question about my rocket batch 150

[cedro]

Sono tornato

dopo mesi di vari problemi ho finalmente trovato un giorno per costruire questo progetto.

Ecco le immagini dei miei progressi:
drive.google.com/folderview?id=11KRF18mnu3nzlfhok7ixanO6ZPlgjg-S ho costruito i triangoli di base, tagliato mattoni refrattari e fissato con cemento rifrattario 55,56,57) ho costruito parte dell'ultimo livello, prima
ho fissato il tubo di uscita e poi lo finirò

58) particolari sfere di argilla tra il muro di pietra storto e il cemento cellulare
59) ho fissato il tubo di uscita nel muro


60) Spero che non sia una restrizione?


61,62) la scatola di uscita, è chiusa con lamiera da 2 mm può andare?


63) test di posizione tubo e by-pass


64) ho un problema, come faccio a collegare il tubo con il foglio??


grazie a chi può aiutarmi, a presto

[fiedia]

Hi Cedro,

Your link points to sketchup pictures. It does not look coherent with your post. Is it ok ?

[cedro]

Sorry,
you are right. I changed the link, thank you

[peterberg]

60) i hope it is not a restriction?

I don't know what I am looking at. Is the hole smaller than the chimney?

61,62) the outlet box, is it closed with 2 mm sheet metal can it go?

Yes, you need to weigh it down with some layers of bricks on top of it. But it could be much thinner, like 1 mm as long it is fixed in place by bricks.

64) I have a problem, how do I connect the tube with the sheet??

First: the pipes need to be mounted with the male ends down. Otherwise, black moist will be dripping on the outside of it. In a thinner sheet: cut a hole that's one cm smaller around. Bend a flange all around the circle with a wrench. Do this in small steps, take your time. When the flange is about 45 degrees you can do the rest with a not-too-big hammer. Do several rounds, step by step. Mount the sheet with the flange up and make the thinner end of the stove pipe fit in. Hole too small: hammer a bit more. Hole too wide: hammer it back a bit until it fits.
Thicker sheet: you need to cut a hole that's exactly the right size. No possibility to make it smaller again like in the thinner sheet.

I can see one obvious mistake, sorry. The wall of the bell is built directly on top of the firebox, there's no superwool on top and the sides, only mortar. The firebox will get awfully hot, much more than the bell's wall, and will expand quite a bit. By doing that, the wall will inevitably develop cracks, because of expansion differences. You can get around this by scratching the mortar out, top and sides, and fill the gap with superwool. The entire core, firebox and riser alike, should be separated from the rest of the heater, only exception is the bottom of the core.

[cedro]

I don't know what I am looking at. Is the hole smaller than the chimney?

from the round section (tube diameter 150mm) to the square section (chimney 150mm x 150mm)

Yes, you need to weigh it down with some layers of bricks on top of it. But it could be much thinner, like 1 mm as long it is fixed in place by bricks.


First: the pipes need to be mounted with the male ends down. Otherwise, black moist will be dripping on the outside of it

OK I'll do that

In a thinner sheet: cut a hole that's one cm smaller around. Bend a flange all around the circle with a wrench. Do this in small steps, take your time. When the flange is about 45 degrees you can do the rest with a not-too-big hammer. Do several rounds, step by step. Mount the sheet with the flange up and make the thinner end of the stove pipe fit in. Hole too small: hammer a bit more. Hole too wide: hammer it back a bit until it fits.

Thicker sheet: you need to cut a hole that's exactly the right size. No possibility to make it smaller again like in the thinner sheet.

thank you for your precious help

I can see one obvious mistake, sorry. The wall of the bell is built directly on top of the firebox, there's no superwool on top and the sides, only mortar. The firebox will get awfully hot, much more than the bell's wall, and will expand quite a bit. By doing that, the wall will inevitably develop cracks, because of expansion differences. You can get around this by scratching the mortar out, top and sides, and fill the gap with superwool. The entire core, firebox and riser alike, should be separated from the rest of the heater, only exception is the bottom of the core.

between the firebox and the wall of the bell I put 13 mm of superwool as you can see in images 28-36-38 it's ok? 

[peterberg]

Sept 13, 2023 4:16:07 GMT -8 cedro said:

from the round section (tube diameter 150mm) to the square section (chimney 150mm x 150mm)

OK, I get it. This should be no problem.

between the firebox and the wall of the bell I put 13 mm of superwool as you can see in images 28-36-38 it's ok?

Pictures 28 and 36, yes. The top of the firebox, picture 38, in my opinion is not OK. It looks like the wool was too short and the gaps were filled with mortar. So there's a rigid connection between firebox and bell wall. Of course you can wait it out and see whether or not cracks appear.

Succes!

[cedro]

Pictures 28 and 36, yes. The top of the firebox, picture 38, in my opinion is not OK. It looks like the wool was too short and the gaps were filled with mortar. So there's a rigid connection between firebox and bell wall. Of course you can wait it out and see whether or not cracks appear.

thanks, I think I only used the cement to fix the superwool in place, let's hope so



to connect the outlet pipe and the sheet metal I recovered this piece from an old stove as seen in photos 65 and 66.
diameter 150.
it has two perforated plates in section, I can use them to fix the piece to the sheet metal or I have to remove them because they represent a restrction?
what do you think?
thanks for the valuable advice

[peterberg]

Use the perforated "ears" to fix it to the plate. To me, they look like too thin to act as a restriction in a channel that is going straight up.

[foxtatic]

This build brings up a couple materials questions for me.
1. In photo 55 and 56, I see you put clay brick on the inside and the refractory firebrick on the outside. Shouldn't the firebrick be on the inside where the temperatures are hottest?

2. This is the first time I've seen concrete viewed as an acceptable material for bell construction. It's my understanding that above 300 C degrees, concrete begins to degrade. en.wikipedia.org/wiki/Concrete_degradation#Thermal_damages
I would love to use standard concrete in the bell I am planning. Does heat really drop so rapidly after gasses hit the ceiling that there is on real concern about concrete spalling or otherwise stressing?

[cedro]

Use the perforated "ears" to fix it to the plate. To me, they look like too thin to act as a restriction in a channel that is going straight up.

ok thank, beetwen the two part of iron i put the superwool

This build brings up a couple materials questions for me.

1. In photo 55 and 56, I see you put clay brick on the inside and the refractory firebrick on the outside. Shouldn't the firebrick be on the inside where the temperatures are hottest?

I used firebrick inside and bricks for the outside, in northern Italy the color of the bricks is this

This is the first time I've seen concrete viewed as an acceptable material for bell construction. It's my understanding that above 300 C degrees, concrete begins to degrade. en.wikipedia.org/wiki/Concrete_degradation#Thermal_damages

I would love to use standard concrete in the bell I am planning. Does heat really drop so rapidly after gasses hit the ceiling that there is on real concern about concrete spalling or otherwise stressing?

oops... I didn't ask myself this question. only near the riser I used fireconcrete... let's hope for the best, I'll update you...

[cedro]

hello guys

Here's my construction progress

drive.google.com/drive/folders/11KRF18mnu3nzlfhok7ixanO6ZPlgjg-S?usp=sharing

I finished the gas exitbox:

67) the part with bricks and concrete, I added a pillar to better support the sheet metal

68) I connected the metal parts with superwool and bolts

69) closed the box with sheet metal and concrete



I created a new connection between the wall and the pipe, I made a box to which I will connect the outlet pipe, I was afraid that as I had done before it could be a restriction (photo 70,71,72)



I built the internal layer in refractory bricks with the connection for the by pass, between the pipe and the concrete I put some superwool (photo 73,74,75,76)



what do you think, if I'm wrong please correct me, I will be grateful

[martyn]

You have certainly put in a lot of work!
I am always interested to see different material from different parts of the world, I guess you are somewhere in Europe?

[cedro]

Hi, I'm finally almost finished with the build in north of italy
here are the updates:
77 and 78) I finished the walls of the bell

79) the finished rough bell, after the tests I will plaster it

80,82,83,84,85) here is the ceiling of the bell, first layer with firebricks and super between them, second layer half inch superwool, third layer of bricks and concrete. I also covered the t-bars with superwool fixed with fireconcrete (photo 81)

86) half-inch cast iron combustion chamber roof

and the brick door (I will soon build an iron one)



I started the ignition tests and found several PROBLEMS,

1) whitish smoke comes out of the chimney (photos 87 and 88) could it just be water vapor due to the drying of the cement?

2) the smoke comes out from the ceiling of the bell and from the firebox when I close the by pass, could you help me? is there little draft due to a restriction? perhaps at the point where the pipe enters the wall (photo 72)



Thanks to anyone who can help me understand my mistakes



Thank you

cedric

[peterberg]

Watching the smoke, the picture is ambivalent. The video on the other hand: water vapor, definitely. The water is from the bricks, mortar, fuel and the combustion process on a chemical level produces heat, CO² and water. Of that last one: quite a lot, 0.6 liter from every kilogram of wood.

And since the exhaust gases aren't hot, the water vapor is visible because it condenses in the open air. The process is the same as in burning natural gas, nobody is surprised that a condensing central heating is producing water vapor.

Regarding smoke coming from the bell or firebox: probably water vapor again. Chances are high that this won't smell like wood smoke but cement water instead. Go on heating the thing regularly, it'll all get clear in time.

[firerob]

Congratulations cedro!

I'll have my first fire soon too!