Bill of Materials

Current Cost of Project: $1,147.50 (includes Hawaii Excise Tax)

Hollow Tile 6x8x16 Knockout, 16 each @$1.57
Hollow Tile 6x8x16, 22 each @$1.67
Hollow Tile 6x8x8, 4 each @$1.17
Wonderboard 1/2 inch $12.67
Mortar Mix Quikcrete 60lbs.  $8.87
Rock Gravel 3/4inch 1/2 cubic feet, 4 each @$6.69 

Rebar 3/8 inch roundcut 10 feet, 2 each @$5.59
Rebar 3/8 inchx10feet, 2 each @$5.59
Rebar 1/2 inchx10feet, 4 each @$7.29
Sand 0.5 cubic feet, 14 each @$6.99
Cement 94#, 3 each @$16.27
Wooden Dowel 1 5/16in x 8 feet @$11.49
Chicken Fencing @$17.68
Aluminum Parts for Expensive Insulated Door @$125.10

Insulating Cement, 2 each @$53.77
Sairset High Temp Mortar 55# Pail @$51.10
Firebrick, 24 @$0.50 
Firebrick, 90 @$3.22
3 1/2 inch by 15 inch by 32 feet Insulation @$9.81
3/4 inch by 10 inch black pipe @$3.42
Vermiculite 6 cubic foot bag @$45.70

HPGX-2 Burner @$128.85

 

Color Legend: 

City Mill Honolulu

Pacific Refractories 
Reuse Hawaii 
Tileco Inc

Home Depot

Pacific Agriculture Sales

Teja's Smokers

A Door Is Born

Okay, I am designing an insulated aluminum door for the oven. The shiny aluminum will help reflect some of the heat back into the oven and what gets by will be handled by the 3 1/2 inch thick insulation I got from Home Depot (plenty leftover.)

The parts of this door I got from City Mill for $125.10.

Yeah, big big money.

But take a look at this door! What a honey it turned out to be!!

Two pieces of aluminum cut from a template I'd made earlier to fit in the arch doorway This shows the construction without the insulation.

And here it is with the insulation in:

And it's fitting nice and snug into its spot:

 

I must say that the aluminum door gives a nice finished look to the oven! Also the shininess of the Aluminum will reflect some heat back into the oven from the inside.

Initial Firing of Oven

In between laying on the insulation and then cementing over with a vermiculite cement mix, I did an initial firing of the oven with kiawe wood (aka mesquite wood). Kiawe wood grows on the arid places on the island. Historical note: It was initially brought over by catholic missionaries, and the first kiawe stump can be viewed at Our Lady of Peace at Fort Street Mall.

I bought $220 worth of kiawe wood cut up 18 inches long and around 3 inches in diameter. I found John off of Craigslist:

Okay, firing up the oven with the kiawe wood. If this is what it is going to take i.e. tons of smoke and soot all over the place, 2 1/2 hours or so to do, then horrors!!!

But fear not as one of my thinking way ahead ideas was to use PROPANE to provide heat to the oven. I searched online and settled on this cast iron burner from Teja's Smokers:

The great thing about this burner is that "ANY LENGTH" part. That is the pipe that connects the propane/air baffle mixer to the actual burner itself. In other words, the air and the propane is mixed OUTSIDE OF THE OVEN and then "piped in" to the burner that sits in the oven.

And that is exactly what I did:

Propane hookup and air mixing vane that's OUTSIDE the oven proper. And below is the burner at about 1/2 maximum:

This particular burner puts out 160,000 BTU per hour. That heat capacity is about the heat output from a medium wood fire. In heating up your oven, you don't want a hot hot blast of fire that will just use up all your wood (or propane in this case) for no good purpose; you want instead a steady heat source that will slowly heat up your oven's thermal mass.

And this HPGX-2 burner from Tejas Smokers does the job most excellently with NO smoke, No ash and No wood or wood babysitting!

Since this propane burner is cemented into the oven, it will be considered part of the oven building process, so one HPGX-2 burner from Tejas Smokers for $128.85 (including pressure regulator) delivered to me in Honolulu. I also got a 3/4 inch by 10 inch black pipe nipple from Home Depot for $3.42.

Hmmmm. Looking at the pile of kiawe wood (mesquite) I got for $220, that is the equivalent of 11 tanks (20 lbs. per) of propane refills from Home Depot. Having burned some kiawe wood already, I am quite positive that 11 propane tanks will outlast that $220 pile of kiawe wood I bought. So it is a win cost wise too (along with no ash, no smoke to bother my neighbors and no babysitting the wood burning!)

Insulation of Oven

To start, I placed aluminum foil all over the dome like so:

This will reflect some of the heat back into the oven. I had some spare rolls of aluminum foil in my kitchen.

I also picked up some 3 1/2 inch thick insulation batting (15 inches wide by 32 feet long) from Home Depot for $9.81:

That along with the chicken wire I purchased earlier from City Mill ($17.68) was applied to the outside of the dome:

The insulation from Home Depot was the easy to cut and assemble. I used a plain desk stapler to join the layers together (I initially used duct tape, but believe me staples work much much better and faster too!)

I then applied a vermiculite cement mixture over the paper backing of the insulation, embedding the chicken wire into the vermiculite mix for strength.

 

I bought the  6 cubic feet bag of vermiculite for $45.70 from Pacific Agriculture Sales at Campbell Industrial Park, 91-262 Ola'i Street. Phone 808-682-5113.

  

When everything is finished, I'll have around 7 1/2 inches of isulation around the top of the oven's dome and around 5 1/2 inches all around the sides.

I picked up another 94 pound bad of Hawaiian Cement from City Mill for $17.04.

Brickwork Completed Finally!

Yup, no more making dust by cutting up bricks! Check it out (note the rectangle box on top that will help brick in a future 6 inch stove pipe to vent out smoke):

See that archway? That was the hardest part thus far. Lots of cutting and grinding with the makita outfitted with a diamond saw. PLENTY OF HOT, NOISY AND DUSTY WORK!!!

That glob of cement on the top of the oven dome is what was left from my mizzou refractory casting cement. It should act as additional thermal mass, like a cladding of sorts. I don't want to add too much thermal mass as that would take additional time to heat up the oven to proper temperature with a wood fire.

For baking breads, if there is not enough thermal mass to last a bake then I could always place in some leftover fire bricks along the perimeter of the hearth deck to act as a temporary thermal mass. I also am thinking of a small fire by the archway to act as a heat source (a real fire door!) to maintain a proper temperature of an otherwise "falling" oven.

So a "quick" warm up to 900 deg F. for pizzas and tandoor type flat breads and then for bread baking, additional thermal mass added ala loosely placed bricks to maintain a 450 deg F. temperature bake. (Can't wait to try!)

The section below the oven's entrance I plan to place ceramic tile:

And below everything, that perfect spot for wood storage:

Major Brickwork Done!!!

Oven brickwork pau (done). Each brick besides the first soldier course had to be cut individually with different angles all the way around. It was very time consuming, dusty, noisy (cut with a diamond blade on a makita grinder) and a drag to do.

Steps in making the new arch doorway:

Cutting the keystone (two) that betweenist will become the chimney smoke stack.

Looking at how things turned out, the two bricks to either side of the keystone are probably the weakiest points of this arch. However things should be strong enough to support a future stainless steel smoke stake (crossing fingers).

Doorway Redo

Here's the latest progress picture:

Yup, got the dome all completed, bricked up. And was it a pain!  Each brick had to be cut individually and had different angles, sometimes on all four sides! I read online that refractory brick manufacturers made specially angled cut bricks for dome structures. Good luck finding such firebricks here in Hawaii.

But oh, where's the door archway that was there before???

Well, the insulating cement (that one with wool in it) never ever cured; it remained plastic enough that I could push my finger into it, all the way thru! As a result, the old doorway arch (with smoke chimney) started to lean about 1/4 inch, which threw things off a lot.

So I dismantled the archway completely. Then I lit a propane burner below the platform to heat up the insulating cement slab from the bottom:
 

I left the burner on for 24 hours at full flame.

Finally the insulating cement is hard and I thought cured. Then it rained heavily and where the water touched the surface of the "cured" insulating cement, the cement turned plastic again! It seems that this insulating cement is not for wet environments and will disintegrate if subject to same.

Once I get a ceramic insulation blanket on with an outer layer of stucco, there shouldn't be any moisture reaching the insulating cement. I also will redesign the archway to look more like that one I made for the olympic arena a whiles back.

I also lit a fire in the dome to help dry out the refractory cement that I used to cement the dome's firebricks.