Firedome: a newer version, not a complete failure, just some notes

The Firedome project is my pride and joy. Although I can rely on it for pushing out a nice pie for friends, I still play around with ideas for changes. Here's a newer version that didn't quite work as I wanted, but the final cut shown in the last image reveals what may be a slightly better design than the current one.

The unsuspecting lid generously dropped off by @CMHGourmand, you will be rewarded!

The lid secured to the chopping block. I use duct tape in order to visualize where to cut.

I cut it with an angle grinder and the edges smoothed with a dremel/mini grinder wheel.

Assembled, ignition time. I use a few Matchlight briquettes and then toss in logs. Voosh!  Warmup of the stone inside takes about 30 minutes.

The other, and still functional, lid (thanks @ToKateFromKate) sitting beside the newer design. Notice the closer crop/smaller section removed.  I  also did away with the door, I've never cooked with it closed.  The intent was to see what the convection would be like with a closer-cropped opening. I got lots of smoke - bad! Very surprising given the size of the opening.

 A sample pizza (ok four) were run through for a test (and light lunch). They were uniformly cooked, but the opening made it a pain to get them in and out and feeding wood was also tougher.

Here's another shot where the thermocouple probe wire is visible (on the left). I placed the probe in the side away from the fire (the "cool" side) hooked up to a datalogger. I maintained ca 800-850°F with an occasional spike. The surface of the stone stayed about 800°F at the center.

The temperature profile on the cool side, the probe was placed just below the cooking stone.  It was a short cooking session, this is the hour after a 30 min warm-up.

Given the amount of smoke I saw during the burn, I ripped it open to look more like the previous design opening - only larger. I've opened about a full third of the perimeter. I'll give it a shot tomorrow night.  I'm essentially back to where I started (which wasn't a bad place), but I may have slightly more convenient access.  Incidentally, I get about an hour and a half of high temps from a $5 bundle of grocery store wood.


Anonymous said...

Hey Dave,
Do you think the addition of a small smoke stack would help with the smoke problem? You could put a damper in it al a wood-burning stove.

Other Dave

ooh, ooh, I have something I will draw and send to you via email.

Jon in Albany said...

I'm not exactly sure how the number came about, but 63% is the ratio of door height to dome height thrown around in brick oven circles. Door width is usually pretty close to dome height. That's the door dimension I shot for in my rip off of your design. It works pretty well. I still have to work on getting more heat to reflect down from the top.

I've been considering cobbing some kind of support to hold a pizza stone or fire brick in the lid to send some of that heat back down. My other idea was to drill holes in the lid and attach bolt with the heads out an inch or two into the dome. Then use the bolts as shear studs to hold in a small batch of refractory cement. I'm not sure the lid could handle it though.

Jon in Albany said...

I should clarify "brick oven." I'm referring to Pompeii style dome ovens. I've seen the 63% a few times in web forums focusing on that kind of oven.

Dave said...

Hey Jon,
Yeah, the 63% was given to me by a coworker who reads more than I do. I'm more empirical on this since it simply isn't anything like brick.

One's the dome's cut, I don't think it's going to support any weight at all, the arch is totally compromised by the cuts.

Getting the top to cook more is the most common complaint among a few people who tried this. The solutions usually involve lots of shields, deflectors, etc. I think the final step in the whole operation is beyond equipment. For me it took a long time learning how to work with the live flame, it's not trivial.

@Dave I think when I saw the smoke coming out I was thinking of the smoke stack / chimney to let it out. But then I chickened out and lopped off more the dome. So, kind of late. My next one may implement a chimney. It will likely involve drilling and riveting. Because of the stress on the top, I'd have to install it before the side is cut, just for support.

Dave said...


I want to correct something. I don't think putting in deflectors in this is actually a solution, I meant to say it's been done by others. Frankly, if this wasn't a simple solution to cook pizza, it's not worth it, I'd figure something else out. So, think about other elements of your dome for uniformity of cooking: surface, wood (all supermarket bundles are actually not created equal), etc.