36" Pompeii Dome - Thailand

[danhem]

Finally made the move to construct a 36" dome oven. Selecting the location and getting the foundations laid has been a challenge and I only expect it to get steeper over the coming weeks.

We decided to make use of some space at the back of our house, over looking pineapple fields and mountains as the sun goes down. The thought of cooking pizzas in the surroundings is motivation enough, whilst adding a whole new dimension to what is essentially wasted space at the back of the house.

First job - Concrete in a 40ft x 1ft space bringing it level with the balcony to act as a platform for an outdoor kitchen and seating area. A big job for a one man band so employed a team of contractors for this part.

Second job - The first day proper as I took delivery of the Stand materials and began to lay a rough draft of the Stand.

A few pics attached in the link below - probably the first instalment of many. Not sure I'd have the confidence to attempt this without the knowledge backed up on this forum. I hope in time my project will be complete.


**edit - ignore images link below, doesn't seem to work so will use the Forum image hosting service.

[UtahBeehiver]

Great start, there was another Thailand build done recently so you can check that thread for info on oven materials and such.

[danhem]

Thanks UtahBeehiver, I found TxGR and followed his post, seems we have sourced materials from the same place (perhaps only place in Thailand).

I had a couple of challenging days fixing up my stand. The block dimensions as listed were not available here so I had to cut a number of blocks to fit the recommended stand dimensions of 70"x63". In the end my stand measures at 70"x67". The blocks I have are 15" x 5.5" x 7". After the initially laying the first course out, the stand width was short of the recommended 63". To avoid a great deal of hassle cutting up lots of block I decided to make the stand width slightly wider (67"), mindful of the space required for the oven itself - more space being better than less space.

I wonder with the extra stand width I can increase the oven diameter by an inch or two, or whether such small measurements are irrelevant?

Another problem caused by the type of block I have is that lining up the holes for rebar and cement to fit was tricky. After cutting and layering the four courses, I dismantled the stand ready to set it with concrete and rebar. To make sure I had the holes lined up properly, I set the first two courses, and filled the holes with cement and rebar. For the final two courses it was a case of fitting the brick holes through the protruding rebar and filling with cement. The whole process from taking delivery of materials to where I am now has taken 12 man hours over 2 days. Not sure I'll ever make it in the building industry but I certainly appreciate the work of those who have.

Since the manual mixing of cement and moving of building bricks was a first in my 40 years of life, my back is sore this morning so I'm taking a break before adding a finish to the inside of the stand. I figured that leaving the brick exposed would be a point of frustration in the future and its much easier to finish it now before the hearth covers the top.

All in all I realize that this will be slow and heavy going but highly committed to getting it finished in the shortest time. Whilst the stand may not be a perfect structure, it's pretty solid and should withstand whatever will sit on top.

[UtahBeehiver]

You can make the oven any diameter that works for you. The only factor is the inner arch height which should be around 63-65% of the dome height (or dome radius). The extra base dimension is fine, better to be long than short. You need to factor in access to you build on the back side by the stucco wall. Too close will make if difficult to work around.

[danhem]

UtahBeehiver - I’ve been through your build post and highly envious of the outcome. Awesome.

You started the build thread offering the forum documentation for those who are interested. I am certainly interested if the offer still stands?

I take delivery of my firebricks and insulation materials tomorrow so things are about to get real here!

thanks,

Danny.

[danhem]

Making progress, slowly but surely. My neighbour and friend who has a number of years being a handy man under his belt foresaw an issue with us laying the hearth and then removing the plywood and supporting stands. We both have back issues and sliding into the stand cavity on hands and knees to remove the plywood and stand supports was a worry for us both.

As a master stroke, we purchased some reinforced concrete slabs (total cost = $35 delivered) that are laid across the stand to act as hearth support and to avoid the plywood base to set the concrete pour. The concrete slabs are 2" deep so we will still position rebar and a further 2" of concrete on top. The slabs didn't fit flush across the stand but that was sorted with a little bit of work with the grinder.

It's taken a day or two longer to get where I currently am but I took delivery of my fire bricks and insulation materials today so hope that by this weekend I'll be starting on the oven build itself!

[UtahBeehiver]

Most of the documentation is in the form of the photo album but I do have some offline info. It just depends on what you want. Shoot me a question and I will try and answer, there are a lot of builders on this site who have great advice as well. I am not a big fan of the YouTube videos out there, some info is good and other info is downright bad. So now is the time to be thinking about an indispensable tool, AKA IT, it is well worth the time and effort to build one, make sure ii is adjustable.

[Yokosuka dweller]

Hej, Nice you found pre-made concrete plates. Makes the job of pouring hearth stand a lot easier. I guess you are now prepping for another additional layer of concrete on top of the plates? You can consider to use your angle grinder to grind some grooves into the existing plates and then remove the dust (nothing sticks to dust). Then 'paint' the plates either with a bonding agent or a mix of portland and water (consistency of paint). Pre-wet the plates and then brush the 'paint on' and then you must be quick to pour the new concrete on top before the 'paint' dries. This is to increase the bond between existing and new concrete. I did this on my own hearth stand, because I poured it over several weeks. And even with the bonding agent, there is one corner where the bond didn't work. So just a heads up.

Other point, may not be relevant but consider: your concrete form looks fine, but it looks like you are using very few screws. I cannot really see how deep the additional pour will be, but if its more than 1-2cm the new pour of concrete weight will push the form our a bit at the top, so your concrete will not be totally plumb. Perhaps not a big deal,but you can fix this by wrapping a solid cargo/belt strap around the form's circumference to avoid it from moving due to concrete pressure.

edit: I can see you're pouring up against the retaining wall of your garden. Good idea, but then the 'belt' idea won't work probably. In any case, you may then have to reinforce the sides of the form somehow to avoid it from bulging. Maybe put some stakes into the ground that can ensure the form stays put while the concrete sets.

Cheers,

[danhem]

Most of the documentation is in the form of the photo album but I do have some offline info. It just depends on what you want. Shoot me a question and I will try and answer, there are a lot of builders on this site who have great advice as well. I am not a big fan of the YouTube videos out there, some info is good and other info is downright bad. So now is the time to be thinking about an indispensable tool, AKA IT, it is well worth the time and effort to build one, make sure ii is adjustable.

Many thanks, I was at the hardware store yesterday to pick up some IT supplies but the damn thing is closed until 12th April due to the CoronaVirus measures. This will put me back a few weeks now as I was also there to buy a chop saw for the brick cutting, Will see what I get get online.

As far a questions go...there will likely be many as time passes on. I was just curious to see if you had documented your oven plans with dimensions etc.

[danhem]

Hej, Nice you found pre-made concrete plates. Makes the job of pouring hearth stand a lot easier. I guess you are now prepping for another additional layer of concrete on top of the plates? You can consider to use your angle grinder to grind some grooves into the existing plates and then remove the dust (nothing sticks to dust). Then 'paint' the plates either with a bonding agent or a mix of portland and water (consistency of paint). Pre-wet the plates and then brush the 'paint on' and then you must be quick to pour the new concrete on top before the 'paint' dries. This is to increase the bond between existing and new concrete. I did this on my own hearth stand, because I poured it over several weeks. And even with the bonding agent, there is one corner where the bond didn't work. So just a heads up.

Other point, may not be relevant but consider: your concrete form looks fine, but it looks like you are using very few screws. I cannot really see how deep the additional pour will be, but if its more than 1-2cm the new pour of concrete weight will push the form our a bit at the top, so your concrete will not be totally plumb. Perhaps not a big deal,but you can fix this by wrapping a solid cargo/belt strap around the form's circumference to avoid it from moving due to concrete pressure.

edit: I can see you're pouring up against the retaining wall of your garden. Good idea, but then the 'belt' idea won't work probably. In any case, you may then have to reinforce the sides of the form somehow to avoid it from bulging. Maybe put some stakes into the ground that can ensure the form stays put while the concrete sets.

Cheers,

Het thanks for your message, I'll be sure to follow your suggestions on preping the slabs before pouring the next layer of concrete. The side forms are firmly screwed in, but you are right about the front - I'll prop some wood up against to prevent the bulge.

PS - We were supposed to be in Japan right now on holiday but had to cancel due to travel restrictions for the Corona virus. We will try again next March. At leat I'm able to press on with my oven.

[Yokosuka dweller]

Yes, it is a strange reality at the moment, a wake up call that our destructive ways on this planet are hitting limits...Although Japan has been floating much in its own world, seemingly they 'flatten the infection curve' here. But probably it was an effort to keep the olympics on track by testing very few people. Now that that's solidly off track anyway, can expect to see infection number rise also here. So, wherever we are, it is no doubt the right time to just hunker down, stay put, and get the various garden projects advanced.

I guess you are in Thailand? They've also closed borders now. If you're there then it's probably not an issue at this moment, but travel is difficult. I lived in Thailand for several years myself (1998-2001 and 2006-2010, and 2013-2015). I liked many aspects of it, got tired of the incessant heat, pollution (Bkk), and the increasing (but understandable?) fatigue among the locals to the 'farang'. Still many great memories some of which better to be shared over beers. Anyway, I am side tracking your thread here, so sorry about that. Good luck with the rest of the hearth pour. I will check back in here again later to see you progressing with the build.

Enjoy!

[danhem]

I am trying to work out the best brick cutting tool to buy and use. Seems that a Chop Saw (pic. 1) would be the most versatile option for cutting precise angles. Problem here in Thailand is that getting a 10" masonry blade to replace the wood blade the machine comes with seems to be an impossible task. I know the 10" blades are available on Amazon US/UK but that seems like a risk to take on delivery under the current COVID climate.

The best option offered by the sales staff here can be seen in pic. 2 (apologies, not sure of the correct terminology of this saw). The blade is 10" and will slice through the brick without any problems...so I'm assured. Seems here that this machine would not facilitate angled cuts as required on the bricks. Is the where the 'Jig' comes into play?

I have come across a 'Jig' thread on here but can not for the life of me find it now. I am trying to make the cutting process as easy and as accurate as possible.

Any thoughts on which way to proceed on the machine purchase?

[david s]

It is possible, but bear in mind that dry cutting of bricks produces an enormous amount of dust. This dust is highly dangerous to inhale because the very fine particles of fired brick are really sharp and can easily damage the silia in your lungs which can result in permanent lung damage, for either you or your neighbours. A normal dust mask is not adequate, you need a decent respirator. In addition this fine dust gets into the air intake in the motor of the drop saw. It is designed to cut metal plastic or wood, not brick or refractory material. You can set up a water drip feed onto the blade to reduce the dust, but also remember that you then increase the risk of electrical shock. Water feed electrical equipment normally have a sensitive and heavy duty electrical safety cut out.

[JRPizza]

If you search through the forums you can see what others have done that did not have access to a proper brick/tile saw. I seem to remember hearing of folks soaking bricks and cutting them wet to try to reduce the amount of hazardous particulates that david s describes above, but after using my brick saw I'd be very hesitant to try to cut a brick with a chop saw. Having water feed and the slow rotational speeds of a proper tool can allow you to cut bevels etc on small pieces of brick without having to worry about losing a finger. I bought my saw with the intent to resell it after my oven was done, but have held on to it to cut the occasional brick or piece of tile around the house.

[UtahBeehiver]

TxGr bought a wet bridge saw at a store in Thailand so check his post out. A wet saw is your safest and best bet.