32 Inch Pompeii in Northern California

[UtahBeehiver]

Re: 32 Inch Pompeii in Northern California

Congrats on the first fires. That is alot of "good" wood!

[boerwarrior]

Re: 32 Inch Pompeii in Northern California

Thanks Calisdad and Dave!!

I will go slow on the curing. I know the plans say to build fires to keep the temp at 300 degrees for quite a long time. I'm going to go a bit slower than that and build small fires every evening for at least a week. I had a massive oak tree fall down on my property a fews years ago - so I have enough firewood to last a very long time!

[cobblerdave]

Re: 32 Inch Pompeii in Northern California

Gudday Neil
Congrats ! Isn't a bit of a thrill to see the oven breath. Your right , there is always a bit of doubt that this thing will work. But to see that smoke condence into a flat cloud and float out the entrance. It always amazes me how the ovens breaths. Go slow on the fires your oven dome would be dry witch is an advantage drying and curing are two distinct things.
Regards dave

[Calisdad]

Re: 32 Inch Pompeii in Northern California

Kudos Neil!

Thanks for posting as I'm making entry arch forms as we speak and just want to know where I'm going before I get there. We can follow all the plans in the world but until we actually test the finished product we don't 'know' for sure. Looks great!

Enjoy-
Calisdad

[boerwarrior]

Re: 32 Inch Pompeii in Northern California

FIRST FIRE!!!!

I followed the discussion about reinforcing cladding and searched the site for all the comments I could find, and my conclusion is that there doesn't seem to be alignment on whether or not reinforcing is necessary.

I have a small oven (32") and I am also a little concerned about adding too much additional thermal mass. So I have decided for now not to add any further cladding.

My dome has been curing for two weeks.. so I thought what the heck I will make my first (small) fire!

I used oak kindling and I think it was a success! I got the internal dome temperature to around 200 degrees Fahrenheit which I think is about right for the first few curing fires.

But the best news is that the air flow and smoke ventilation looks perfect!

The fire had no problem getting oxygen and almost all the smoke went up and out of the chimney vent. Phew!!!

Still lots to do but this feels like another big milestone!

Neil

[boerwarrior]

Re: 32 Inch Pompeii in Northern California

good point K79, thanks!

I am about 25% of the oven opening. But then it narrows down to the 6" diameter SS pipe which is 28 square inches or 17% of the oven opening. My main concern was not constricting the flow before I hit the chimney pipe. I read on the forum that some others had issues with "constricted air flow."

I hope I got this right!

[K79]

Re: 32 Inch Pompeii in Northern California

While the reinforcing cladding discussion continues, I decided to complete my outer arch and chimney vent.

Actually it is more accurate to say: the first outer arch - because there is a decorative one that will be placed outside the first one. Knowing this I didn't worry too much about getting the mortar joints symmetrical and identical in width (as you can see!).

I am pretty pleased with the way the reveal ended up - it will make a nice seal for my door.

I ended up making the chimney vent a little smaller than planned because I wanted to have more of a 'flange' to rest the Duravent SS vent on. So the vent opening is about 6.5 inches by 6.5 inches square - still a lot bigger in area than the Duravent 6" diameter chimney.

I have keystones at the front and back of the vent opening and everything feels locked in solid. Also my angle iron buttresses seem to be working well.

Next step is completing the flat platform to rest the Duravent flange on top of.

Looking good. One thing about your vent opening. The restrictions on that as far as I know is that the vent opening has to be 15% of your oven opening and not the chimney diameter. Your opening is just over 42sqin. Looks like that's plenty big enough based on the size of your oven entrance.

[boerwarrior]

Re: 32 Inch Pompeii in Northern California

While the reinforcing cladding discussion continues, I decided to complete my outer arch and chimney vent.

Actually it is more accurate to say: the first outer arch - because there is a decorative one that will be placed outside the first one. Knowing this I didn't worry too much about getting the mortar joints symmetrical and identical in width (as you can see!).

I am pretty pleased with the way the reveal ended up - it will make a nice seal for my door.

I ended up making the chimney vent a little smaller than planned because I wanted to have more of a 'flange' to rest the Duravent SS vent on. So the vent opening is about 6.5 inches by 6.5 inches square - still a lot bigger in area than the Duravent 6" diameter chimney.

I have keystones at the front and back of the vent opening and everything feels locked in solid. Also my angle iron buttresses seem to be working well.

Next step is completing the flat platform to rest the Duravent flange on top of.

[cobblerdave]

Re: 32 Inch Pompeii in Northern California

Gudday
Re-enforcing clading ? Sparging layer .... Yes do this to " lock the outer" of the dome . Then build you structure and just pour the dry insulation in
Regards dave

[K79]

Re: 32 Inch Pompeii in Northern California

Is this reinforcing cladding just for those that are going to stucco the dome? Since I'm doing a full enclosure is this a step that I don't need? Sorry to hijack...

[david s]

Re: 32 Inch Pompeii in Northern California

Can anyone else very briefly give a yes or no on the reinforcing cladding?

Yes, I do but I use steel fibres instead of chicken wire mainly because the chicken wire takes quite a bit of time to get into place. You only need to throw in the fibres on mixing. I also use polypropylene fibres in this layer to give moisture a pathway out.

[cobblerdave]

Re: 32 Inch Pompeii in Northern California

Gudday
My experience was very much as Steve's 1 in of mortar over the dome to smooth things out . 2 in of ceramic then chicken wire in preparation for pearlite cement . Then a massive lot of rain in what was to prove to be our biggest flood for over 100 yrs . Rockwool insulation over the ceramic proved to be the quik solution at the time and conditions . Chicken wire and a couple of Layers of just ordinary bag render to top it off . Textured acrylic paint over that. Proved to work for three yrs now. Yes I did get dome cracks at the union of dome and chimney but was simply solved with the cracks chased out with a diamond blade and filled with paintable silastic and painted again with the acrylic paint.
I have sincsje added a vent at the top to allow moisture to escape having discovered the dome provided enough protection from the elements the main thing you have to protect is the entranceway and those porus firebricks from the water. Its a direct pathway to you hearth and finally your dome insulation.
I have recently added a brick veneer finish .... Just cause I like the look .. And will protect that with a simple brick sealer.
I have always been determined to keep the dome look and am reluctant to add overhead roof or encase my dome in another structure.
Hope somthing of my experience helps
Regards dave

[Greenman]

Re: 32 Inch Pompeii in Northern California

For what it is worth - I had a light layer of mortar over the completed dome to smooth things out, I then put the Ceramic Fibre insulation over that, chicken wire next (to help hold the vermicrete) and then the vermicrete followed by a render layer. That was then sealed with a textured acrylic finish.

My thinking was that there was nothing to reinforce before the vermicrete and with the metal mesh outside the CF insulation it would be less exposed to the rapid temperature fluctuations. So far it has worked for me.

I live in the sub tropics and with no frost in winter and summer temps not much more than 36 C I don't have to consider the extreme seasonal variations that some do.

Hope that is some use to you. Some others may have a more seasoned experiential opinion.

Cheers ........... Steve

[Gulf]

Re: 32 Inch Pompeii in Northern California

Can anyone else very briefly give a yes or no on the reinforcing cladding?

I am probably not the one who should respond to this. But, since no one else has:.....I did not install reinforced cladding to the exterior of my firebrick dome. I did do that for my stucco layer, though.

My take on this is that soft steel and masonry expand and contract at comparable rates under natural conditions. That being weather related temperature changes. These are relatively slow changes in temp. When fire is introduced to the equation, the change is more acute, and the expansion rates are too far apart.

Hopefully, this bump will alert someone else who can Pie-R-Square this for you.

Just Sayin'

[K79]

Re: 32 Inch Pompeii in Northern California

well I wasn't.... but CoyoteVB has me wondering if I should!

Can anyone else very briefly give a yes or no on the reinforcing cladding?