36' low dome neapolitan style

[Gulf]

You would probably find that initially removing the center brick much more difficult than getting it back in place.

I probably had one of the first easily adjustable ITs. My intentions were to do exactly what you describe. However, I had guaged my inner arch with the radius of the IT. So, I decided that I would begin adjusting after I cleared the inner arch. Turns out that I never did adjust the IT. If it made any diference in efficiency, I'll never know.

Welding is above my paygrade. But, I would insulate the entry.

[MarvinG]

Hi Gulf,

Today I improved my IT, and yes - It also seemed easier to properly level it, rather than adjusting the length all the time. Since I have this whole for the burner, taking out the stones was super easy.
Now everything should be quite neat I hope. Many thanks for your input!

Thinking ahead a bit: My oven pipe has 15cm in Diameter. To me it seems to be the easiest to weld a little metal cast from squared to round which I will put on top of my vent?
Shall i go along the oven first to keep some more heat inside or just straight up from the vent?
Is there anything special I have to keep in mind when mounting the metal to the bricks due to expansion of materials?
Thanks

[Gulf]

I'm sure your did fine on the IT. However, the pics loaded too smal for me to really see enough detail.

I did an all masonry chimney/flue. It would be best if someone else jumps in for advice on your metal work. It also sounds like you may have read some posts about the pros and cons of a squirrel tail. That too is above my paygrade lol..

[MarkJerling]

I found I liked the aesthetics of a squirrel tail flue design. Feel free to look at my fireplace drawings to see how I constructed the flue - brick to pipe transition.

[MarvinG]

Thank you for your answers!

Yes, I again strugelled with uploading the pictures... Although I uploaded them normally only the thumbnail would show?!
Ah, it's called squirrel tail :-). Is it more for aesthetical reasons, (to have the pipe in the center of the oven, or does it really make a difference of the performance as well?

Another question came up. What is the rule of thumb, from what row shall I start cutting bricks on (make their width smaller) that the gaps on the outside is minimized?
I tryed again with the pictures, it somehow only works if the pics are ultra small.

Thanks
Marvin

[MarvinG]

Good Evening, or Good Morning I guess
I have been working again today, here are some updates.

Since I am working with a 2600 Watt Bosch angle grinder with a diamond blade its probalby not the most precise work here on the forum, but it seems it's pretty quick. I hope I did the important things right. That's at least how I understood from other threads how the arch should intersect with the dome. The post from Mongota's build helped me alot here.

Any thoughs, comments?

I use a refractory mortar which I found here - not much choice though. It is gluey, but not crazy gluey like clay for ecample. Especially when I move higher up tomorrow, I thought I could add the incredibly fine sawdust from the bricks to it to make it stickyer? Or would you not recommend that?
I also have many small off-cuts from the first round bricks. Shall I but these little wedges between the bricks of the next round, or only fill it with mortar?

Thanks!

[MarkJerling]

Thank you for your answers!

Yes, I again strugelled with uploading the pictures... Although I uploaded them normally only the thumbnail would show?!
Ah, it's called squirrel tail :-). Is it more for aesthetical reasons, (to have the pipe in the center of the oven, or does it really make a difference of the performance as well?

Another question came up. What is the rule of thumb, from what row shall I start cutting bricks on (make their width smaller) that the gaps on the outside is minimized?
I tryed again with the pictures, it somehow only works if the pics are ultra small.

Thanks
Marvin

You're making good progress. As for the squirrel tail. I'm not sure how much heat it contributes, but some say that it helps to heat the dome faster. In my case, I did it mainly for aesthetical reasons as, if I did flue straight up, the flue would have been directly in front of a window. The other reason is that I have a 'know it all' friend who I knew would tell me I've done it all wrong in that he would think, looking at it, that the flue goes straight up from the top of the dome. And, of course, he did!

[Gulf]

Pics at an angle can be a little decieving. But, I have to ask,( are you through cutting the ID radius of the dome on your inner arch)?

Most store bought refractory mortars (refaractory cements) are only recommended for narrow joints of up to 1/4". Wedges are good as long as you place and completely fill the joints as you go. For larger joints, you may want to add some of the saw cutting dust as you described. But, with an angle grinder, you wont capture enough of that to keep up with the work on the dome. Much of it will blow a way with the wind. You may want to think about switching to the home brew recipe.

[MarvinG]

Good Morning!

MarkJerling : I read your thread and wanted to ask: How was this dimensioning? I have a 36 inch dome, therefore went for a 6 inch Pipe, how big should the opening of the exhaust from the arch be, and how high/wide would the squirrel be, before entereing into the pipe? What what I was also interested in: How did you "cover" the exhaust channel on the dome? with steel?

Thanks

@Gulf: I see, so I made quite a mistake with this larger Joints. Some def. are 1 inch wide in the 2nd course. Would you reopen these? You might be laughing, but I have to cut everything in my 20m2 room, so yes - the good thing is the dust cannot go far ;-). I have collected around 6 kg or / 2-3 liters so far I would say...
The thing is, that I struggle to get materials, first of all because of the lockdown, but secondly also because the only thing which I can buy here is "schamotti" which is somehow a premixed grey mortar which was very common in soviet union, but nobody could tell me what it really is. I was told it is kind of a clay to burn - but so far I did not trust it. What would you recommend?
I will take a picture today of what mortar I use. It has some technical informations which I did not really understand but might tell you something.

Yes. I tried to get the IT extended and set the cutting points on the bottom side of the stones, as well as on the upper side. It is not very precise but I assume I can always customize the bricks to fit there if Id did it wrong. I have to say, that in this picture, the stones are just roughly put in place to see how it looks, it's not the final position.


Thanks
Marvin

[MarkJerling]

MarkJerling : I read your thread and wanted to ask: How was this dimensioning? I have a 36 inch dome, therefore went for a 6 inch Pipe, how big should the opening of the exhaust from the arch be, and how high/wide would the squirrel be, before entereing into the pipe? What what I was also interested in: How did you "cover" the exhaust channel on the dome? with steel?

If your flue pipe is 6 inches, then 12" x 4" would be more than big enough for the flue gather and 'channel'. I roofed my channel with some large fire bricks (well, they were fire brick material but were more like large tiles) that I had. Feel free to look at my build photos. I would not introduce steel as the steel will move very differently to the rest. An alternative would be to arch the channel with bricks or to do a casting of fire cement with fibreglass reinforcing, using AR fibreglass mesh, thereby making slabs that can span over the channel. If you make the intake a bit larger, it will probably draw better. My intake is a little small and if I did it again I'd make it the full door width and about 4" wide.

[MarvinG]

Ok, my opening is around 17 inch wide. Is the logic, that the 6 inch pipe, equals (3*3*3.14) so roughly 28 square inch. Shall my flue gather and the channel therefore not be at least this surface, or preferably 20% more?
If so, it would be enough to make it 8 inch wide and 4 inch "high"? I shall also mention, that the whole chimney pipe (which as a few angles of course) has a difference in hight of roughly 4 meters - so it should create quite a bit of flow.
Thanks!

[Gulf]

I had a little dejavu moment when I read the term shamotti. I searched the forum and found a german term "schamotte" in this thread by CvC at (Homebew?).

[SableSprings]

Looking good Marvin. Do remember when dry stacking that you need to use some spacers to "imatate" the mortar. It doesn't seem like a big deal, but those little mortar joints add up. Also on the squirrel tail flue design you want to think about creosote buildup & cleanout...stay away from sharp angles & collection corners.

[MarvinG]

I had a little dejavu moment when I read the term shamotti. I searched the forum and found a german term "schamotte" in this thread by CvC at (Homebew?).

very intersting Gulf. Just read through. Today we found a local georgian Fireplace builder who said: This schamotti is "overburnt" clay. So I guess, that is the fire clay!

So now my question is: since I still have on 25kg bag of the (expensive refractory mortar) Shall I just add schamotti/and or sawdust, or shall I switch to homebrew? 3111 (sand, fireclay, portland cement, lime)
Today I did the first row and my arch with added sawdust in a 1:4 ratio roughly.



Unfortunately the arch does not win a beauty price, but its half way ok. I cut the wrong (slightly bigger bricks at the edges of the opening, so it looks a bit ugly. from what you will see in the very end I think its pretty good. I have also about a 1 inch gap between the IT and the arch, as well as the angle is not very correct, but does that matter? I mean I will customize these bricks anyway...

[MarvinG]

Looking good Marvin. Do remember when dry stacking that you need to use some spacers to "imatate" the mortar. It doesn't seem like a big deal, but those little mortar joints add up. Also on the squirrel tail flue design you want to think about creosote buildup & cleanout...stay away from sharp angles & collection corners.

Got it SableSprings, thanks! makes total sense. But i mean, cleaning would be quite challenging, right? I plan to run the oven with natural gas, just got the "oven passport" yesterday. Then this issue is heavily reduced I assume. Here and there I will add a log for the taste. But since the oven is supposed to perform every day commercially I don't want to have the effort of firing the wood fire every day.
Regarding the squirrel Flue I will stick to the attached plans of MarkJerling and make it slightly smaller. Since I would like to avoid any glass fibres or so - I will look out for thin fireclay tiles or st. like that to cover it.