Peter van den Berg

John C Daley wrote:Are there any plans or notes available for The Shorty please?

Hi John, yes there are. Here's the link to a post in Donkey's forum that explains it all, as far as I am aware of. Only the measurement of the port's depth is not correct and largely unimportant. This depth follows from the thickness of the bricks that's been used and the thickness of the liner inside the riser box.
https://donkey32.proboards.com/post/39715/thread
Of course this is all about the combustion core, it's by no means a complete heater. It would be best to explain in more detail what your requirements are, what size of (fire) bricks are available to you, what size of chimney is already there or not at all, etcetera.

In the latter picture the black stove pipe seems to be absent so the outer cage of chicken wire will hold it together instead. Now I understand what Thomas meant, a larger stove pipe on the outside of the wool would be much easier.

Looks good!
It's a delight to see a build-to-spec heater, it appears to run right out of the box, so to speak. No wonder the chimney is spewing vapor clouds into the air, 81 ºF isn't enough to keep the exhaust gases above condensation temperature. That puddle of water around the exhaust is the tell-tale sign, the whole of the heater has a lot of water in it. Could take some time to get rid of it all.
Keep us posted.

thomas rubino wrote:The roof supports are currently just sitting there and can easily be flipped.
In the past I have only seen them with the smooth side up.
We will flip them this morning after wrapping.

Best to leave out the wrapping altogether, only thin superwool or ceramic paper between any steel and brick surfaces. This will simplify the build quite a bit, I've found out. The upright flange of the T will be out of the highest heat and as such will be protected. Wrapping in superwool means moisture could be trapped, causing rust. All bare steel will be coated with a nice thin layer of tar, especially in the running-in period, corrosion won't be an issue this way.

Thomas, sorry to say, I'd think it would be best to mention some possibly negative constructions.
As it looks like, the bypass valve is placed higher than the riser's top. Which means thermal stress will be higher on the metal, this won't melt or anything, but the steel plate could warp.

And, the support for the bell ceiling is used upside down, in my opinion. The double flange is hanging down now, so this will be in the highest heat what the riser can deliver. But, perhaps it won't sag because of the doubled flange. There's also another effect though, the gas stream along the ceiling could be hampered, due to the highly irregular surface. This isn't mentioned before, although I've seen it in a number of occasions where the ceiling wasn't reasonably smooth, both the front and rear walls lagged behind in warming up. The heater in the cabin has the same construction, I know that, but there's an entirely different core in there, not blasting up vertically.

Just to let you know, that's all.

Can you use a rocket mass heater/stove to provide the heat for an in floor heating system?
Historically the Chinese and Koreans used an in floor heating system using a fire outside the home that heated flues under the home.

The systems you mention here are broadly following the lines of a roman hypocaust. Essentially a hollow floor where the gas stream to the chimney flows, (or chimneys, like hypocaust) through channels or under the entire floor. All systems like that has a raised floor.

Streching this idea a bit, you would need a pit, cellar of basement where the combustion core is located, feeding the hollow floor. This could be done, with the use of a reversed Shorty core. This is a latest-generation batchrocket core sporting a very low riser that won't exit at the top but at the front or back instead.
Have a look at the workshop report from this spring in France. The core that was used there happened to be a reversed sidewinder, and it worked flawlessly.

Looks correct so far, don't forget the clean-out.

Hi Thomas, I think I spotted the first mistake. The exhaust box, for want of a better term, is too cramped, it should project at least half a brick further to the rear. As it is, there's no chance that the projected stove pipe could go straight up, the outer skin's thickness would prevent that. The picture of the dry stacked layout shows this very clearly.

It might be that the current stove pipe position allows it to go straight up. In that case, the whole of the inner skin should shift (at least) half a brick to the front.

Cerbu Ulea wrote:is there the roar you know? https://www.youtube.com/shorts/KF6lO16Ve1I
the smoke /steam is low https://www.youtube.com/shorts/64-sAlZ1mkw , gas temperature in the open damper around 50 C, the bell heats fine, the terracotta wall reached about 40 C(i did not install outside control yet, left the bypass fixed a thin crack open)

It's a low rumbling, could be louder, I'd think. Gas temperature in the chimney could be higher, 58 ºC is the bare minimum to avoid condensation. Steam from the chimney is (mostly) absent, which means the heater is getting dry now. The system clearly works, congratulations!

Cerbu Ulea wrote:LE: the end of the burn temperatures , it was already warm from the days before https://www.youtube.com/shorts/H6zZ81-n59E , I think it requires the second  skin, splits are prepared

The outside of the heater is reaching 70 ºC and more, a second skin is required, in my opinion. Maybe not even splits, I would go for full bricks. What are the outside temperatures in a normal winter, where you live?

Cerbu Ulea wrote:there where 2 degrees C  , It was transparent to white , I just think it is steam as I increased the fuel and the bell finishes drying , tomorrow will be 2 thirds full. I will record in silence to listen if the roar is good.

This amount of visable  water vapor is quite normal while drying a masonry heater, given the low temperature outside. Keep in mind, fuel in the firebox loaded not higher than the port. And a bit away from the rear wall, this will give the best results. To my eye, the fuel could be more compact. The roar of a Shorty core is not as loud as compared to a first-generation batchrocket, although it's still very much there.

Cerbu Ulea wrote:Please tell me if a k probe inserted at the chimney's vertical start is good, or where else to measure , there is no pipe exposed, all flue is in-wall bricks

A k-thermocoupler in the start of vertical is good, normally I use a pen thermometer and place it at eye level though the chimney's wall. If you have a digital 2-channel thermometer, another one high in the bell is also a good indication.