My first RMH out of 4" sewage pipe

In germany the sewage pipes has been out of stoneware (german: Steinzeug) bevore everything is now out of PVC.
It's easy and cheap to get these old stoneware pipes. The smalest size is 10cm inside (about 4"). Because I want to heat a small room I want to build a small RMH.
Here are some pictures from the first try.

The insulation is out of foamglas-gravel fixed with a metall net.
About foam glas I wrote here:
https://permies.com/t/20073/wofati-earth-berm/Foam-Glas

The first fire was quiet wet because of rain...
But I believe that the stoneware would stand the heat. It was produced in fire. The inside is glaze out of meltet glas. (right english?)

Has anybody some experience with such material and/or such small sized combustion pipe?

Have a look at:
http://donkey32.proboards.com/index.cgi?board=experiment&action=display&thread=511

The 6" core introduced at Page 5 Reply #65 can output about 25 Kw/h.
Downsized to 4" about 10 Kw/h should still be possible.

mein freund:
"It was produced in fire. The inside is glaze out of meltet glas melted glass. (right english?) "

love the way you insulated the riser on your heater. very cool and similar to how I have insulated the forge in my backyard. Viel Gluck!

Since the insulation is already glass, can't we just use that on the inside?
If not we could still use foam-glass bricks, if they weren't so freaking expensive!

cool!

Balint Bartuszek wrote:Since the insulation is already glass, can't we just use that on the inside?
If not we could still use foam-glass bricks, if they weren't so freaking expensive!

From the heat the foam glass would be right in the inside. But what about the metall net? Would this stand the heat?
And what about the friction between air and foam glass?

Two heavy metal pipes and foam glass between would work easy. But glass allone? What about pre produced foam-glass heat risers?

Konstantin Kirsch wrote:
From the heat the foam glass would be right in the inside. But what about the metall net? Would this stand the heat?
And what about the friction between air and foam glass?

Two heavy metal pipes and foam glass between would work easy. But glass allone? What about pre produced foam-glass heat risers?

The net would not stand that heat for long. I was thinking more like using clay to bind the pieces together.
Here is how i imagined it:
We take a paper tube and glue the first layer of foam glass on its surface, then we use soft clay to fill the gaps between the glass pieces and then wrap some wire on this stuff and use the normal perlit-cob to make the wall thicker.

I don't like to put thick steel pipes in the hot parts, as these warm up slowly. But i admit they should last longer than most materials. I like to know how foam glass would hold up to the heat.
Would make for real nice pre-made cores and risers if it does.

Balint Bartuszek wrote:
I like to know how foam glass would hold up to the heat.

Likely it will not resist direct contact to the fire.
Cheap glass contains lots of flux to reduce productions costs by lowering the melting point.
The melting point could be as low as 800°C.
Without flux the melting point would be around 1500°C.
With some silicates even above 2000°C

karol kerl wrote:

Balint Bartuszek wrote:
I like to know how foam glass would hold up to the heat.

Likely it will not resist direct contact to the fire.
Cheap glass contains lots of flux to reduce productions costs by lowering the melting point.
The melting point could be as low as 800°C.
Without flux the melting point would be around 1500°C.
With some silicates even above 2000°C

Then i have to modify my idea to use high temp concrete on the inner layer.