This is what I ended up doing

[whazzatt]

After asking questions in this post and this post, this is what I ended up doing.

Used it 5 times now for between 2 and 4 hours - works excellently. Cob cracking a bit. Clay/sand plaster holding up 100%. The thing will be plastered at some point with a more elastic cob plaster; gonna use it as is for the coming winter first.

[Vortex]

Whazzatt, you seem to have posted an image of a list of url's. I doubt anyone will want to manually type all those in to their browser.

If you take your list and add [url] to the front of each one and [/url] to the end, they will display as links like this:


drive.google.com/uc?export=view&id=1xG9HSARIREad2cLNRjvRKvHnGjhIOYIf

[Jura]

I can see all the photos display properly.
And the OP seems not to have edited his post so maybe sth's wrong on ur side, hm?

[Vortex]

Jura, Just tried it in Opera browser, I get all the images displaying OK there, but in Firefox it looks like a list of url's, but I can't click on, highlight or copy any of them.

Whazzatt, Your stove looks great. Is that a copper water tank you're using for the barrel?

[drooster]

I see the images, but I'm using an old Opera.

Is that a copper water tank for barrel?

[Vortex]

I tracked it down to Kaspersky Anti-Virus, if I turn Kaspersky off I can see the images OK - Weird.

copper has a melting point of 1085*C. Will it stand up the the temps of the top of a riser OK?

[Dan (Upstate NY, USA)]

Looks like a steel tank to me, and I just noticed the cat crawling out of the feed box. Talk about alternative fuels!

[Jura]

Stewed with garlic and ginger the cat would be more  palatable than just roasted in fur ;-D

[travis]

Good job! Looks like a nice beginning.

[whazzatt]

Glad your image display issue was sorted out Vortex.

Drooster, Vortex, and Wolf: The tank is steel, thick steel. An old water 'geyser' - at least that's what they are called in South Africa; 'boiler' elsewhere, though that kinda makes me think of old American horror films for some reason.

I would have preferred a flat topped steel barrel but couldn't find one with the appropriately smaller circumference. Will keep looking and if I find one I might change the tank for a barrel at the start of next summer.

I just realised that the ceramic fiber board riser is pictured without the foil I rolled around it. So it's not a naked fiber board riser in there.

Oh, and the cat survived!

[Orange]

the boiler looks way better than the barrel. You can cut the top and weld a flat steel plate if you want to cook.

[whazzatt]

Mar 12, 2018 3:01:27 GMT -8 Orange said:

the boiler looks way better than the barrel. You can cut the top and weld a flat steel plate if you want to cook.

Thanks, I reckon I'll get that done sometime. 

[drooster]

I think the steel tank looks great.

[Orange]

in the j-tube the flames dont really get up in the riser and the highest temperatures and combustion are done in the firebox. Does it make sense that the firebox shoud be better insulated than the riser?

[whazzatt]

Mar 14, 2018 1:13:56 GMT -8 Orange said:

in the j-tube the flames dont really get up in the riser and the highest temperatures and combustion are done in the firebox. Does it make sense that the firebox shoud be better insulated than the riser?

Assuming I understand your comment and question (!), yes, it does make sense that the firebox is well insulated.

But I didn't do this!

Consequently, the heat really emanates from around the firebox, which I think is appropriate for my situation. I will add a lot more cob around it eventually, not as insulation, but to hold heat. I'm sure that in other situations, insulation around the burn chamber would be necessary.

I am extremely happy with the way the unit burns and emanates heat, even through the burn box. I imagine that if sizing throughout a unit is uniform, then an un-insulated and hot burn box could be a problem, causing backburn.

But this system is roughly a 240 cm2 CSA burn feed, followed by a 300 cm2 CSA riser, and a whopping 435 cm2 CSA flue. Probably not ideal, as I'm sure I'll be told, but this unit has a serious pull to it - no chance of backburn. 

What's nice is that I can close up the feed mouth as much as possible and the burn slows.