Planning my 32" cast oven

[AndreasP]

Thanks, i guess that's what I will do then

[Gulf]

Filled the gap with CalSil and left the top 3/4 in empty. I will either fill it with vermicrete or just let it fill up with ash. Not sure it really makes a difference.

In my opinion it does. We know that hardwood ash is consumable, in at least small quantities

I used ceramic fiber for the bottom 1" of my floor heat break and let the top fill in with ash.

[AndreasP]

Just noticed this morning that the plate in front of the dome is not large enough. I only accounted for the 1 1/2" of rebate for the door to fit against, but not the part where the gallery abuts the dome. Nothing that can't be fixed with a bit of duct tape and a few screws.
The areas of the opening looks like it is going to take a lot of Homebrew. 1 1/2" for the rebate + 1 1/2" for the gallery to sit against.

[AndreasP]

The sand castle went well, but I used approx. 250 lbs of sand even though I used all the bricks and misc. shards that I could find to fill up the middle. I should have looked for more material to fill the center. It taks a LOT of sand.

[AndreasP]

Went ahead and cut a 45degree angle off the entry bricks. Unfortunately I had to do this with the angle grinder, since the wet saw didn't have a large enough blade to cut this angle. worked out OK.
Filled the gap with CalSil and left the top 3/4 in empty. I will either fill it with vermicrete or just let it fill up with ash. Not sure it really makes a difference.

[AndreasP]

Made some progress yesterday. Finished cutting my bricks and built the sand castle.
Used my template to mark the bricks and used a tile wet saw to cut them. Made the whole process much easier than using the angle grinder.

[AndreasP]

Had to look it up, I guess technically it's a beam compass. the nail and pencil are the trammel points. I didn't know one can actually buy the trammel points. Here is a link to a video with Adam Savage. Might help some others.

[hillscp]

Trammel Points

[AndreasP]

Finihsed cutting and laying down the insulation. Had to redo some of the cuts. It seems that the string i used to draw the circles was a bit too elastic. Circles ended up not being circular and about an inch to large in diameter.

Redrew all my templates using a stick, nail and hole for the pencil. Much better results.

On to cutting bricks and building the sand castle. Hopefully casting tomorrow.

[AndreasP]

Fox, thanks for your feedback. Yes, I am struggling a bit with deciding on the "perfect" door opening size. I have looked through the forum and it seems that different people used openings between 17" and 19". I also looked at some of the commercial ovens to see what people are doing.
One of my challenges is that the oven is in a corner, so I think a larger opening will make it easier to access the inside (I have no access from the "hill" side), but I don't want to compromise performance.

Here is a table of what I think found:

	oven internal diameter	door width	door height	door recess
Mullster	32	18	10
Ronstarch	29	17
Kris S	28	19
Sergetania	30	19
Nick JC	32	17.7	9.86
Melbourne fire brick company	33.5	17.7	10.4	0.8
Brickwoodovens Cupola 28	28	18	8 side 10 middle	1.5
Brickwoodovens	36	18	8 side 10 middle	1.5
Forno Bravo Casa 32	32	17	10 center	1.5

[fox]

Re the door opening size… I think 17” is a more standard size for a 32” dome whether or not a 19” opening will make much difference I cant say.
You will loose a bit of mass and it may look slightly out of proportion and there may be some form of performance diference compared to a 17” opening but it has been mentioned on this forum that the opening width can be variable size…. However I dont know how much actual testing has been done?

[AndreasP]

CoastalPizza, thanks for your response. Luckily we don't often get rain storms like that in Southern California. I am more worried about several months of 99% humidity at night ant 70% during the day. Then again, the oven will be in the sun, so that should help drying it out.
I am planning on making some kind of cover for the complete oven, like a BBQ cover. Not sure yet where to get the material, but I am sure I can figure something out.

[CoastalPizza]

"Did you simply install the second vent so that it opens into the gallery of the oven below the chimney? Are you plugging the vents when you are not using the oven to avoid moisture from entering the insulation?"

Yes, that is exactly what I did. I used a well greased piece of PVC pipe (~1" dia.) inserted into the fiber insulation when I added the perlcrete and cast my inner arch. The pipe was pulled before casting the rest of the chimney gallery. That vent exits in the gallery below the chimney and is tilted down so rain will never flow into the insulation.

"We are fairly close to the ocean and often have 99% humidity in the early morning."

Same here -- the oven is about ~100' from the Intracoastal Waterway and about 1.5 mi. north of Bogue Inlet. I have a removable cover that goes onto the chimney plus a tilted-outward door in the arch that minimize rain getting into the oven. The vent at the top of the dome is plugged with a crankcase breather cap. I have found that I need to fire the oven early in the day to dry it out if it has been particularly wet. It takes me a couple of days of progressively hotter fires after a real dumper like the 34" of rain and 100 MPH wind we got during hurricane Florence in 2018.

[AndreasP]

Not sure why the image is so small in the post. I will attach it to this post. The file on my computer is 1600 x 1024 pixels and 500kB.

[AndreasP]

Trying to plan the form for the dome opening to get ready for casting the dome this weekend. I am thinking of doing an opening to the dome that is somewhat rectangular with a curved top. I think this will give me more space to place items into the dome.

For reference:

• Dome diameter - 32"
• Dome height - 16"

Opening to in the cast dome:

• Width 19" (is that too wide for this size dome?
• total height 10" (62% of dome height)
  • height of the rectangular section 8"
  • height of the curved top in the middle 2"

I am wondering if this design makes sense or if there are any issues with this. To interface the cast dome to the shape of the opening I will have to go away from the completely circular shape of the dome when it goes towards the opening.
am thinking of just using some pink foam insulation panels to create the form.