Wanting to build a coal fired style outdoor pizza oven

[foreplease]

How are you feeling and how is the oven coming? I hope by now you have been able to enjoy using it. Any finish photos?

[Pod4477]

How are you feeling and how is the oven coming? I hope by now you have been able to enjoy using it. Any finish photos?

Sorry!  I haven't checked here in a while.  My bad.  Feeling better, thank you!  I still need to clear some more land for a garden, so I'll have to cover up from the poison ivy around haha.  The oven is very close to done now.  I finished the first layer of stucco and need to do the final layer next week.  I'll post some pics here tomorrow from my phone.  I made two pizzas today for a Halloween party and they both came out good! The second one lacked the heat on the bottom from the oven floor, as it wasn't quite hot enough after cooking the first pizza, but I'm learning, and I could have just moved the fire back over before making the second pizza. How are you doing?

[foreplease]

Doing well. Glad you are healing up and enjoying your oven.

[Pod4477]

Doing well. Glad you are healing up and enjoying your oven.

Awesome! Glad to hear it, and thank you.  I have to focus again on the dough side of things.  I also need to learn how to make multiple pizzas.  I found that I'll get my floor up to over 600F and then put the pizza in around 500ish.  Since the pizzas take a while with my method, the floor has come down a bit by the time the second pizza is going in.  I guess I can move the fire back over and then sweep it to the side again for the second pizza, or just make two smaller pizzas if quantity is my goal.  I also made my first 18"-20" pizza and I need to get better at launching the bigger pies.

[Jon in Albany]

Glad to hear you are firing your oven up for pizza. Hope you are enjoying your new toy!

[Pod4477]

Glad to hear you are firing your oven up for pizza. Hope you are enjoying your new toy!

I'm sorry!  For some reason I never saw your post.  Thank you very much.  A little update: so far things have been interesting.  I have had quite a lot of efflorescence on the outside of the oven (which washes away naturally throughout the week) along with some rusting of the ends of the angle irons that protrude out the sides of the roof.  I had sealed these in mortar/hydraulic cement, but the angle of the roof caused all the rain water to wash away the mortar/hydraulic cement!  I guess the roof pitch has been working.  There are only about 4 angle iron ends exposed, so I have to figure out how to deal with that.  Maybe wire brush them and paint them?  Do you guys think the rust has spread inside a considerable amount?

Also, I did one layer of stucco, and I had read to wait 2-4 weeks for do a second coat, but I have also read to not do the second coat in stucco, but rather to paint it because of freezing conditions that will occur over the winter of course.  What do you guys think?  The stucco is doing awesome through 2 minor snow storms.

[Jon in Albany]

I don't think the rust will be bad but I would try to prevent it anyway. I think it would take a lot longer (years) for there to be meaningful section loss to the angles. My only concern, and still a good amount time in the future, would be that rusted steel takes up more space than the original steel. I'm not 100% sure where this steel is, but if there is contact with concrete, the expanding rusted steel will eventually cause a crack. Some rust may have weakened the bond between the steel and hydraulic cement before it washed away. Unlessnthis is steel that gets hot, my guess is that the easiest fix is to wire brush it or maybe there is a good dremmel head to sand the rust off and touch it up with a can of rustoleum. I have never had good luck with spray cans of rustoleum. Seems to go on too thin. The paint will get you through the winter and you can address the problem in nicer weather.

I cant really help with the stucco. Every now and then I read a little about it or watch a video but haven't tried to put any up.

Efflorescence is an alkali salt moving though the concrete with water vapor. When it gets to the surface, the vapor evaporates and leaves the salt. My understanding, which is limited, is that it will stop once all the water vapor that dissolves the salt and moves it is gone -complete concrete cure with no more water being added to the system. If the supply of water doesn't go away, it can continue.

[Pod4477]

I don't think the rust will be bad but I would try to prevent it anyway. I think it would take a lot longer (years) for there to be meaningful section loss to the angles. My only concern, and still a good amount time in the future, would be that rusted steel takes up more space than the original steel. I'm not 100% sure where this steel is, but if there is contact with concrete, the expanding rusted steel will eventually cause a crack. Some rust may have weakened the bond between the steel and hydraulic cement before it washed away. Unlessnthis is steel that gets hot, my guess is that the easiest fix is to wire brush it or maybe there is a good dremmel head to sand the rust off and touch it up with a can of rustoleum. I have never had good luck with spray cans of rustoleum. Seems to go on too thin. The paint will get you through the winter and you can address the problem in nicer weather.

I cant really help with the stucco. Every now and then I read a little about it or watch a video but haven't tried to put any up.

Efflorescence is an alkali salt moving though the concrete with water vapor. When it gets to the surface, the vapor evaporates and leaves the salt. My understanding, which is limited, is that it will stop once all the water vapor that dissolves the salt and moves it is gone -complete concrete cure with no more water being added to the system. If the supply of water doesn't go away, it can continue.

Thank you!  Thankfully this is all on the roof and not the side walls, so worst case, I would have to rebuild the roof in the future.  Interesting about the rust taking up more space, I never thought out that.  So I think I should definitely sand or Dremel, and then paint.  Good tip with using a can instead of spray can. 

Same with me and stucco; I'm curious to see how the first coat does in the winter.

Thank you, that's an awesome explanation.  I wonder if it's worse because the air here is quite salty since we're near the ocean.  Does the alkali salt come from the air or is it present on the brick?

[Jon in Albany]

Thank you!  Thankfully this is all on the roof and not the side walls, so worst case, I would have to rebuild the roof in the future.  Interesting about the rust taking up more space, I never thought out that.  So I think I should definitely sand or Dremel, and then paint.  Good tip with using a can instead of spray can. 

Same with me and stucco; I'm curious to see how the first coat does in the winter.

Thank you, that's an awesome explanation.  I wonder if it's worse because the air here is quite salty since we're near the ocean.  Does the alkali salt come from the air or is it present on the brick?

I've seen it in concrete and concrete block. I suppose it could be in brick too.

[Pod4477]

I've seen it in concrete and concrete block. I suppose it could be in brick too.

Oh interesting, thank you!

So unfortunately the hydraulic cement on the roof is starting to crack, as I suspected since it was put on so thin.  So now I have to figure out how to remedy this.  I really am considering putting a roof coating from Lowe's on there, if it will adhere to the surface now that it's so bad.  I suspect I'll have to scrape it off and then apply the coating, but temps will have to be higher I'm sure.  Another idea is to just put plywood up there (thick enough that it won't shift from the wind) and nail some shingles to that, and then fill in any gaps with caulking.  I also should note that I did fill in between every brick with mortar, so I don't think any water will get in, even with the hydraulic cement cracking.  I think I could probably just use a crack filler in between the bricks on the roof, if I see any gaps.  Interestingly enough, the friend of mine who has built hundreds of ovens, has cracks in his refractory concrete roof/dome, and he said when it gets wet, he just dries the oven out with low heat for a couple days before he cooks.  Not the most economical option, but if I'm only cooking once a week it's not bad.

[Pod4477]

So I'm still debating whether I should sand/grind off the rust on the roof support angle irons.  I don't want to ruin the mortar that they're in, so I'll have to be careful.  Also, some mice got into my wood pile.  I don't care about the poop, but my worry is that the urine might be in the wood.  I don't smell any, but I'm guessing it could be in the wood. Do you guys think there would be any issues with burning the wood in the oven?  I'm hoping any urine would evaporate, but I don't want to leave any weird taste on the firebricks.

[foreplease]

Good to see you back! I don’t know for sure but would think as many fires as you will have no odors from what you describe would be long term problems. They probably had their way with your firewood before you got it.

[Jon in Albany]

I have had a few nests in my wood pile. I'm going to have to order more wood in a month or 2. Hard to believe I have already gone through a cord. After each bake when the oven is around 250-300 degrees and I'm not using it anymore, I fill it with a wheelbarrow full of wood to toast up and dry out. I don't think anything bad will last the long, slow simmer above 200 degrees.

One thing to watch out for is loading the wood in when the oven is too hot. I have done it and you get some charred wood with a lot of smoke. I thought a neighbor had a fire going in their fireplace, but it was me smoking out the neighborhood.

[Pod4477]

Hope you guys are all doing well and healthy!  Hows the pizza been?

Good to see you back! I don’t know for sure but would think as many fires as you will have no odors from what you describe would be long term problems. They probably had their way with your firewood before you got it.

Thank you.  Sorry I took some time off!  That a good point and thank you.  So far the wood seems to have no smell and just some dry poop.  Most poop comes off when he wood is tipped upside down.

I have had a few nests in my wood pile. I'm going to have to order more wood in a month or 2. Hard to believe I have already gone through a cord. After each bake when the oven is around 250-300 degrees and I'm not using it anymore, I fill it with a wheelbarrow full of wood to toast up and dry out. I don't think anything bad will last the long, slow simmer above 200 degrees.

One thing to watch out for is loading the wood in when the oven is too hot. I have done it and you get some charred wood with a lot of smoke. I thought a neighbor had a fire going in their fireplace, but it was me smoking out the neighborhood.

Oh so that's good it's pretty common.  I had to order more too; that's awesome!  That's a good tip about drying out the wood because most of it has moisture.  Yea thank God it's a furnace and not something cold in this case, so I feel it will be fine too.  Thank you.  That's another good tip as I think I've done that a few times too.  I had a few times when it was very very smokey.  I'm very happy I built it last year and not this year.  I think most places are still open, but not sure about metal supermarket. 

Now what do you guys think about the rust of the angle irons sticking though the brick.  I'm nervous that I will ruin the mortar while doing it, but I have some high heat barbecue paint from lowes that seems like it will work well if I get rid of the rust of course. 

[Jon in Albany]

All is as well as it can be here. Hope you are well too. On the pizza side, I've been firing up the oven every other weekend. Been making about 20 quarantine pizza for the neighborhood and family. It is fun, but putting out that volume of pizza is tiring. Going through flour faster than I ever have.

Not quite sure what is rusting. In general, I would say rust is bad because it takes up more volume of space. That increase in volume can lead to cracks. I think you have well over a decade before rust would hurt the strength of the angle but it could impact the mortar sooner. If there is a relatively easy way to address the rust, I'd do it. Sanding and BBQ paint or wood stove paint should last. Whenever my dad painted his wood stove, it stuck something awful for the first burn but then the odor was gone. Might get the same with bbq paint. I know a lot of grills have a first fire/curing process  in the directions.

[Pod4477]

All is as well as it can be here. Hope you are well too. On the pizza side, I've been firing up the oven every other weekend. Been making about 20 quarantine pizza for the neighborhood and family. It is fun, but putting out that volume of pizza is tiring. Going through flour faster than I ever have.

Not quite sure what is rusting. In general, I would say rust is bad because it takes up more volume of space. That increase in volume can lead to cracks. I think you have well over a decade before rust would hurt the strength of the angle but it could impact the mortar sooner. If there is a relatively easy way to address the rust, I'd do it. Sanding and BBQ paint or wood stove paint should last. Whenever my dad painted his wood stove, it stuck something awful for the first burn but then the odor was gone. Might get the same with bbq paint. I know a lot of grills have a first fire/curing process  in the directions.

Sorry!  Good I'm glad!  I doing good as well, trying to get some veggies growing.  No way, that's awesome!  I can't imagine doing that many pizzas and did you buy a 50# bag?  I didn't even think of the rust opening up the mortar but that's such a good point.  hahaha I'm not looking forward to the paint smell then!  Hmm I'll have to try and scrape the rust off slowly and carefully.  I'll get some pictures first.

[Pod4477]

So I added more hydraulic cement to the roof, so fix some of the cracking, and it seems good now.  I still have rust on the end of the angle irons, but I'll have to figure out how t sand that off without harming the mortar.  Made 3 pizzas yesterday, and they came out really good.  I dried out the oven with smaller fires and then gradually brought the heat up.  I did cover the oven with a tarp the other day, just incase any water wanted to get it. 

So far the inside seems to be fine, but I worry a bit about the joints of the ledges hairline cracking a bit from the heat.  There are hairline cracks throughout one course of bricks on the outer brick wall encasement (from the heat).  I worry most about the ledges and ledge supports, because that is what is holding up the brick wall encasement.  I'm sure it will hold though, but it's just the worry of having to do 4 pillars at the corners, instead of just making the base of the oven larger, along with a larger support slab.