Flexible pipes and bottle insulation

Hi

I'm thinking to build a rocket stove mass heater but instead of the bricks or metal pipes, I'd like to use those flexible tubes. Would they work? And what about the insulate base layer made with glass bottles? A friend is using this technique for the insulated layer in his cob ovens.

many thanks from Sicily, Italy
Roberto

I have just asked this about the flexible pipe, because it is aluminum and may be too week in the long run.

I can tell that I saw it, and it was starting just after the fire place. But it was not a rocket stove.

Anyone have more info on this? I'm interested in running stainless steel chimney liner in cob as an exhaust from a traditional woodstove. The run is up through a loft so has a lot of vertical lift, just wondering how this stuff would hold up when compared to regular wood stove pipe.

Reason being that I have a long 20' run up and around a long curved wall and normal fittings would be a huge hassle.

Thanks!

Which type of flexible pipe?

There is flexible chimney liner (usually stainless) that is made for re-lining old masonry chimneys. EXPENSIVE, but much easier to snake around bends in old multi-stack chimneys. It will hold up, maybe even stronger than standard pipe because the corregations will prevent denting/collapse when throwing cob on it.

There is the flexible venting pipe, usually aluminum that is oversized dryer vent. CHEAP, may be strong enough to hold the cob if you are careful. May melt away if you get it too hot so you better make sure your cob is really good and no leaks.

Then there is the flex vent that is a spring wire and foiled mylar that used to be sold as dryer vent but failed even at those temperatures. It is OK for hot air ducting like some stoves/inserts with blower fans. Not going to hold up to cobbing.

Thank you, good info!

I was thinking of using the expensive stainless steel chimney liner stuff. Basically this is being installed in an underground structure so I can't go through the roof and good exit points are difficult to find. My current plan involves snaking up and around a curved loft wall to get out. It's about a 20' run but isn't a very tight curve so I'm hoping I can clean it with flexible rods and appropriate plastic brush. I only have about a foot of space to work with in some areas (running under beams) and the pipe is 6" so there won't be a whole lot of cob encasing it at these points. That's why I was thinking I'd go with the thicker, expensive, stainless stuff. Still not sure it will work. The wall is non-combustible but it will be running under the ceiling beams every 6 feet which are wood . In my case, the cob idea was mostly about insulating the pipe from the ceiling with the mass as a happy side effect. I was going to use vermiculite or some other insulation in there as well.


I'm fairly new to stove stuff so please call me out if there are any obvious problems.