Karangi Dude's 48inch Oven

[Karangi Dude]

Re: Karangi Dude's 48inch Oven

After three days of burning the camphor wood and a couple of days to clean up and paint we finally got all the wood for the WFO stacked ready for winter.
There is plenty of dry wood, but there is also a lot of green wood that will nead a couple of years to dry out some I have not split up yet but I will get to that later.
Here is a couple of pics that show before and after the cleanup also a pic of the spotted gum offcuts

[brickie in oz]

Re: Karangi Dude's 48inch Oven

After three days of burning the camphor wood

Not in the oven I hope?
Camphor Laurel is toxic.

Camphor Laurel Menace

[UtahBeehiver]

Re: Karangi Dude's 48inch Oven

Hi Doug,

First of all your build was top notch. I am using your pioneering idea of a tapered arch in my build.

Since you placed quite a number of thermo couples in your build. Where would you find the most crucial place to install "two" thermo couples? I was thinking in the floor brick like you did at 10mm below the surface and the other in the dome but I wanted your input on what would be best.

Russell
Salt Lake City, UT

[Karangi Dude]

Re: Karangi Dude's 48inch Oven

Hi Russell,

Thanks for your kind words.
Russell, if you are going to connect one of the thermo couplings to a probe to measure the air temp then place that one just inside the door arch say halfway up and 10 or so inches away from the door arch, it will be out of the way and less likely to get damaged when loading the fire.
But if you want two for reading the brick temps, then I would put one opposite to where you will have your fire and about halfway up the dome wall (mine is on the right side as I move the fire to the left I find as a right hander it works better) and about 1/2'' from the inside surface.
The second one can go in the same brick but about 1/2'' from the outside surface, this one will help you learn how long it takes for saruration etc.
But if you do want to put the second one in the hearth then I would put it 1/2'' under the hearth brick about halfway between centre and the side wall opposite the side you will be moving the fire to, (mine are in the centre and I find they are to close to the fire so I am not getting the reading of the hearth where I cook my pizzas)
I also have an infrared thermometer that I use for taking readings of the wall and hearth surfaces.
Russell, having said all this I put thermo couplings in because a friend of mine is in the game and he got them at mates rates (very cheap) I put them in to satisfy my inquisitive nature to understand how these ovens work.
If you intend to do some baking then by far the most important thing is to be able to read the air temp.
When you are finished cooking pizza and put your door on the oven will start to equalise, it takes 3 to 4 hours to equalise so at this point whatever the air probe reads will actually be the equalised oven temp given the door is placed on and that the dome and the door are satisfactorily insulated. It does not matter what type of themometer so long as it protrudes into the oven a couple of inches, it can be in the door or in the oven wall it does the same thing measure the air temp.

I hope this helps.

[Bacterium]

Re: Karangi Dude's 48inch Oven

Doug,
Great build, as already echoed by others.
Must say I've gone over it a number of times, particularly the arch.

I'm still deciding on the insulating layer of the floor for my 2nd build. I noticed you used hebel? What has that been like for insulation? Just wondering how it compares to a cal sil board, sorry if I have missed this elsewhere?

[Karangi Dude]

Re: Karangi Dude's 48inch Oven

Hi Damon,

I acutally used insulating fire bricks they work really well but they are a bit expensive.
I don't think Hebel would work for this application at all.
Damon, I don't know how the cal sil would stack up against the insultion fire bricks.
If I was to build another oven I would go for 100mm vermacrete and 1 to 2 layers of 25mm cal sil

[UtahBeehiver]

Re: Karangi Dude's 48inch Oven

Doug,

Thank you for the detail information. You are a wealth of knowledge and I am glad I asked the expert. You have given me a lot of options. I have flexible thermocouples (good to 1900 F), so your suggestion of a air probe has me thinking. I have some 1/4" or 5/16" stainless steel tubing I could use as a probe and insert the thermocouple into the dome by the arch say a 1/2 to 1 cm. What do you think?

Thanks for your willingness to share.

Russell

[Bacterium]

Re: Karangi Dude's 48inch Oven

Doug,
Ahhh..... Insulating fire bricks, that makes sense. Just been chatting with a local supplier and leaning towards a couple layers of calsil might see if he can get me specs on both. Just doing the base wall at the moment on mine so plenty of time.

Good timing Russell on the thermocouple question, might look into that as well

[UtahBeehiver]

Re: Karangi Dude's 48inch Oven

Doug,

One more item. Just confirming on location of TC in hearth brick. 1/2 way from center to where you move fire "to"? or should it me "from" to measure the cooking surface of the pizza?

Thanks Again,

Russell

[UtahBeehiver]

Re: Karangi Dude's 48inch Oven

Hi Damon,

I am no expert by any sense of imagination but I did install 2" of foamglass which placed 1 1/2" CaSi boards on top. You can seem them in my build photos. Between the foam glass and CaSi cost was about $220 USD. I have a spec sheet on CaSi but not with me now can PDF it and send this evening if you want.

Russell

[Karangi Dude]

Re: Karangi Dude's 48inch Oven

Sorry Russell, I did not check what I wrote it did not make sence (I have corrected it now)
Russell, what I was saying is if you move your fire to the left, you would be cooking to the right, so place the TC halfway between centre and the right wall then it would be right under where you would be cooking pizza, but remember the reading from that TC would be a fair bit lower than the actual surface temp.
Russell, I have been thinking some more about having only 2 TCs and I guess I would go for putting two in the same brick of the dome wall. The reason is I believe that knowing the saturated temp of the oven will be more beneficial than other readings of the oven.
Faith covered this in a post just Yesterday here is the post;

Re: temperature monitoring

--------------------------------------------------------------------------------

Jlaw, for Pizza "heat soak" is not that important. You have a fire going in the oven so any energy used gets replaced with that fire. Granted you want a heated oven to do pizza. But the reality is that heat soak takes time that is determined by the transmitting properties of your oven walls and floor. So you can heat the interior to 1000 degrees but it will take the same amount of time to transfer that energy through the oven mass. But that 1000 degrees can tell you where the oven will equal out.

Now for baking bread heat soak is very important especially if you want to do multiple batches of bread. When you bake bread you take out the fire and coals and use only the stored energy. So the Heat Soak is what you use to bake and once that energy is used up you need to refire the oven if you want to bake more.

Hope that helps. Faith

Russell, also go back to my page 16 and check post #155 it covers saturation and equalising.

Russell, you can install an analog (mechanical) thermometer through the door it will give you the air temp and as I said it will also give you the fully equalised temp a few hours after the door is put on.

[Karangi Dude]

Re: Karangi Dude's 48inch Oven

Damon,
Even if you go for the cal sil board I would consider still putting some vermacrete down as well even if ist's only a couple of inches it is also pretty cheap, the more insulation the quicker the heat up and the longer the cool down.

[UtahBeehiver]

Re: Karangi Dude's 48inch Oven

Doug,

Thanks for the follow-up. I think I have it dialed in now. Going to install two TCs in dome wall as you suggested to determine saturation and check the floor temp with my infared gun which will get me in the ball park for cooking pizza.

ciao,

Russell

[cobblerdave]

Re: Karangi Dude's 48inch Oven

Doug,
Great build, as already echoed by others.
Must say I've gone over it a number of times, particularly the arch.

I'm still deciding on the insulating layer of the floor for my 2nd build. I noticed you used hebel? What has that been like for insulation? Just wondering how it compares to a cal sil board, sorry if I have missed this elsewhere?

Gudday
Sorry Doug but I beg to differ.
Damon I have used Hebel as the hearth insulation of my oven having built mine at the same time as Doug. Yes it proforms well with no problems. I use my oven about 3 out of every 4 weekends but cannot say how it would proform in say a commercial oven that was in use all the time however. Cost wise it would be probably cheaper to use Pearlite cement but the lot I had was free. I would recommend that anyone that used Hebel err to the side of caution and use it as a suplimentry insulation with a layer of pearlite or ceramic insulation on top.

Regards Dave

[Karangi Dude]

Re: Karangi Dude's 48inch Oven

G'day Dave,
No need to be sorry mate, I am unaware of hebels high heat resistance, I know hebel is aerated concrete and asumed it's use is for construction eg; wall panels, building blocks, homes etc.
Never to old to learn!!!