36" Pompeii in Indiana, US

[GreenViews]

I continue to enjoy progressing on my oven and patio project. Have many additions since last post and have enjoyed many pizza nights with friends and baking days the following day or two. I still have lots of details to finish hopefully this year: Soffit & facia, slate roofing, p-crete back of dome render (with vent), aluminum, insulated hinged half doors, and stone detail around opening to name a few
If I were to list some of the things I enjoyed the most about this project so far, the list would be very long, but I'll try to name just a few below.

• designing my own unique build (with tonnes of invaluable advice from everyone here) was a joy
• making my chimney opening larger than first planned and the flue area large, was a good choice as I rarely get even start of fire smoke roll out and this will keep my exterior looking good
• I love that I was able to use found materials and materials with other sentimental value like the river stone that I collected with may father. Gives it much more meaning than any extra work put into it
• Having a larger table with very ample dry storage underneath is pretty great
• A sink and prep table which drains when sprayed down, lights and outlets and other creature comforts in this space is nice

Thank you all for your help and encouragement!!!! happy oven-ing!

[GreenViews]

Made pizza last night followed by some whole wheat bread. My temp was over 850F in oven. After dome cleared, I found one actual cracked brick in oven, 4th course to right of flame in video. I no longer fear for my oven. It is a tank. It seems that was a weak spot because 3 of 4 courses had brick joints line up. Not a big deal. Temp this morning in the oven was 570 at dome, 530 at floor and my highest yet: 460F in my thermowell below both heat bulk floor layers. I don't know exact placement as I put it in after build was done, so time will tell me top temp in that thermowell. I will now give my oven a couple days rest and finish perlite concrete layer. Still a few areas with less than desirable insulation low on the dome, so this will help. If I have time I'll work on roof and chimney also. p.s. a learning curve to make great pizza, but the dough recipe given in forum is really good! And so much good info around here that it went quite well first time.

[GreenViews]

Thanks, that settles it. I was going to p-crete outside the clay to insulate, but so much less work to just lay up brick and I'm safer. Outside advice from a relative who studied and built fireplaces told me that if my chimney doesn't draft well being too large, I could just make the opening at the top smaller, so I'm going ahead with a larger and rectangular chimney, done up with firebrick! Will give me an opportunity to play with making my own homebrew 3:1:1:1 mix which I haven't used yet because I bought from the store.

Also: Soooo much easier to control temp with charcoal briquettes!!!! Goodness. Future builders: do that!!!! My goal today: keep it about 350 at top of dome: To do this, I've been alternating between briquettes only and throwing a little wood and/or paper on top for a bit of flame as the charcoal alone has been about 300F for me. Also, why waste the heat, lol... put a roast in there with it to slow cook.

[UtahBeehiver]

Clay liners need insulation on the or the thermal differential will crack them. David S has a video showing this, it in on the blog somewhere.

[GreenViews]

Thanks Russell. Yeah, I was advised. I just failed, lol.

Flue / Chimney Question: I still have time to modify my plans on my chimney. I was planning on using dual 4" clay liners, but the area calculates just under the surface area of a single 6" pipe (25 vs 28 sq inches). Also my understanding of fluid/air dynamics is that they are slowed by surface area and dual 4" pipes would have higher surface area than a single 6" pipe even if square inches was exactly equal. I thought maybe my over-sized flue entry area would make up for this. However, with my first fire yesterday (without any height, so not sure how much that makes difference with draw/draft) I had smoke spilling out beyond my flue to the front of my oven. When the fire was a good flame, nothing spilled out the front, but when everything was smokey and not lit well, that's when stuff spilled out the front. The way I see it I could:

1. Keep with my plan of dual - 4" clay lined chimney stack which has slightly lower area then recommended and probably more drag from greater surface area on sides vs a single 6"
2. Hollow out between the 2 4" holes, eliminate the clay pipes and craft a rectangular chimney out of my ample supply of firebrick. I'm leaning in this direction so I don't get smoke stains up the front of my oven. Is there such a thing as too large a chimney? I can cap ans screen it either way. laying with firebrick may actually be easier to be honest.

Thoughts?

[UtahBeehiver]

Most every oven has cracks some where. If someone says there build has none then they need to go into politics. None of the pics I see of cracks are major, just consider them beauty marks. As I have preached many times, one extra log on the fire can really spike the temp.

[GreenViews]

Ricky and Mongo, (and others who gave me earlier instruction which I failed to heed though I tried)

Thank you! I saw your posts after half the day was done and I let my fire mostly die out as I was running 500F at the top of the dome and 250 to 350 down lower on the dome. You may have saved me from doing further damage to my oven.

The Problem: Oops. Note to future builders... Yes use charcoal as others recommend.... unless you are a better fire maker than I (and I'm not a novice) a wood fire is really hard to keep going that small in your confined oven. I alternated between a small fan at an angle in the entrance and no fan, depending on how much smoldering or burning was happening at the moment.

The Not Perfect News: I did early on in the day see a couple mortar joints near the base of the dome drop a little mortar resulting in a at very deepest 1/4" deep groove in the mortar joint. (I probed it this morning with the tip of a trowel). This morning I peeled back the outside and did not see anything visible on the outside, so this seems to not be a crack as much as mortar failure from heat shock. I just went out and checked again and I have a small mortar joint crack in the inner arch as well. I will later go back and tuck point these joint areas, so it seems no permanent harm, but I overestimated my ability to control the fire. I'm glad I had the 2 days of 6 hour food heater curing and a couple weeks of sitting before this. Probably helped keep damage to a minimum. Nothing to do now but move forward... but with charcoal today, lol... goodness.

Refractory Mortar Note: The Heat Stop 50 mortar held up better under heat shock than the Acona Medium Duty Refractory mortar did. All my issues happened in areas where I used the Acona product and the higher temp areas at top of dome where I had switched to Heat Stop didn't show any problems.

The Good News: This morning without an insulated door, my top of dome temp is 270F and floor is 220F, so my oven held this temp overnight, which I suppose is also representative that I added heat too fast, but the good part is my insulation is doing its job . Also good news is none of my problems are structural issues or issues I cannot fix (even if imperfectly) later.

Humbled by my lack of fire control, but determined to take it all in stride and be happy.
Tom

[GreenViews]

Greg, Yeah I used a 50:50 mix of fireclay and sand (I used fine silica sand, but others have used other). I think any good clay product is fine. To keep from relying on the clay/sand layer to hold up the brick if the difference is more significant, one idea would be to not vary the sand/clay layer much, but rather bring the second and third course into level by adding a little to each of your joints on the low side of the dome or alternately cutting your bricks a little thicker on the low side until you are nice and level. That would put your correction in the stable material rather than the float material. But I don't have enough experience to know if you would have problems and I'm sure it would depend on the amount of correction you are talking about. Regards! Tom

[P3 Stoaker]

G'day Tom,
Hope the 'firing' is going well.
I noted you used fire clay under the first course. Was it 50% sand?
My floor is fairly level but a couple of the edge cut bricks are a little lower and the dome first course will likely sit back a little kicking the front edge up. So I plan to start without fire clay at the highest point and use the clay to keep the course level.
When purchasing the fire clay the salesman knew it was for a pizza oven but no detail. He advised me it wouldn't set and would wash away with rain or water. Whilst it shouldn't get wet and I don't plan on hosing it, I do wonder about its weight bearing strength? I know the advice is 50/50 fire clay and sand but I can't imagine sand increasing it's strength. So I'm now wondering if there is a difference in the product here in Australia compared to USA, I know other products are significantly different to the point I'm cautious and like to avoid a disaster.
What did you use and what ratio? I might mix up a little for a test.
Regard

[Chach]

Small fires go very slow. Yes the fires can get big very fast just don't put a ton of fuel in. Keep an eye on it you can always use a small metal shovel to take some wood out while its lit to make the fire smaller if it gets to big or spread it out to even out the flames.

Ricky

[Mongo]

I think a 300f curing fire is shot on the dome above the fire.
All those flames even though they come from what looks like small twigs are producing a very high temperature spike. Even crumpled newspaper can produce a crazy amount of heat for a very short time.

I was very paranoid during my cure and took some notes and photos. I can offer you what I did and tell you that as far as I know, there are no cracks in my dome. At least none that I can see. Honestly I haven't really looked that hard.

Don't use the wood you are using for your initial curing fires, and don't spread them out like in our photo until later on in your cure. Keep a nice small compact fire.
When I first added a 'normal' stick of firewood to a fire it flamed up and created like a 150 degree spike. I freaked out and removed it with tongs and the temp came down almost immediately.

My first fire was a small pile of charcoal and a tiny piece of hardwood kindling.
I continued to use charcoal but just added more kindling, and still use charcoal to start my fires. Works great.
Think I did at least 6 fires before the inside of my dome even turned black, and didn't 'clear' the dome until about my 10th fire

These are my rough notes and a few pics.
I took temps at the apex of the dome and at about 3 bricks up from the floor. Where I list 3 temps, they are apex, 3 bricks down, 3 bricks up.
Day Temps
1 125 / 80.
2 150 / 80
3 190 / 100
4 250
5 300 / 180
6 400+- / 210 / 200
7 530 / 480 / 350
Stopped taking notes at this point.

Photos are my day 1 and day 6 curing fires.
Interesting that on day 6 there was what looked like a lacquer coating on the dome but no black soot yet.

Summary: use charcoal, keep you fires small and compact and control your flames.

[GreenViews]

HELP, what does 300 F curing fire mean? Fire pictured was waaay too hot. I couldn't get the darned thing to stay lit at first, then woosh, takes off and I'm 500F everywhere for a while. Sooo... is 300F temp mid-height of oven? on Floor? This I can get close to, but even with a tiny fire (I've been learning to regulate it better through the few hours since I started) the temp at the top of the dome is always 500F or so. While having an active fire even with a few very small twigs burning, I've not gotten the top of the dome below that temp. Any thoughts on what a 300F curing fire means????

[P3 Stoaker]

G'day Tom,
WOW, impressive progress so quickly. Was only a few weeks ago we were at the same stage. I see you have reasons though, getting some quality time with your daughter.
Initially I had hoped to complete my oven for my Son's 18, but that was last Friday and that ship sailed quite a while ago.
Regards

[GreenViews]

Work yesterday:

• Glued aluminum edge to bottom front of oven entrance (will have entrance very slightly lower, so this is to protect the front of oven floor (firebrick splits)
• Tucked and glued fiber rope into crack between angle iron for door and inner arch
• Insulated with fiber blanket: most areas of oven with 3 in blanket, some lower ares have only 2 in and 4 places along first half soldier course have none, so I can directly support / buttress with 5:1 perlcrete for structural insurance. I added wire mesh only around the base of the fiber blanket. Just realized I need to cut this away from the areas with no fiber blanket to keep it from being a heat sync carrying heat away from the oven along mesh to outside the fiber blanket. I will cover all this with p-crete.
• Cemented in the flue and mantle areas. I decided on a mantle directly above the entrance which curves out to make it more appealing and make up for the lack of arch in the front of the entrance areas since I decided to go with angle iron supports for chimney and flue.
• Lit 2 more 6 hour food warming candles which seem to create a top temperature of around 200 F and loosely sealed the doorway with sheet metal

[GreenViews]

Placed the flue, base to chimney and mantle last night. Since it is outside the main oven, I decided to cement it in without delaying the drying process too much. I also insulated oven, pics to follow.