Tuesday, March 24, 2009

Wood Fired Oven: The Brick Front

It was time to cover up my very pretty firebrick arches. But it had to be done. My bud Ben and I were done in a few hours.
A couple-ah-sixpacks later, this is what came out. It looks pretty neat in real life. These pics are a little misleading. The reclaimed brick makes the work look as if it had been there for years.

Now, onto the walls and chimney. But before then, I will begin curing the oven. I will start by burning small fires every day--in 100deg increments until I reach full bore: 1200deg F. That will make some mean quick-fire steaks. Man, I'm hungry. Gotta go.

Tuesday, March 17, 2009

Wood Fired Oven: Dome Rising

OK. So, it's been a while since the last post. Forgive me for being "busy" and covered in refractory mortar. That stuff gets everywhere. I also got that crappy cold that lasts weeks. But, significant progress is being made. Take a look at the next sequence of pics. We have a chimney vent, the dome is but three or so courses from being finished.
This coming weekend (March 22-23) will be the last firebrick cutting weekend. Cutting firebrick is nasty with a cut-off saw. No more breathing alumina particles into my lungs causing unknown havoc to my respiratory system. I will soon be calling a trial lawyer (e.g. Shapiro Injury Center) to sue someone because I AM NOT RESPONSIBLE FOR MY OWN ACTIONS. Therefore, I will cash in on my own stupidity. After the last dome brick is mortared in place, it will be time to cure the oven and make it pretty. I just hope it doesn't look like some third world hack job used for cooking goat and weird things like millet flatbreads. Not that there's anything wrong with goats and flatbreads. It's the aesthetic part that concerns me. I'm looking for more of a Provence or San Gimignano look than a Nepalese mud oven. Does this make me an oven snob? Probably. However, the thrill in all this work is trying to do it right.

Tuesday, February 10, 2009

Wood Fired Oven: The brickwork begins

Finally, I got the firebrick. We started by layng down the oven floor. We worked this out on the computer first by laying it out on MS Visio. It's not autocad, but it's what I have. It did accurately work out the floor and opening.

Next, we cut the circumference of the oven floor. Once the cutting was completed, I layed down the bed of fireclay and sand with a notch trowel and began puting the puzzle together on the hearth. We also cut many, many, many half bricks for the dome construction.

The next day, I began mortaring a soldier course along the perimiter of the floor. This will serve as the base for the dome. I also started working out the inside arch at the oven opening.

I have to take a weekend off to go camping. But, when I get back I will continue working my way up the dome.

Tuesday, January 27, 2009

Wood Fired Oven: Hearth

Forming up the hearth involved doing something I'd never done: Vermiculite concrete. This is a strange mixture to say the least. The base slab for the hearth was something very familiar to me. The texture and feel of the insulating concrete was not. It seemed that, as we mixed the vermiculite and cement mixture and added water, the thirsty vermiculite soaked all the water we threw at it. I was afraid of weakening the batches by making them too soupy. Yet, the 'oatmeal-like' consistency called for by the Forno Bravo (http://www.fornobravo.com/) wasn't the easiest thing to work with. We ended up adding a touch more water for workability (if that is a word).
Here's what makes me nervous. After three days, the insulating layer seemed to still be a bit on the soft side. It could be the water retention qualities of vermiculite...or the thickness of the entire lab curing ever so slowly. The consistency of the vermiculite portion of the slab is sort of like clay prior to being fired. Nonetheless, I was concerned that I screwed something up, although I have read in forums that the mix never hardens like normal concrete. I guess only time will tell. Ho bisogno di pazienza. Pazienza e una virtu. By the way, the picture on the right shows a bow in the slab...it must be an optical illusion from my phone's camera. Really...it can't be poor craftsmanship ;)

Friday, January 23, 2009

Afterglow from January 8th

I'm finally coming down from a massive sports high. My University of Florida Gators defeated Oklahoma in the BCS Football National Championship Game. I was extremely nervous about the outcome. I thought Oklahoma's offense would do some serious damage. But UF's defense kept making key plays and in the fourth quarter it was decided. What a relief.

All I can say is Go Gators!

Wood Fired Oven: Forming up the Hearth

Our next step is the hearth. The hearth is made up of two layers of concrete: one structural 3 1/2" slab with rebar and wire mesh and another on top made up of insulating concrete. This insulating concrete is made by mixing cement with vermiculite to make a fluffy lightweight concrete having insulating qualities. We'll try the pour this Saturday if the rain holds up.
To form the interior part of the stand we built braces to support the OSB deck. These are not fastened to the structure since the weight of the concrete will hold them in place. Look at the 2x4 cleat around the perimiter of the block stand. It is screwed into the block with TapCon screws and will support/line-up the 2x8 hearth forms.
A note about green building: We strive to use as much reclaimed/recycled materials in this project. My friend Ben has acquired the great majority of the lumber from construction site dumpsters (with the builder's permission). This included rebar, 2x4's, 2x8's, plywood. He could have enought to build an addition to my house, but he's too busy to scrounge all day for me! It's amazing how much builders waste in building homes. You would think that in a tight economy, they would revisit their building practices to conserve materials. We've saved quite a bit in material costs.
Next blog entry we will detail the pour. After the hearth comes the meat and potatoes of the build--the brick oven. Thanks to my brother-in-law Lance, I now have a brick cut schedule for each course of the dome. I wish I knew AutoCad. I am, though, working on Google SketchUp to mock up the look of the oven. We'll see how that turns out.

Monday, January 12, 2009

Wood Fired Oven: Building the stand

The next step after forming and pouring a foundation is the building of a block stand to raise and support the hearth. The block stand was built with standard 8x8x16 block. We used a dry stack method where the joints are not mortared but every other core hole is filled with concrete and rebar. It's easy for us non-mason folk.

We also were going to pour in place a lintel. But after much debate with my friends, we used angle iron instead. I figured, this is my first one, let's not complicate matters.

After the block cures we'll form and pour the hearth. It will have to be when I get back from a mini-vacation to Tennessee.

The hearth is composed of 3.5" of structural concrete and 4" of vermiculite concrete. Vermiculite is added to cement to make an insulation layer for the hearth. I scoured the city for vermiculite and couldn't find it readily. I had read that some folks found it at Home Depot. When I called my local HD, sure enough, I found they had 10 bags each at 4cu ft of medium grade horticultural vermiculite! The lady said the price was $12.95--incidentally much cheaper than any other place I found. But when I arrived there was another surprise...they had vermiculite on clearance at $9.00!

We'll see how well we frame up the forms for the hearth. So far...so good.