Jody Vanden

thomas rubino wrote:No, not a problem at all. Rather handy to have 2" around.  
But for a riser she would need a 10" pipe for her 6" riser.
After reading Matt Walkers site, even 1/2" blanket will work, but the 1" works well for pipe sizing.

Yeah but that's pretty much the only good quality I found that I can get in France. But I struggle finding a tube of 10 inch. I might have to do one with a sheet of metal with some rivets or screwed in. I think this might be the easiest solution for me :(

ps: yeah I know Jodie Foster is a girl, but I am not hehe I am different :)

Mark Brunnr wrote:
Edit: the interface where the burn tunnel bricks and the square opening meet the round riser is a point where the metal pipe could be exposed to high heat, I'd make sure that you use bricks cut and fitted so that no metal is exposed to direct heat. Some will cob a few bricks around the riser to hold it in place with friction, so perhaps a layer of fiber blanket cut to shape that the riser sits on would help too?

exactly what I was looking for. I was like how will the metal not be in contact with the heat at the bottom!
I think I found for people in France the correct one Superwook 2" for 23euros + 16.5eur shipping. so 44 usd all together. looks cheap as when I check some links here
https://www.amazon.fr/Couverture-Fibre-C%C3%A9ramique-1000-610/dp/B00XMWI7AS

Mark Brunnr wrote:You should actually be ok with the wire not melting when used outside the riser buy inside the barrel, as the temperature drops a lot as the gasses hit the barrel top. Many people have used chicken wire to wrap around their insulation and it has worked well.

I plan to make a 6" system with the 5 minute riser design, using a 8" duct. I would give myself an extra inch clearance between the riser and barrel in case any ash accumulates on top of the superwool.

how did you go Mark? is the 8" tube enough for a 6" rocket stove? or is too big? how tall is your tube inside the barrel?

Any other feedback on this riser type? something not expected after 1 year?
planning on changing my brick riser which is not tall enough and insulated with vermiculite which might not help to have a nice burn in the barrel.
thanks

cool thanks so much for your help Thomas! really valuable info. I was trying to find why this wasn't working properly.

I think I will give a go to the 5min riser. It will help to have more space in the barrel for the fumes to circulate as I have a brick riser + vermiculite around it with a metal sheet.

hey Thomas,

my pipes in the bench are 6 inches stainless steal pipes

The measurement for the feed tube size are 6.3'' x 7.1'' so I guess I am 6.7 '' square
For the burn chamber I read in the book that it should not be tool long

Rocket Mass Heater Overview and Terms page 7

Length: The minimum burn tunnel
length is whatever is necessary to tunnel

under the bell. With a smaller barrel or cus-
tom bell, the burn tunnel could be shorter

without causing problems, but the bell must
never overhang above the feed.

I guess I should adjust the rocket stove to the 6 inch pipe I have in the bench, I will have a look for the correct dimensions
thanks

thomas rubino wrote:Yes Jody;Since it is creosote, then something is bad off.
Could be dimensions or as Phil suggested it could be your wood is not dry.
You should be getting hotter on top of the barrel.  Because your not, then the temperature in the riser is not getting hot enough to consume the particulates.
That is the only way creosote can get past the riser.
If you can, get us some measurements. All of them. Depth of feed tube , length of burn tunnel roof, height of riser.  Size of core (ie) 7.5 x 7.5 or 5.5 x 5.5)  
What is your riser made off? Properly insulated ?  What is your transition to horizontal area like ?
The 2" riser top gap, should have increased the barrel top temp, So changing it back rite now won't fix your problem.  Later changing it to 3" or more is a good idea.  

- the riser is made of refractory bricks (high temp) and is insulated with vermiculite + metal sheet around it to keep in place (maybe .2in)
I don't understand the transition to horizontal?
From the barrel to the bench, I have this chamber that get's the fumes down. It's diretly connected to the ground (tiles at the bottom). Maybe it's too cold and creates condensation?

I updated the image with the dimensions of the burning chamber

Hi,
Sorry was super busy last couple of weeks...

- I use only dry oak (has dried out 3 years + 2 years in the backyard) so I guess it's not the timber the issue
- the chimney is a maybe 4m high, I put a tube with double wall inside an existing brick chimney. The top is open, water can come in, but I have a T at the bottom before it comes in the bench. No water can come in the bench from the chimney.
- the stove burns quite often. I would say big fire in the morning, then depending on the cold. At least 4h per day I would say.
- it's definitively no fly ash. It's black, sticky and super hard to take out

Hi Thomas,

yes it seems to be creosote. Big black, as hard as rock in the pipes. Really hard to get rid off which is annoying.

Yes my drawing is off. I will try to get the measurement of the inside of the burn tunel.
there are 6 bricks (as I can remember) for the top of the burn tunnel until the heat riser. So it's not that big.

I will come back with dimensions on the drawing.

Maybe I should check that I put more gap again on top of the riser and the barrel

Hi,
I build a rocket stove at my parents place 4 years ago and we are super happy with it.
But it seems that we have some trouble with creosote in the pipe after the rocket stove in the bench.

Let me give some details on how I build it:
I used the book the rocket mass heater, builder's guide from Erica Wisner & Ernie Wisner. The rocket stove is perfectly burning.

I used refractory bricks for the burn tunnel and heat riser and did not insulate the heat riser at the time as I thought the big bricks would do the job.
Pipes are in stainless steel and connected and tapped with aluminum tape. I did not put an angle for the condensation to evacuate. But I won't be able to change that.
Barrel is an old oil barrel. Dimension of the wood feeder,  burning chamber and heat riser are the same.

We already had some creosote in the pipes at the time. So I started by changing the gap between the heat riser and the barrel to reduce it. I reduced it from 8cms to 5cms(3.14in to 2in)
Seemed to not have improve the problem that much in the pipes.
I tried to insulate with a metal + vermiculite around the heat riser.
Did not improve the problem with creosote in the pipes neither

temperature read on the barrel after few hours of burning measured with a laser instrument
top where the heat rise is: 190ºC to 200ºC (374ºF to 392ºF)
top around the barrel: 135ºC (275ºF)
around barrel bottom next to the wood feed: 55ºC (131ºF)

I am not sure what I could check or change now.
Are my pipes too long in the bench?
Is the hash box too big (behind the barrel?
Should I add a small metal pipe to inject oxygen in the heat riser?

thank you so much for the help you could give me. I am a bit out of ideas now.