

I have asked before about a regular steel plate and people said 15mm would be okay, is that still the opinion? It would get a frame of angle iron all the way around.

[martyn]

I have a plain 6mm steel plate on top of my rocket stove, it is made up of two pieces, am outer 30” ring with a 15” hole, the hole is covered over by a 18” circle of 6mm steel that is bolted on.
The reason for two pieces is to allow for movement without two much distortion, the outer plate become noticeably concave when up to temperature, the centre ring seems to stay flat.
The steel is heated to 300- 500c depending on circumstances and has seen around 200 hours of intermittent use.
The last time I looked there was quite noticeable deterioration but it looks good for a long time yet.

[Bram]

Alright, today we spoke with a very nice local man who's proffession is building and installing fireplaces. He will be able to supply us with a Cast Iron cook top!

[Bram]

Hey there everyone, thought I'd give an update on how the WRC is performing after the installing of the cast iron I spoke about above. Since I last wrote on this forum we are immensely grateful to have received our first daughter! She is healthy and happy and full of joy ^_^



So, about the stove. It takes about 3-4 hours and 2 baskets of wood to heat up from the temp it has after radiating into the house during the day.

We usually start a fire around 19:00 and by 22:00 the bench and room are toasty warm. Keep in mind that we treat this as a woodstove, not a RMH. In that we don't burn a full load to super-charge the bench as quickly as possible but rather like watching the fire through the little window and feed the fire as is needed. It still seems to burn at full efficiency, so props again to matthewwalker The heat lasts throughout the night and by morning the air temperature has dropped quite a bit. One can still remain toasty warm by sitting on the mass, but the room tends to be 'light sweater and slippers temperature'. This is with outside temperatures hovering between 0 and 5 degrees C at night. I have one of those laser temperature sensors and I measured the surface of the wall across from the WRC to be 32 degrees C. Which is quite a feat when you look at the average Greek home made of concrete and brick like ours. The weather is warming up around here, we are moving into spring. And when we visit my partner's parents the house is still freezing cold compared to our home. They pay 2-300 euro's in diesel every winter. In short; not only does the WRC manage to heat up the bench, it ends up charging up the whole house with heat and you notice the difference immediately when you enter a home of similar build quality. One thing to keep in mind is that our home has insulated (exulated? small layer of insulation on the outside) walls, but the main difference comes from the radiant heat of the WRC I am sure.

Pictures of the build can be found here: photos.google.com/share/AF1QipPbaDQ-elPPxT9PMxOl9CSU1PdHZH0dvoP7CazeggbwbF0Vj9zPeVrUI5VOIXIZcQ?key=cHQ4YVFvZHoyYkFBcnplbXMtamU5ZG1NaWVRQ2xn

[patamos]

Congratulations on the arrival of your daughter

And good to hear your stove is performing well. An exsulated house is ideal for radiant mass heating applications. The whole interior becomes the heat absorbing, storing and sharing medium...

Happy firing !!

[Bram]

Here is a video of how this stove performed after three years:

www.youtube.com/watch?v=A4z0u6-n4fU