36" Pompeii Dome - Thailand

[danhem]

Nice! Yes I agree. when I built my dome and saw it coming together I was awestruck on how cool it looked. The more you keep building the cooler it looks because right now you see the way it looks getting fat and then it starts to narrow again as you close it up. I couldn't stop staring at mine. LOL.

Ricky

Amazing how the thing evolves from a pain in the ass to a thing of beauty....sure I'll be cussing it again before long.

[Mongo]

I couldn't stop staring at mine. LOL.

Ricky

Looking good. I've spent hours staring at mine. That's funny. The transition from ring to dome is awsome.

[danhem]

Looking good. I've spent hours staring at mine. That's funny. The transition from ring to dome is awsome.

Yes very much looking forward to the next couple of days. Just enjoying the build without the frustrations and complexities.

prepared for more of the troubled times some time soon...but for now it’s all good

[brad mole]

Sorry for replying so late to the thread, i just got around to reading your build after your comment in my build thread, but looks like youve already sorted the problem and done a great job too, its all pretty easy from now on up until you make your chimney transition! good luck!

[danhem]

Sorry for replying so late to the thread, i just got around to reading your build after your comment in my build thread, but looks like youve already sorted the problem and done a great job too, its all pretty easy from now on up until you make your chimney transition! good luck!

Thanks Brad, yes things have somehow come together. Moving on now up the courses and will spend the coming weekend on what the hell to do with the chimney!

[danhem]

Making progress now, slowly but surely. In to the 7th course and hope to close in on the run over the arch tomorrow. Seems that as the courses go up each brick requires a cut. Not sure Ive mastered the art of the bevel as my joints are not a tight as many others Ive seen here on the forum. However I'm not too worried as I'm just simply glad to be closing in on the dome closure.

My attention is now focussed on doing a good and neat job of the outer-arch and chimney. I'm guessing that the outer-arch will be easier than the inner, but I'm currently unsure on the specifics of the vent area.....surely this part of the build doesnt deliver the same level of head damage that the inner-arch gave?

[UtahBeehiver]

The opening in the top of the vent chamber should have at least the same area as the ID of the chimney, 8" ID chimney equals 3..14 x 4 x 4 or 50.14 sq inches so the opening in the vent arch should be at least this amount with a smooth transition from rectangular shape to square or round..

[danhem]

The opening in the top of the vent chamber should have at least the same area as the ID of the chimney, 8" ID chimney equals 3..14 x 4 x 4 or 50.14 sq inches so the opening in the vent arch should be at least this amount with a smooth transition from rectangular shape to square or round..

OK thanks, I think I've managed to work it out from your explanation and from looking at the pics in your build. Many thanks.

Also I see many builds use a heat break. Is this an essential part of the build?

[UtahBeehiver]

I did them, both floor and dome to arch. Are they worth the effort as far a effectiveness, can't say for sure since I do not have a baseline to work from. That said, floor and dome and a good insulated door are based on members experiences to be the most effective heat retention measures. Gulf did a nice "L" shaped vent design for his insulated archway. So kinda up to you, necessary, no but nice non the less.

[Yokosuka dweller]

I copied Utah's floor heatbreak and JR's (and others') L-shape brick heatbreak around the dome opening arch. I can say that when firing, there is a 20-30% temp difference between the heat breaks. Of course the distance from the fire itself must make a difference too, but I think heatbreaks have some significance. But as DavidS has said many times, it is more an expansion break than purely a heat break so that's also an advantage to reduce risk of cracking arch through these heatbreaks (although my arch developed hairline cracks eventually anyway). All this being said a well insulated door will break more heat than either of those heat breaks.

[danhem]

I copied Utah's floor heatbreak and JR's (and others') L-shape brick heatbreak around the dome opening arch. I can say that when firing, there is a 20-30% temp difference between the heat breaks. Of course the distance from the fire itself must make a difference too, but I think heatbreaks have some significance. But as DavidS has said many times, it is more an expansion break than purely a heat break so that's also an advantage to reduce risk of cracking arch through these heatbreaks (although my arch developed hairline cracks eventually anyway). All this being said a well insulated door will break more heat than either of those heat breaks.

Okay thanks. Still trying to weigh up whether to add the heat break or not.

Main factor being what material to use. I see most have used some kind of ceramic rope. The supplier here in Bangkok doesn’t stock such a thing. They do supply RockWool - not sure what it is or whether it will serve the purpose of a heat break?

I did wonder whether the left over ceramic fiber board would be ok to use also.

[Yokosuka dweller]

Rockwool wouldn't work I think - not rated for high enough temps I'd say. I didn't use ceramic board so not sure about its consistency, but i guess it would work for a floor heat break if you cover it with something that is abrasion resistant. Anyways for my floor heat break I merely used a square stainless tube and filled the area below it with perlite/cement mix and left air inside the tube. For the arch heat break I used ceramic fiberglass rope. It's stuff you don't want in your food which is why the L-shape cut allows you to place it on the top of the inner arch. I googled a bit and found two websites in thai that describe heat resistant gasket rope. One has asbestos, which I didn't think people used anymore. But given 'this is Thailand', some differences still exist. If no other option, then that would be an option.

https://www.ntiheatprotection.com/ro...-for-750c.html

https://www.nanasupplier.com/kimtech/p-187102

Edit: here is another supplier that has higher temp rates ropes: https://truesealcorp.com/products/insulating-textile/

But for these you might have to call and talk to them, I could imagine that with the current lack of global imports situation they may not have it.

[danhem]

Many thanks Yokosuka, I will get on to True Seal Corp today. Seems like the expansion benefits of the heat break could help to save my oven from failing mortar..

I’m nervous as hell about the mortar failing during the curing process. So much so that I’ve already prepared myself to break the oven down brick by brick and to source the ingredients for the home brew. Seems that SvH has been through 2 builds in Thailand already and is preparing a third with locally sourced home brew materials.

Should I have to break it down, at least I could correct a few mistakes and the rebuild should be fairly easy assuming I can recover all/most of the cut bricks (cutting has been unbelievably time consuming).

I see you build is coming along nicely, great picture of the oven with fire and all it’s glory. I’m longing for the same same day.

Out of interest, where did you order the chimney from, I’m guessing it came from overseas, even from FB itself?

PS. - you may remember that I had a trip planned to Japan in March this year. Cancelled unfortunately due to Covid. I managed to recover our flights and accommodation in the form of credit so watching the situation over there carefully ready to book the trip again for March 2021....hopefully. I see Hokkaido is facing some sort of second wave crisis.

[danhem]

So finally closed the dome in today. My 7 year old boy was on hand to smash the key stone home. The stone itself was one of the easier cuts Ive had to make over the past couple of days. Courses 9,10 and 11 put my new found (still finding) masonry skills to the test, mindful that the tighter things fit together the better, I made a special effort on cutting the last brick on each course with as tight a fit a possible, even to the point where I had to hammer the brick home for a tight fit. Seemed to work out fine if not entirely by the textbook.

The keystone is a single 4.5" brick, cut into a skewed six-sided shape. It would be unfair to call it hexagon in its truest form but it basically has 6 sides and, most importantly fits in its hole very snug.

All in all thus far Im happy with the build. My DIY skills are next to none and with the Covid store closures and simple lack of adequate brick cutting machinery here in Thailand, Ive managed to overcome the inner arch conundrum and have a dome that is a near perfect 18" radius.

[danhem]

Ive been saying it for a week or so now but I am finally ready to move on with the vent and chimney. I think Im clear on what to do and see the process to be much simpler than the inner arch. Since my inner arch bricks extend fairly deeply away from the oven i will use the outside of the inner arch as part of the vent opening and build the outer arch accordingly.

I have around 1/2 brick from the back of the inner arch brick and will lay another full brick to make a vent depth of 13.5" from the oven opening point (center line of oven to 18" radius point). The outer arch will follow the inner arch design - 3 bricks up flush to the inner arch back side bricks before the arc begins. To accommodate the vent opening i have mapped out an area of 50 sq inches. At this point in the arc I will use 1/2 bricks for the outer arch to leave a gap between the back of the inner arch bricks and the outer arch bricks (taken this idea from Utahbeehiver's design). Once in place the transition for the flue will hopefully sit firmly on top of the arches.

Looking at anchor plates and pipe options. I guess the FB store is as good a place as any to start. With that in mind - for a 36" oven, is an 8" pipe the best option for better flow over a 6" pipe?

Thank,

Danny.