Wednesday, May 29, 2013

Outdoor Oven Building DIY Workshop.

Over the Victoria Day weekend I had the awesome opportunity to attend a three(ish) day long, hands-on oven building workshop in Perrault Falls ON. The workshop was hosted by Tom and Margaret of Sleepy Dog Cabins, and instructed by  Derek Lucchese from Both Hands Bread.

Tom and Derek had already decided on dimensions and materials long before the workshop began, and Tom had taken the time to pour a slab and lay the cinder-block foundation that supports the oven before any "students" had arrived to remove a large and time consuming step of construction.



This is what I saw when I rolled into Perrault Falls Friday evening. Derek and only one other student fitting a square form for the concrete pad we would be pouring on top of the cinder blocks. We used chip board (OSB, Beaver Puke, whatever you want to call it) as our base and 2x4's as the frame, and laid a rebar grid inside to support the concrete.


Derek has a great, laid back but focused teaching style, and his sense of humour is pretty great for dispelling any chance awkwardness had of cropping up when it came to strangers from all walks of life getting together and working closely for three days straight. Making jokes about how the oven was going to be so over-built a bomb could go off in it was a great way to break the ice. 

At the front of the oven we had to cut out and fit a form into what would become the "ash drop" or clean-out (while we were shovelling cement into the slab form). Since these types of ovens use wood-fired heat, you actually light the fire inside your oven, on the stone(brick) hearth and allow the oven to heat for hours prior to baking. But with a fire in the oven, things are bound to get ashy and dirty so that's where the ash drop comes in. When the fire goes out you scoop/sweep/mop the ashes and coals forward and down through the ash drop into the cavity below where they cool and can then be further removed. You could use the space under the oven to store fire wood, but you'd likely want to modify so that there was a separate space confined from the hot ash and coal. Safety first!

After shovelling cement and smoothing it level that was a wrap for our first session. Not much you can do with un-cured cement but wait.

Derek's workshops are interesting in that there is very little "classroom" or "structured" instruction, it's pretty much all hands on learning, demonstrated and executed as you go. On Saturday morning we had morning coffee/tea in Tom's shop while we recieved our only "classroom" instruction. There was even a chalkboard!


Derek went over the basic components of construction that we would be tackling that day, and afterwards if any of us were going to pursue building our own ovens after the workshop. For the most part the materials used for the oven are fairly common, cinder blocks, cement, rebar, firebrick, angle iron and cement board. The only truly specialty materials we used were the rigid insulation (Calcium Silicate), refractory mortar and threaded iron.

So on Saturday, we started by measuring out our oven square on the new slab and marking with chalk lines. The rigid insulation came in 2'x3.5' boards and had to be cut to fit with a hand saw, two layers high before being topped with cement board. we "glued" each piece and layer in place with small dobs of mortar, to avoid any shifting during construction. Then we got moving and started laying out our courses.

{two layers of CSRI and cement board under fire brick}
With refractory mortar, you do not want to see any large joints, as its strength comes from the bond made in thin layers. We were encouraged to aim for 1/8" or less joints, as refractory mortar is actually quite brittle when applied too thick. Because refractory mortar is water soluble, you actually wash the faces of your bricks and joints to make it look nicer and not so sloppy (like in the above picture).

After we had three courses laid, we set out the hearth. The hearth is composed of two layers of brick. The first layer is dry-set directly on top of the cement board, in the opposite direction of the top layer. The second layer of hearth brick is not mortared to the first in typical fashion, but instead using silica and water to create a fixative that provides some degree of easy removal in the future if any bricks crack or are damaged.

{hearth going down}
To avoid some of the guess work of "is the oven hot enough?" we drilled a hole (using a masonry bit) in one of the hearth bricks and set a probe inside. The wire for the probe is barely visible in the picture above, but it was set under the top hearth and led through to the outside of the oven where it will be connected to an external temperature gauge. Our instructor said there are other methods to gauge the internal temperature (like sticking your arm in and the finesse that comes with years of baking in the same oven) but infrared laser gauges tend not to be super accurate in this instance and conventional thermometers will simply explode. He recommends getting a probe for all you folks out there itching to build your own.

After the hearth was set, we covered it in vapour barrier to create a drop cloth and avoid 'contaminating' the hearth. You want your hearth to be as food safe as possible since you cook directly on the brick, which is why the hearth bricks aren't mortared but rather only held by silica paste on the bottoms of the bricks. Mortar will break down over time and can flake off into the food being cooked in the oven. Mortar would also make it mega-hard to remove any damaged bricks.

To make up the height deficit created by the hearth, we laid three more courses of brick before calling it a day. It doesn't look like much, but man, laying brick takes a lot longer than you'd think (especially for amateurs).

{Saturday's progress}
 We were back at it bright and early on Sunday getting ready for the next stage of construction: determining our arch height and setting our arch form before building the arch (or roof) of the oven.

To determine your arch height for the oven you take the total height of your current opening (ours was 10") and minus it from the 'optimal opening height'for an oven this size (4'x5' base), it tends to be 16-18" high— which left us with six inches. Taking a piece of OSB we marked the width of the opening (18") as well as the centre point and from the centre point up to the six inch mark. To create our curve we used a piece of flexible flat metal, but you can use anything that is rigid+flexible with a straight facing edge. 

Before cutting our form curves, we used a sliding T-bevel to find the starting angle of our arch and transfer that to the next course of bricks that would bare the brunt of weight and support the rest of the arch. While the form curves were being cut, the rest of us got a quick demonstration of how to cut the bricks before doing a few each. 


{hands on learning!}
We were lucky to be able to use Derek's masonry saw during the workshop, but for those DIY'ers out there a wet tile saw can do the trick (if you're willing to go through one or two blades). After our bricks were cut and the form in place we were able to get a moving laying the next courses. 

{arch form in place}
After laying our cut side courses (tying into a solid, un-cut back wall), we secured the walls with two pieces of angle iron connected by threaded rods, and bolts. The idea is that the arch pushes out against the cut course that is supporting the entire weight of the arch. To keep the oven from falling apart or ending up askew, the angle iron+rod brace is put in place simply to make sure everything stays put while you work.

 Only the one course was cut, the bricks that came after were laid on their sides so that there was a uniform 4" shell of insulating fire brick throughout the entire oven. If we had lain the brick on their "beds" as we had for the walls there would be two inches less of brick on the roof arch, and we all know heat rises. Heat loss with this style of oven would be pretty awful, SO there's the logic behind that for anyone wondering.


{starting the arch}
As we went along, the inner joints reduced as the outer joints increased. This is typical of any arch being built with rectangular brick, even though as we progressed to the top of the arch bricks were "shaved" to create a better fit. For those of you paying attention, refractory mortar is no good if the joints are too large, and what you need most in an arch is strength. So Derek whipped up something he called "grog" which is basically a combination of ground up fire brick and refractory mortar. They way it was explained to us is that the mortar is coating each and every minuscule grain of busted up brick creating multiple thin layers between the large joints, making it stronger. 




{big ole groggy joints}
A second probe hole was drilled into one of the arch bricks so that there will be two relative temperatures—one for the hearth and one for the temperature of the air inside the oven. At this point we were all really pushing to get the arch finished, it had been a long cold rainy day and we could see everything coming together. That and someone still had to climb inside the oven and clean up the mortar joints that were hidden by the form. 

{almost there..}
That someone was me. 

Being the youngest in the group by a good 15-20 years and also small enough to fit inside it only seemed logical I volunteer. Maybe I just wanted to feel special. Who knows. But in I crawled Hansel+Gretel style with a sponge and an improvised mortar board to tackle those joints.

Not gonna lie, I'm pretty diy-frustrated I didn't get a picture of my feet sticking out to prove it, but hey, it was hard enough to snap quick shots at each stage of the build. 

After spending an hour inside the oven, I can honestly say it really wasn't that bad. Maybe because I was small enough to roll over on my side. I can definitely see a slightly larger someone having a heck of a time moving their arms in there. I also got asked a lot of questions about being claustrophobic, for the record smalls spaces are safe spaces to me and my inner hibernating human. So no, I had no qualms with the task. If you don't like small spaces, pass this one on to someone else. 

Monday flew by really really fast. Faster than I could snap pictures. We were on site at 8am and cleaning up by 10.30am. We started by laying out the brick that would support the granite sill (or whatever it is actually called)  that covered the gap between the front of the oven and ash drop, again attached by dobs of mortar. The granite was cantilevered out off the base approximately 5" and supported by 2x4's so that the weight of the chimney wouldn't collapse the front before the mortar set. 

We reused our arch form to create a second, identical arch in the chimney. Though not shown, there is a piece of angle iron in the back of the chimney (for support) in which the bricks are dry laid the metal expands at a greater rate than the brick, so adhering one to the other is not a great idea, unless you want a cracked and crooked chimney. 

Due to some mis-communication we ended up having just not enough refractory mortar to finish the base of the chimney. So we pre-cut and dry fit the bricks so Margaret (who took the workshop last year) could finish the job once the rest of their materials arrived. Where the box is being held on top of the chimney (for demonstrative purposes only) a clay chimney liner will be placed and then wrapped in fire brick. 


To finish the oven, a water tight facade will have to be built to protect the refractory mortar. This can be done in any number of ways with pretty much any material you like, though Tom is leaning toward a beehive-style finish for his. Something like this: 

{source}
Between the outer facade and the actual oven the space will be insulated with Ceramic wool or mineral wool/rock wool (comes in green batts like pink insulation does) to retain as much cooking heat as possible.
Once the facade is done, a "plug" (door) will need to be custom fabricated out of two layers of metal (preferably something with high heat & corrosion resistance) with ceramic wool as an insulating layer between. A handle is then secured to the front from the outside and voila! Your outdoor oven is ready to be fired up for pizza, or bread.. or pie.. or practically anything you'd bake in a conventional oven!

Going to this workshop was an awesome experience, I learned a new skill, met some really fantastic people who were phenomenal to work with, brushed up on my teamwork skills and got to spend a long weekend at one of my favourite places in North-Western Ontario. All in all a great long-weekend. 

I would absolutely recommend attending a similar workshop to anyone who is remotely interested in outdoor ovens and has DIY-aptitude. I've never set a single tile or brick in my life before taking this workshop and it was really empowering (I can still hear Eleanor shouting "OWN IT!" while using the big bad masonry saw). I've always been one to encourage others to push their boundaries and try new things or learn new skills but am not so great at pushing myself to do the same. Taking this workshop was an amazing eye opener to the things I can do (with a little guidance, help and know-how) and what can be accomplished when you step outside your comfort zone.

So who else is ready to build their own outdoor pizza oven? I know I am. 


 

Wednesday, May 15, 2013

Vancouver Recap

I really cannot believe that our trip to Vancouver was almost a month ago. It was a short, completely last minute whirlwind trip, but I wouldn't have changed a second of it. Jesse and I never got to go on a typical "honeymoon" when we got married two years ago for a number of reason (mostly due to time off & how frugal we are), and I personally haven't been "away from home" (read: mothering) for more than 24-48 hours in over six years. 

I'll give that a minute to sink in. No adult-only vacation time for six years. That's a loooong time.

Now that you can fully appreciate how much I needed some time away, on to the pictures! (for those of you that follow me on instagram, you've probably seen a lot of these).

We drove to Winnipeg with four of our closest friends on a Friday, met up for a delicious dinner at Viva with some local friends and had a night cap before we caught an early flight to Vancouver for an extended weekend with friends. 

{Sorry, no awful early morning pre-flight pictures to share, no one really wants to see that anyway}