36" Pompeii Dome - Thailand

[danhem]

My advice is to do no harm. Just leave it be. The brick doesn't appear to be tapered so technically it could slide out from top to bottom, but the pressure from the weight of your flue/chimney from above should be transferring into a lateral force onto both sides that should keep that brick in place.

Many thanks. Since posting I've fired the oven a could of times and the brick in question seems to holding it's position well for the time being. Thanks again.

[Mongo]

My advice is to do no harm. Just leave it be. The brick doesn't appear to be tapered so technically it could slide out from top to bottom, but the pressure from the weight of your flue/chimney from above should be transferring into a lateral force onto both sides that should keep that brick in place.

[danhem]

It’s been a while since I’ve been here, guess I’ve been enjoying the power of my WFO….until I noticed a potential issue with the outer arch of my oven.

A crack has grown around one of the bricks and the brick is lose, in the sense that it has a wobble to it when I lightly move it.

I am wondering if there is a way to repair this before anything more serious emerges?

strange that after 18 months of blasting the furnace that this has happened, but happened it has and I’m on a damage limitation exercise now.

any advice is most welcome.

thanks,

danny.

[UtahBeehiver]

Enjoy the fruit of all the planning and construction. Have fun experimenting with your new WFO.

[danhem]

After initially budgeting 6 weeks, 6 months later I am pleased to say that my build is complete. Awaiting a final coat of paint, the dome has scratch/brown stucco layers with AR fiberglass fibers mixed in. The stucco was wrapped in plastic for around 8 days until condensation was no loner visible on the inside of the plastic. After planning for a full 3 weeks before lightning a fire, I gave way to temptation and lit the oven. Thankfully, after two full blown fires the stucco is crack free.

I have also added a granite landing entry, separating the fire bricks with a stainless steel tube, for no other reason than aesthetics. The outdoor counter is dressed in the same granite and gives a wonderful shine to my newest and most favorite toy.

So without further a do - I must give a gigantic thank you to this forum. The contribution of build information from the forum members over the years has been unbelievably valuable. I must have been through most of the builds and have taken inspiration from a number of members to finish my oven.

Special thanks go to UtahBeehiver and david s for taking the time and having patience in pointing me in the right direction when all appeared lost. David I hope you get well soon and are able to continue helping others in the same way you have helped me. Russell, I will remain envious of your build for years to come and have taken as much inspiration from your pictures as I have from your invaluable responses. Thank you so much.

Also many thanks to SvH and Yokosuka dweller for helping me to source the raw materials here in Thailand, Sven I still owe you pizza and free-flow wine next time you are passing Hua Hin

Many thanks again.

Danny.

[danhem]

2 coats of render smoothed over vermicrete Is now complete. It was a satisfy job and I’m please with the way it has turned out.

the dome is now wrapped in plastic. I’m a little unsure on how long to leave the oven wrapped in plastic, guessing 3-4 weeks?

also during this curing time, is it advisable to cease firing the oven? Again guessing, that whilst the vermicrete has recorded little to no heat loss during a fire, and heat that does come through is likely to accelerate the render drying process?

thanks for any advice.

danny.

[danhem]

Been AWOL of late, no other reason than we have had builders in constructing the terrance feature to our back of house 'trattoria'. I've had too many sleepless nights wondering whether a storm was approaching so decided to weather proof the oven area with a roof and enclosed back panel structure. The wooden structure also acts as cover for a nice seating area with a long wooden table, which will add a really nice new area to our house. I'm really pleased with how it has turned out.

So I now approach the final rendering of the dome and have materials in place to begin. Sourced some AR fiber glass strands and a suitable render. I do have a question on the curing of the render layers - I plan on 2 coats (scratch and brown as they say), reading around it seems that wrapping the layers in plastic for a month is the best practice here - does this mean I can not fire the oven during those weeks?

Once the render layers are on I can work on the granite entrance... from there it's merely a paint job on the dome and we are all finished I think.

[Vinz]

very pleasantly surprised at how well the local steel guy has put it all together. The added section is the lower section of the chimney and fits perfectly over the existing anchor plate. Doubled walled SS, stuffed with vermiculite, and somehow welded to the original pipe. To cover the weld connection there is a SS ring around the joint. After one heavy fire the new 2meter chimney is sucking perfectly fine and discarding smoke much better. Very happy with both the door and chimney.

Great idea to stuff the chimney walls with Vermiculite... didn't think of that and 'the cleaners' definitely threw away the remaining.. anyhow, the air in between insulates pretty well, but still the chimney sides is one of the hottest parts of the whole build.
I had a double walled, square base, stainless steel chimney welded. together with a curved mount that fits the arch the welder charged 3000THB. Plus a pizza.

[danhem]

I set some tile on my chimney and did some searching in the forum. Concluded that home brew is not the way to go. A 'flexible' construction adhesive or flexible mortar is the way to go.

Aparently a product called Monoflex is the material of choice. Available in Oz an NZ but not North America (good for you maybe).
I ended up using an 'elastic' adhesive specifically for masonry made by Quickcrete. Applied from a tube from a caulk gun.

Here's what the giant brain says about Monoflex: "A premium, water-resistant, flexible, rubber-based, fast-setting, cementitious adhesive for bonding ceramic and stone tiles to porous and non-porous surfaces subject to vibration and thermal movement."

A David S. post: https://community.fornobravo.com/for...723#post419723

Hi Mongo,

Thanks for this and apologies for not getting back to you. It does look like there is a similar product here in Thailand that will work as described by yourself and DavidS.

Thanks again.

[Mongo]

I’m looking to fit a small metal plate as decoration (with the year of build etched in) just above the outer arch. The space I want to use is part of the flue gallery brick formation and does get quite hot during a fire.

im initially thinking of using copper/brass for aesthetic purposes, mortared in place with home brew, but wonder whether the heat will cause the metal to expand and thereby crack the mortar?

I set some tile on my chimney and did some searching in the forum. Concluded that home brew is not the way to go. A 'flexible' construction adhesive or flexible mortar is the way to go.

Aparently a product called Monoflex is the material of choice. Available in Oz an NZ but not North America (good for you maybe).
I ended up using an 'elastic' adhesive specifically for masonry made by Quickcrete. Applied from a tube from a caulk gun.

Here's what the giant brain says about Monoflex: "A premium, water-resistant, flexible, rubber-based, fast-setting, cementitious adhesive for bonding ceramic and stone tiles to porous and non-porous surfaces subject to vibration and thermal movement."

A David S. post: https://community.fornobravo.com/for...723#post419723

[danhem]

I’m looking to fit a small metal plate as decoration (with the year of build etched in) just above the outer arch. The space I want to use is part of the flue gallery brick formation and does get quite hot during a fire.

im initially thinking of using copper/brass for aesthetic purposes, mortared in place with home brew, but wonder whether the heat will cause the metal to expand and thereby crack the mortar?

[danhem]

Things moving ahead nicely here, v-crete layers complete and dry, and materials finally in place to begin the rendering. I went with David S advice and purchased AR fibres, they took a while to arrive.

In the meantime I now have a door and have extended the chimney pipe. The door was custom made by a local metals works and was based on a cardboard prototype I made up. I have had to trim the top edge of the outer door as it was catching slightly on the arch bricks but apart from that the fit is very snug and the door will definitely serve its purpose. The design has been copied from many here on the forum - a cavity filled with ceramic fibre board. I'll fit some wooden handles at some point. I didn't have the energy to search and wait for a temp gauge online so skipped this part. It's a plain door but it insulates well and will be fine for my cooking needs.

The chimney - I made a pretty big error when ordered the chimney as it was way too short. Whilst the draw was pretty good, I have a building roof too close to the smoke outlet, which caused smoke to gather under the roof overhang and circulate around the oven area. Not so bad once the fire got going but not very nice. So I extended the pipe by 60cm and have very pleasantly surprised at how well the local steel guy has put it all together. The added section is the lower section of the chimney and fits perfectly over the existing anchor plate. Doubled walled SS, stuffed with vermiculite, and somehow welded to the original pipe. To cover the weld connection there is a SS ring around the joint. After one heavy fire the new 2meter chimney is sucking perfectly fine and discarding smoke much better. Very happy with both the door and chimney.

We have now employed a contractor to cover the oven, work surface and seating areas with a lovely wooded framed structure. The oven will be completely protected by the weather elements with a roof and the seating areas will enjoy shading from the sun. Pretty excited by the prospect of a completed project that will fast become the favorite and most used part of our house.

[danhem]

Yes, I get mine in 20kg bags and they’re not cheap. But it’s way faster than covering the dome in chicken wire. I used to cut the chicken wire into bits about 30 x20 cm and place them, overlapping as you go, rendering the outer shell. This may be a better method for you than going the random fibres route.

Thanks David, you’ve been a great help in these latter stages of my build.

I’ll bite the bullet and get the right tools for the job. Not sure how much of the fiber I’ll use but I guess I’ll find a use for it further down the line.

[david s]

Yes, I get mine in 20kg bags and they’re not cheap. But it’s way faster than covering the dome in chicken wire. I used to cut the chicken wire into bits about 30 x20 cm and place them, overlapping as you go, rendering the outer shell. This may be a better method for you than going the random fibres route.

[danhem]

Hi Danny,
most commercial renders have some waterproofing added which produces some resistance to water absorption at the same time as leaving it breathable. You can tell this by the difficulty in getting water to mix into the product initially. If you make your own mix it won’t have that property, but if you want to make it waterproof you can do that over the top later or leave it porous if it’s under a weatherproof roof.
4:1:1 sand, lime, cement is a pretty good mix and the lime imparts some elasticity as well as some crack self healing.
Random mixed fibres are a much easier way to reinforce the layer than chicken wire, but more expensive. The time saved in labour is well worth it IMO. You can use the nylon fibres, but I find the 19mm AR glass fibres better and easier to work with than the nylon ones which are longer thicker and stiffer. This means you have to pull them out every so often in a thin layer.

Thanks David, I’ll go the commercially purchased route in that case.

Regarding the AR fibers - is this a necessary step? I was thinking to render directly over the vcrete layer but you have mentioned a lot reinforce the render layers?

AR fibers seem to come in 20kg bags here and as you mentioned are quite expensive. Do you have a rough idea of how much AR Fibre I would likely use?