Kempton Pizza Oven in Arizona

Hi there! I’ve been working on the weekends to make progress on my oven and I have finally gotten to the part where I will put the foam form up and start building that… however I just realized I may have made a huge mistake.

As you can see in the picture I have modified the cooktop to have a hole lined with firebricks to allow for a propane burner (sourced from Ward burner systems) so that I can use it without wood potentially or just to light wood… anyway that is all to say that I had a little more complication as it relates to cutting the firebricks for that area and ended up having some cuts I’m not all that proud of. Also, since the surface ended up being a little higher than the full length of those bricks I ended up needing to grind down the cooktop bricks around the hole to slope down and hopefully have a smooth-ish surface.

Ok that explains the weird thing I did, but here are my questions…

  1. The red bricks around the top… I only now just realized that I was supposed to use fire mortar around the perimeter. I read the instructions 100 times but somehow missed that until now. I guess I just associated those bricks as not getting hot so I didn’t logically tie that step in properly. Sooooo… Do I need to tear this out and redo this? I hope not, but there will never be a better time to do it.
  2. The perfect flatness… It’s far from perfect but the peel moves ok across the top and I wondered if using my concrete polisher to get the top more perfectly flat would be a good idea. Again, there will never be a better time than now, but do you think that’s going too far?
  3. Filling the cracks with firebrick dust. I have dust leftover from polishing out the height differential of the “hole bricks” to the cooktop and if I do item #2 above I will have more dust. Is it a bad idea to try to fill my gaps with firebrick dust? Or will it be problematic for my food?

I think that’s it. I normally consider myself pretty handy but masonry work has proven that I have a very long way to go!

Hi Curt and welcome to the BrickWood forums!

You are venturing out into extended usability country with your build, and I want to emphasize first and foremost that you’re doing great.

So let’s knock down the issues point by point.

  1. In my opinion, it would be ideal to have the fire-resistant mortar on the framing bricks. That being said, fire never touches them. I would never advise a builder to use standard mortar there intentionally, but I don’t think you have to knock it out and start over.
  2. Never, never grind brick! Your firebrick are set on sand, and they are all trimmed to size. They will eventually heave a little, which is why you have them set in a herringbone pattern. If you are really unhappy with how they are sitting, you can cautiously pull them out a section at a time, re-level the sand underneath, and set them back in place. But please do not grind them.
  3. Yes, filling the cracks with firebrick dust is a bad idea. In fact, it is an Epic Bad Idea. Don’t breathe it, and don’t ingest it. The wood ash will fill in the cracks for you.

Hope this is helpful, Curt. I think your build will be amazing when you finish!

That was awesome feedback! Thank you so much! I will be sure not to use any dust to fill the cracks and I can see that there are health hazards to it.

Do you think there are health hazards that go along with the grinding I did to the the “cupping” around the burner hole? I thought I wouldn’t want ridges back there to sweep the ash around, but maybe I should pull those bricks? You said grinding bricks was a bad idea in general but you didn’t mention why and I’m hoping that what I’ve already done wasn’t a dangerous thing.

I hope you know what a great service you’re doing with your encouragement and sharing of tips! Thanks again!

Thanks for the kind words! Always glad to help.

I should clarify: grinding is an issue when you can’t control where the dust is going. Grinding down the surface of your hearth would in effect be the same as filling the joints with firebrick dust.

For the limited area where you set up your gas supply line, you were more likely to have had your dust under control. I’d hit the area with a shop vac followed by a wet cloth. It will be covered by the burner so you won’t be putting food in that spot anyway.

I say all this to ease your mind. You’re doing fine, and for the record I think the cutout area looks good too!

Thank you so much! I will carry on with this knowledge and I will definitely be getting the shop vac out to make sure I keep it clean :slight_smile:

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That’s Matt being a stud bud! Mr Kempton - I’m in the Grand Canyon state as well and finished up an oven last year. If you need any help or just want to bounce stuff off, let me know! :cactus::cowboy_hat_face:


Yeah @bikerbudmatt is definitely a stud! :smile:

I’m out in Queen Creek, what part of the state are you in @AZDon?

I made some more progress last night… I normally am much more of a perfectionist, but masonry work has a way of taming me-- between running back and forth to the water/brick wheelbarrow, making sure my mud doesn’t dry, lack of coordination, mixing up new bags of mortar, and sadly running out of daylight… but it is now “in stone” as they say as I now let he high temp mortar dry.

I still need to add the chimney and then wrap it up in blanket of course, but I just ran out of daylight, mud, and energy.

So I cleaned up all the firebrick dust:

Then I aligned the form (I didn’t read the posts about oiling the form until last night after I had a panic attack that I am sure I got too much mortar on the form and now I’m sure it will be a bear to remove):

And then I went to work. I am wondering though… there wasn’t a bunch of advice in the instructions about cutting the bricks for the sides of the back wall. at that point the sun was almost down and my mud wasn’t as wet as I wanted it to be so I just built the side bricks kinda speedily. Do any of you think I have any problems with the way I did the side bricks of the back wall?

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Damn, - looks good son! I am either in Scottsdale or Payson. Oven is in Payson, but I am down in the valle now. Got some extras- blanket and fire mortar if you need. I’m always up for a ride to see your handiwork- just let me know. Phone # is (602) 291-1020. Finding the materials was my hardest thing last year, but Marvel and AZ brick yard helped out considerably- hauling that stuff up the hill was a pain though. Looks as if you got good mortar coverage - it will be interesting to see when you pull the form - I did oil mine and pulled it before I did the back wall, but no biggie. Starting to get warm - always make the mud “interesting” - I think you know what I mean…:cowboy_hat_face:


Btw- I did my back wall the same way. You might consider - what I did was went ahead and used firmorter to fill in the gaps to make the barrel smooth rather than trying to cut a bunch of brick. Don’t know if it matters much, but for me it made wrapping the blanket and stuccoing easier and smoother…cause sometimes I am dimensionally challenged!!:rofl::cowboy_hat_face:


Well, here’s my stud-bud confession: I did the same thing as well. I did use my grinder with a diamond wheel to try to approximate a curve, but the truth is that those side bricks hang out into the arch space and are serving no refractory purpose. So yes, using some high-heat mortar to smooth out the curve is fine, and also ensures that you didn’t leave any gaps between the back wall and the arch, because that legitimately would not be good.

Ultimately, the back wall is covered by the blanket (double layers here in the North) and stucco, and all you see of it is the interior.

One way or another that form will come out. Weirdly, I found that using my Sawzall, “Precious,” to cut it carefully into sections seemed to be the best bet.

And one last comment, @ckemp — you’re putting the finish work where it matters, and I’ll say again that you really have no reason to be ashamed of the cuts you did for your burner.

Yeah I couldn’t have done it without Marvel. There is no fire clay in the area that I could find. Premix was the best I could do, but I have 150 lbs left for the chimney. I think I’ll use the rest as you were mentioning to make sure that as @bikerbudmatt was saying, I will not have any chance of separation between the back wall and the barrel.

Yes! My sawzall will be on the operating tray… I’m pretty sure that with all the mud that got down to the form it will be a handy guy to have around!

Seriously your support and enthusiasm is awesome! I appreciate it and I can’t wait to see if the burner is as great as I hope it is :slight_smile:

And @AZDon I’ll try to give you a shout tonight. We’d love to have you out… I won’t have any woodfired pizza unfortunately… Not yet.

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I had the same question and asked Brick Wood ovens . I was told that I could use regular mortar . This would be a change made to the next instruction revision. Your oven is looking good .Is that cutout in the rear for a gas burner ?

Thanks for the feedback @Jfritz!

Yes the cut out is for a burner. I dot it from Ward Burner Systems and it looks very different than any burner I’ve ever seen before. I will be sure to post pics once I get back to that part of this.