"Pompeii" corner WFBO project in Loei, Thailand

[danhem]

Hi,

Just wondering if you are still building and continuing with the BST mortar. Laid my first bricks today and I’m sure that the mortar isn’t going to bond properly.

Looking for alternatives and possible suggestions of suppliers in Thailand?

Thanks,

danny.

[danhem]

You are wasting your money buying a mortar that contains high temperature aggregates that your oven does not require. You also won’t get it to the temperate required for it to sinter. The homebrew is a far better mortar for ovens. As the data shows the high duty bricks are way harder and will be a bitch to cut. Medium or low duty are more suitable for the dome. Medium duty for the floor.

Hi David,

I have used the same mortar as discussed here and half way through my 9th course the mortar has seemed to set really quite solid. However I remain nervous about the curing fires and hope the whole thing doesn’t come tumbling down after heat has been applied.

I was wondering if you knew of a method/product to clean the mortar off the inner oven bricks. Even though I’ve tried, I’ve had a real difficulty cleaning the mortar off and it could look a little neater in there.

i did read of some kind of acid mixed with water (1:10 ratio). Knowing the properties of the wet refractory mortar, do you know of the same acid mix would be suitable?

[TxGR]

danhem I am still using the BST mortar. Unfortunately, I had to return to work and left Thailand in late March. In late February/early March, my better half insisted I hire help. This did speed things along, but I quickly lost control over some of the quality aspects important to me. Their construction was solid, but no matter how many times I insisted the inside was the finished side and I wanted the most critical alignment there, they put more effort into finished the outside with the expectation it would all be covered up later anyway.

With respect to the earlier advice I received, if they had read, they might have noticed 1) I bought the lower grade of refractory brick, 2) I already bought the brick and mortar. Telling somebody they are "wasting money" by buying product X after they already made the purchase isn't advice, at least not to the person on the receiving end. In any case, as I explained, choices in Thailand are limited and communication difficulties combined with cultural differences make finding other sources very challenging. Most Thais, if you don't want what they have in stock are not going to make the effort to tell you where you can get something else or even if they can order it. I tried to buy flyash or at least cement with high flyash content and even though Thailand produces the stuff in massive quantities, there is just no place to buy it retail. In some cases, I found ordering online (within Thailand on Lazada or Shoppee) was much more expensive, but at least I could find what I needed.

Cutting the SK30 bricks was not an issue. I seriously doubt I could have acquired what I needed for homebrew mortar. Beyond that, I already had an extensive project on my hand stretching my abilities (and the patience of my better half). Adding custom made mortar presented would present a whole new series of challenges and difficulties. This mortar has been successfully used by others in Thailand.

I'll add some pics of where the WFBO stands now. I am trying to come up with finishing notes to relay to the new workers.

In pic above, you can see the arch wasn't cemented in yet, but the coursework was coming along. The angle of each layer required wedges due to properties of the mortar (narrow gaps only).


This is a few courses later, after the workers started doing the cementing. They also did the arch. I wasn't very happy with the arch because it droops in the middle. This should all be hidden, but mortar here is holding fine.


This was close to where I left it. I really screwed up on the inner arch. I was using the IT to arch cut the inside angles as I understood from the other posts. The work was even pretty nice and contoured, but to the wrong way. I beveled the outside of the arch, but to the radius from the center of the arch. That made filling in from the courses of the dome messy and requiring lots of custom cuts or wedges. The IT should have remained straight/level so the bricks on the outer side of the arch would be much taller/thicker and the bricks on center of the arch much shorter. I didn't realize this until we tried to put the next course apart. In the pic below (from today), you can see how the courses of brick drop or droop toward the archway. This is where communicating with the workers really failed. Supposedly they had another job, but they just never returned. I tried to compensate with wedges and custom cuts. It looks horrible, and like the cut at the top of the soldier brick, properly cutting, measuring, and understanding what I was doing would have saved me scores of hours trying to fix it.

This is where we stand today. The outer arch is just sitting there for the moment. They'll take it down and finish the dome, and then cement it back in place.

[TxGR]

Here is a closer pic of the madness game of masonry tetris I had to play to get past the arch. This was from right before I left I believe.

[danhem]

Good to hear back from you and that the project is somewhat on track (your pics did not come through in the post). Frustrating here dealing with the locals who know best under ALL circumstances. Equally frustrating hunting down materials.

danhem I seriously doubt I could have acquired what I needed for homebrew mortar. Adding custom made mortar presented would present a whole new series of challenges and difficulties. This mortar has been successfully used by others in Thailand.

With the help of a Thai based forum member (Sven SvR), I managed to finish my vent and flue area with the homebrew. I was/am very worried about how the refractory will hold up as Sven has been been through 2 ovens where this mortar failed him after a year or so. He has sourced the hydrated lime and been kind enough to supply a 25kg bag. I'd be happy to send you a sample if you would like to try it out.

I actually ripped down my outer arch built with refractory and rebuilt with the homebrew. Its much easier to work with. Also finished off the vent and flue area with the home brew and am very happy with how it has turned out. Time will tell whether the dome will hold up. Ripping down the outer arch was a bit of a struggle - the mortar was pretty well set, which has filled me with a little bit more confidence that the dome will hold up.

Onto my curing fires now but with the weather being as it is another challenge is presented - my under floor insulation has soaked up a lot of moisture and the inside oven feels damp. I cover the oven completely when the rains come and uncover as soon as they pass. Problem is that if covered for a long time a lot of condensation builds up. I will continue to fight the rains for a while but I have a feeling that it won't be until later in the year that I will get the oven dry enough to use for its intended purpose.

If you want a lime sample, please ping me a private message with your address and I'll get it sent to you.

Cheers.

[TxGR]

I appreciate the offer. I am not in Thailand right now, and probably won't return this year. They (I don't know who 'they' are) are starting work again today. I have no idea what they are going do or if they will follow the instructions with pics I laid out for them. This will go through at least two people before it gets to the actual worker, so who knows what they will be told. I might change my mind later and ask for where you sourced your materials, but as of right now, I can't imagine trying to explain it to them.

Sven and I exchanged some notes or emails. He told me about his issues, but there was another person who successfully built an oven using the BST mortar and his oven lasted. I don't understand how Sven's oven collapsed. They are self-supporting structures. Once complete, even if the mortar degraded, I would expect them to remain standing until something hit the bricks or jarred them. I guess the expansion and contractions of heating caused enough motion to result in collapse? There are ovens in Italy hundreds of years old and I am sure their mortar was pretty iffy by modern standards. In Poland, the brickwork is excellent, but the older mortar is garbage (maybe they were using beach sand which included salt?). The rendering doesn't last very long and I'd say ~50% of the mortar in many older buildings is significantly decayed - but they're still standing. Of course, I didn't lean on them to test their strength. Sven was also focused on water damage and seemed determined to put his oven under a roof. Based on other conversations I had, I will be coating my oven in a high temperature epoxy sealant/paint.

I think he's correct about our greatest enemy in Thailand being the elements.

In the places where I've had to remove something or try to clean a brick, I've found the set mortar almost impossible to chip away. At this point, I am much more concerned about the building process (who is doing the work and instructions) than I am about the materials.

My base became quite wet too. All I can do is drive it out with the curing fires, if we ever get to that stage.

I tried reloading the pics. I hope that works.

Cheers,

[TxGR]

Trying to supervise workers in doing something they've never done before, when you share no common language, is challenging to say the least. Then trying to do it through a third person from 5000 miles away leads to mis-communication and fundamental errors.

I had to leave Thailand at the end of March. Recently, the workers returned to finish the dome. I explained to them what I was trying to do when I was there. I printed out numerous pictures from dome projects showing them how to do it. I even wrote up a big instruction document in simple terms, with lots of pictures, with the plan my family there would translate. Instead, I ended up with this:


The 'hump' is where they reached the end and just mortared over some bricks (more below). I cannot fathom how they ran out of brick, there was way more than enough. All I can think of is they discarded the several courses of brick I already cut. Anyway, since they didn't have sufficient brick to build up the chimney base, they just cut into the arch...ugh. Worse, I had decided against using the outer exhaust pipe, they used it anyway and cut into the outer arch accordingly.


I think the last four courses are their work. It's like they just reached a certain point and gave up. The last couple of courses they just stoped used the IT. You can kind of see it starts to curve up, not down. I had the floor covered with plastic. I carefully set aside the center floor brick. They used the center brick for something else. Fortunately, there was at least one brick in reasonably good shape and complete we could use. Unfortunately, I think they swept debris into the whole, or it fell in, when they removed the IT. To me it looks a little proud, but that could just be an illusion because all the other bricks are discolored.


This is the real issue. I am not even sure what is holding those bricks up. I am not happy about this, but when I "gently" suggested having this part redone I was told that was no longer an option. Hmmm...mmkay. Despite all the expenses into something that is not right, I think I will have to live with this until it fails. They haven't started finishing the outside. Once that is done, refinishing this part become totally impractical.

For obvious reasons, I don't consider this project particularly successful. I learned a lot. When I am actually living in a place where I can build one, I will probably try again (in Texas) and there are a number of things I will do differently, especially with respect to the mortar and brick cutting. Most importantly, I will do the work myself or directly supervise whoever is doing the work.

I do appreciate all the help and suggestions. I will probably post additional pics once they put on exterior finish. I will be honest enough to post pics if it falls apart.

[Chach]

Wow you were doing so good and it was looking real good. you can fix it still if your not happy. getting passed the arch is the hardest part. you can have that fixed in no time.

Ricky

[TxGR]

Thanks Ricky @chac. If I were there, I am sure I could fix it. Unfortunately, my powers of remote control are limited. We'll see how this works and then try again.

Right now I am looking for a source for wood. I am also going to take the advice of danhem and SvH to switch mortar. I'll try to find the recipe for homebrew and source the materials.

Unless anybody suggests otherwise, I am going to use this formula from the FB plans pdf:

•1 part Portland cement
•3 parts sand
•1 part lime
•1 part fireclay

I'd like to use cement with high flyash content as it is cementious and high temp impervious.

For "fireclay" I will use the fine powder I captured from all the firebrick cutting. I have more than a 3 gallon bucket full of the stuff. If this is a bad idea, I hope somebody tells me so.

[SvH]

TxGR if you live near or in a closed living area (moo baan) there is always someone that cut the trees away from the electricity lines. That person does sell wood. Try to buy wood of 1 year old, not fresh wood because of bugs like to eat that. Keep the wood on a dry place in the sun.

why my first dome did collapse with the standard fire proof cement... maybe the space of 1 or 2 cm between the bricks was to big but I believe that this was not the issue. Sometimes the weather conditions here are strange. Extreme winds and a lof of heavy rain and even when the dome is covered still it does get a little wet... humidity! Big thing here, some days are okay but for sure this is an issue. Mortar did crumble creating some cracks and gaps from the top and even when the dome is self supporting one stone on the top came loose... the top stones are placed as last and when it does crack on top you can imagine what happend a few months later.

see my other post where you can get your brew materials.

[danhem]

Hi TxGR,

Damn thats a shame, your early prep work was looking great, looks like the locals made a real mess of your plans. It's just another example of them knowing best. I think the other thing with these builds that unless you employ a real mason who know whats he's doing, the care and attention to detail can not be matched by anyone other than yourself.

I know from your early posts that your approach to perfection will likely result in you ripping the oven down and started from where you left off. Aesthetics aside, it remains to be seen how the oven will perform once you get back here and start to fire. Its a nervous time knowing that we haven't used the best mortar materials for the job. My oven has so far held up to a number of pretty strong fires and cooks. Besides the cracks in the wet refractory mortar that appeared in some joints, it doesn't look like things have gotten any worse so I live in hope that I will get some use of of the oven for a few years at least. I'm still not getting the heat retention results as others on the forum have recorded but I'm putting it down to it being a new oven that is currently without a door, and perhaps I need to work on my fire management skills. With all that aside, I'm sure the oven will function as I need it to and the work in progress continues with fun.

SvH has been really helpful with a number of issues, learning from his experiences. I finished my outer arch and chimney area with the home brew, lime supplied by Sven and other materials were sourced locally. I used standard kiln clay for that part as I couldn't source and powdered clay, which would be much easier to use I'm sure. I am not sure that using brick dust instead of clay is a recommended idea. I thought I had read that the properties of clay help with the expansion/contraction of joints as the oven heats and cools....might be worth asking an expert on this though.

The home brew is far easier to work with than the wet refractory. If anything, should you have to re-build, you will have peace in the knowledge that your finished oven will have been built alongside the guidelines of tried and tested methods used here on this forum.

As Sven mentioned above, humidity here can be a killer. Even a protected oven dome is likely to get damp. I will add a vent at the top of the oven allowing steam to escape should moisture work its way in. Take a look at this link here from Gulf - Vent Info. With this I plan to fire the oven fairly frequently to fight off moisture. The beauty about these ovens is that their cooking ability is so versatile and many other foods can be cooked other than pizza. Yesterday I fired it for an about an hour, let the fire burn out then cooked 4 hour roast pork belly and roast veg in there, it came out way better than what our kitchen oven has delivered in the past. The point being....I'm thinking that small frequent fires could help to protect the oven whilst making good use of the heat at the same time.

On top of that we are working on getting a roof and surrounding shelter to protect it, and of course during the really heavy monsoon we have here in Hua Hun (Sept/Oct) I will just wrap the thing up as best I can.

Regarding wood - I've asked around a number of Italian restaurants here in HH and in Bangkok what wood they are using. All are saying Mai Son (Thai Pine). Sven does have a good point on this wood, it burns through very fast and perhaps doesn't burn off as much heat as another wood would . My Mai Son supplier here also supplies the Sheraton and Centara from their wood ovens so it seems to be a viable option for me for the time being. I asked if they could get any other types of hardwood but she said this was the best for pizza ovens. 10 bht a kg for dried wood seems fine. I'd say that I use around 7kg of wood to clear the dome and for it to be ready for cooking pizza (900F dome bricks / 700F floor bricks). At this stage, one 12" log, split in half fires a great flame up and around the dome and lasts long enough to prepare and cook 4 pizzas before requiring more fuel.

Again, Sven gave some good advice on sourcing wood. As above sourcing from a local tree surgeon and the drying it sounds like a good option. My problem here is, that unlike Sven, I don't have a massive warehouse to store and dry the stuff. I'd also be a little unsure of how suitable certain types of wood be for the oven. I tried eucalyptus at first but later read that that it contained too much oil that isn;t good for these ovens. Another option Sven gave was to source wood from wooden pallet manufacturers. I'm yet to source any this way but it does look like some wooden pallet manufacturers import hardwoods for their purpose and these would be great for burning in our ovens depending on the price of course.

Wish you luck going forward.

Danny.

[danhem]

TxGR if you live near or in a closed living area (moo baan) there is always someone that cut the trees away from the electricity lines. That person does sell wood. Try to buy wood of 1 year old, not fresh wood because of bugs like to eat that. Keep the wood on a dry place in the sun.

why my first dome did collapse with the standard fire proof cement... maybe the space of 1 or 2 cm between the bricks was to big but I believe that this was not the issue. Sometimes the weather conditions here are strange. Extreme winds and a lof of heavy rain and even when the dome is covered still it does get a little wet... humidity! Big thing here, some days are okay but for sure this is an issue. Mortar did crumble creating some cracks and gaps from the top and even when the dome is self supporting one stone on the top came loose... the top stones are placed as last and when it does crack on top you can imagine what happend a few months later.

see my other post where you can get your brew materials.

Hi Sven,

On the humidity issue, as mentioned above I'm thinking that with a vent installed at the top of the dome and with frequent fires (not necessarily full blown out pizza prep fires), this may help to fight off humidity and rain moisture? I know that with the wet refractory mortar, even after it has set for a while, simply soaking a brick in water seems to turn the mortar into sand/grain that can easily be cleared off the brick. Is this what happened to your oven, it got too wet and then the mortar gave way?

Hope all is well up there where you are.

Danny.

[SvH]

TxGR

I agree with Danny... Use standard kiln clay . Easy to get on Lazada. Correct that the properties of clay help with the expansion/contraction of joints as the oven heats and cools.
I am working to get powder clay I will send you a PM.

As Danny also knows... I am planning to build my third dome and that one I will build as much as possible "indoor" in the garden. So side walls and a solid roof to protect it against the elements as much as possible. My chimney will be made from bricks not metal.

My current dome does work well but is not insulated. I had problems with the first one, as mentioned, so I did worry a lot when I built my second one. Because of my worry and knowing it would be another learning curve again I did not do all things as I wanted. This was a right choice for me and again I have learned from many "problems" and understand a lot better how to solve them for the next one. So my final dome will be perfect (I hope) and it is on the drawing table. Not sure yet if it will be a dome or a Neapolitan shape but I made a 3D drawing. Because I need to make a solid floor foundation in the garden with reinforced concrete and pillars it might take some time and I might want to wait until November so the humidity will be gone. I sourced all the ingredients and that took me a really long time. My advantage is I have some chemistry background and a network in and outside of Thailand because of my work. Spoke to people that manufacture cement in Thailand to understand it better and realized that there is not the right cement available of what we want to do...

I am more than happy to help you, as so many people on the Forum also helped me, that is why the forum is here. However, please note that I am not always active on the forum or get notifications for some reason. So I will send you a PM so you have my direct contact details.

[SvH]

danhem

Hi Danny !!
I am doing great, THX and I hope you do too.

On the humidity issue, as mentioned above I'm thinking that with a vent installed at the top of the dome and with frequent fires (not necessarily full blown out pizza prep fires), this may help to fight off humidity and rain moisture? I know that with the wet refractory mortar, even after it has set for a while, simply soaking a brick in water seems to turn the mortar into sand/grain that can easily be cleared off the brick. Is this what happened to your oven, it got too wet and then the mortar gave way?

Yes the mortar got to wet and gave away but not because of the the amount of rain only as it was covered. I will explain the setup of the dome... My dome is build against a wall so only 3 sides are open. I made a roof above my first dome that had an overlap of 1 meter. Most of the times this was okay but sometimes the wind spins and blows like crazy while a waterfall from the sky is coming down on us. (You know what I mean). So the wind did blow some rain on the dome sometimes. It became moist and wet but it should not be a problem as many domes are outdoor but because of the humidity, water was not released from bricks and mortar and the the climate we are in took control.

The type of mortar or cement people recommend us to use here for making an oven is not the type of oven we are using. We do not burn people or make cast iron. From what I understand is that inside the cement or mortar there are chemical components inside that set between 900 - 1600 degrees Celsius depending on which type you use. The first question is do we reach that temperature and if we do can we keep it up over time? People told me after my problems happened.... that if you do not keep it up over time slowly the cement will become less strong so the oven should be used actively to set the chemicals can set again and again.

I know you use your dome quite often but I did not. Specially in rainy season I was not using it at all. The weakest point for me was the top of the dome, the final few bricks you place. It started to crack and crumble there and the rest is history...

[TxGR]

SvH & danhem Thanks for the detailed responses. I have your contact info Sven and will respond to your email.

Maybe I'll use the fine brick dust in lieu of part of the sand if I can get the right kind of clay. I wish I could buy some flyash. That would probably be very good for our ovens.

I think I'll get them to coat the inside of at least the upper part of the dome with the homebrew. Then, I'll have them mix the homebrew with some crushed lava rock I bought (I think they it translates as mountain rock in Thailand) as a thin outer layer to the dome, then the ceramic fiber blanket, then a thick layer of mortar with crushed lava rock for the exterior. Then I plan to seal the whole thing with an epoxy layer after drying it out as best I can.

Gulf vent idea is interesting and might be an important addition if I epoxy everything else. His dome looks so nice, even, professional...sigh.

I am optimistic I'll get some use out of this oven for at least a few years. We plan on cooking many things with it, including a lot of bread. There was a channel on YouTube where this Brit living in LA did several episodes of cooking, the Wood Fired Oven Chef, you've probably already seen it. The production values are very high. Looks like he started again. My favorite episode is easily when he does the thick steak...boy, wouldn't I love to do that in Thailand. https://youtu.be/Djoub57k9Vk

For my next oven in Thailand, I will buy a nice 12-14" brick wetsaw in Europe and bring it in pieces to Thailand so I can make precise, complex cuts. The design will be very similar, but I am working with my dad on detailed plans to cut all the dome bricks the same leaving only the very narrow mortar joints. He was an engineer for 50+ years and has some advanced CAD software which, if I successfully communicate my idea to him with the right dimensions, he can then give me the proper size and cuts for everything.

I can use the same plans in Texas where I will build at least one more oven. I believe I found a source of bricks in the US that is the same size. I'll still use the BST bricks. It's just their mortar that is an issue.