Capt Jon's Cob Oven

[Capt Jon]

As promised over in the intro section, here's the start to my cob oven thread. I'll update it a bit at a time until I get it up to date and then post as I go through stages.

The planning stage a couple of months ago...

[Capt Jon]

Re: Capt Jon's Cob Oven

OK, it looks like whatever site issues were going on may have cleared so, it's story time....
The photo above was my initial thoughts on the layout. The oven and a counter that will lead into an "L" corner. Eventually, that would be a three tier brewing system but, that's another story.

The photo below...the basic blah beginnings...digging holes, forming, mixing, pouring. Feeling both good about doing the work myself and aching because I don't do as much of this type of work anymore (office job).

Keep in mind, this was a couple of months back so now I can say it was easy. I do have to acknowledge that the neighbor did lend a hand on toting crete, mixing, pouring and leveling. 19 each 80 lb bags of crete in the truck, out of the truck, toting them into the back yard, lifting again to dump in the mixer. Only used 14 bags. 5 X 5 slab, roughly 4 1/2 ~ 5 inches thick.

[Capt Jon]

Re: Capt Jon's Cob Oven

A quick dry stacking of the blocks to see that things will work prior to mortar.
The keen eye might notice that the walls are a rectangle as opposed to a square. I determined that I wanted a bigger opening for stacking my dry wood underneath. You?ll see how I deal with the extra space later. I had to use half blocks to get the desired results which ended up with some seams matching instead of being offset. I moved this around so that I did not have a seam that went continuous for more than two cores. I believe we will be alright though.
A quick note here...I don?t profess to know what I?m doing. This is a first time venture with no prior pizza cooking skills but, a little bit of construction skills. I?ve done a lot of Internet reading and have gleaned different info from different sources. The results will be a combination of different thoughts.

..and one more note. Yesterday was the first run of sampler pizzas in the oven. Wow, that was like nothing we have ever bought, even at a wood fired pizza places. Great crust, fresh ingredients.
Pictures will have to wait on that till I get the rest of the story out there?yep, it?s a teaser.

[Capt Jon]

Re: Capt Jon's Cob Oven

Now for the recessed area underneath the action area.
I haven?t run across this on anything I?ve looked at but, I decided to drill into my blocks and insert rebar into the blocks for the form. I?m sure it?s been done before by someone out there and I think it should hold up fine. I had a bundle of rebar ties somewhere but I couldn?t fine them and didn?t want to run all the way to the hardware store just for that.
Tie wraps and duct tape fix anything when you?re in a bind, right?
I felt it would hold just fine after the crete sets up.

Again, not wanting to go to the store, I found a piece of wafer board for the bottom of the form. Not ideal because it absorbs water. It turned out fine except for the fact that it swelled and wouldn?t come out. Doesn?t matter though, it?s underneath and can?t be seen. Maybe one day I?ll chip it out but, not too worried about it at this point. it's dry now and won't swell anymore.

OK, so I ended up with a rectangle area. Once I measured front to back, I marked off the overage on each side. Since the hot part of the oven really wasn?t going to sit on this area, I didn?t mix any vermiculite into the mix to square up the area. In retrospect, it wouldn?t have hurt anything and probably should have. The next build is always better?

[cobblerdave]

Re: Capt Jon's Cob Oven

Gudday
Welcome I'm interested to watch a cob build and especially something that doesn't involve to may trips to the store.
Regards dave

[Capt Jon]

Re: Capt Jon's Cob Oven

The picture of the sides filled in did not make onto the last post so, that's first.

So while the various previous things were drying or, other things were stopping me from full on engagement, I played with door ideas to cover the wood storage area. The results were assembled from a couple of new cedar fence boards. At a 1.78 each, doesn't get much cheaper than that. The wood to hold them together inside was just a few wooden stakes cut to size and screwed through from the front. Bit of sanding, polyurethane and cheap hinges. I think they turned out kinda nice. The metal angle iron supporting the opening will be painted black to match later.

I?m going to have to order the door pulls I want from the net. Can?t seem to find them at the box stores. I?m thinking a couple of Spanish style rings would look good. I?ve attached one magnetic latch to one door, have to do the other (mine masonry bit the dust doing the first one).
Since the second photo shows the coated doors and more, I have to jump forward and mention that I had some leftover slate tile from when I did the back porch. I think it looks good on there and you can see that I stucco?ed (yea, I make up words sometimes)as well. This will be stained red adobe once I?m through making a mess.

[Capt Jon]

Re: Capt Jon's Cob Oven

Gudday
Welcome I'm interested to watch a cob build and especially something that doesn't involve to may trips to the store.
Regards dave

Cheers, Dave.
You in particular have been a source of some great information. Having been a site stalker for a while, I couldn't give a proper thanks out to ya.
Now that I'm registered.. Thank you!

[Capt Jon]

Re: Capt Jon's Cob Oven

Time to talk bricks?
As with many of us, the missus had a keen eye on the costs going into this little venture. I try to save money anywhere I could as long as I felt it would hold up. The arch bricks are simple .63 cent bricks. I hope I don?t regret this later with the heat that I have noticed coming out of the oven (remember, I?m playing catch-up on the build story). I probably should have at least used refractory mortar.

The fire bricks, no compromise there. I paid 2.83 a brick and they were a booger to find here in the Houston area. Good for up to 3000 F. Of course the box store hands had no clue. Some were not even completely sure what a fire brick was, or refractory brick?
For the benefit of any in the area, Able Huber has them. They are in the area of Gus Wortham golf course close to downtown. Nice folks. The first time I went by to see what they had, they gave me four beaters for nothing so that I could do my measurement with bricks instead of gauging with a tape measure. Not great at answering their email but, they answer the phone. They said they were having some kind of email problems.
Refractory Materials, Ceramic Fiber, Plastics, Castables, 1-2-4, Refractory Products, lumnite cement

[stonecutter]

Re: Capt Jon's Cob Oven

I'll be watching this one...my current oven was going to be cob, but I went with brick. A cob oven will happen someday, possibly the spring.

[Capt Jon]

Re: Capt Jon's Cob Oven

Final installment for the evening...we're closer to bring you all up to where I am now.
Just a quick image of the fire bricks in to see how they set before layering in the insulating materials.
Stay tuned!

[Capt Jon]

Re: Capt Jon's Cob Oven

I'll be watching this one...my currant oven was going to be cob, but I went with brick. A cob oven will happen someday, possibly the spring.

I'm just the opposite, I wanted brick!
Cost/time/tool prohibited at this time.
I'm happy so far though. The pies yesterday turned out great for our first try and it's kinda rustic.

[stonecutter]

Re: Capt Jon's Cob Oven

Looking at your earlier pictures, it doesn't appear that you have any insulation under the floor brick, or room for insulation on the sides of the oven itself. This will be a big problem. Cob needs to be insulated the same as conventional refractory material.

[stonecutter]

Re: Capt Jon's Cob Oven

This book has a ton of useful info on cob/earth oven building, especially with inexpensive material. It's an interesting read too.

Build Your Own Earth Oven: A Low-Cost Wood-Fired Mud Oven, Simple Sourdough Bread, Perfect Loaves, 3rd Edition: Kiko Denzer, Hannah Field, Alan Scott: 9780967984674: Amazon.com: Books

[Tscarborough]

Re: Capt Jon's Cob Oven

You can do them like that, but laying them at a 45 degree angle to the opening of the oven is a much better way of doing it and worth the extra effort of cutting them. As laid, they will be constantly fighting your peel.

[Tscarborough]

Re: Capt Jon's Cob Oven

And FYI, there are 3 or 4 places in Houston that sell firebrick and refractory cement, although I won't vouch for their knowledge on the application for ovens.