SC Chris's 42" WFO build

[SCChris]

Re: SC Chris's 42" WFO build

Sorry no pictures.

I now have the cement board completely fastened to the base and steel stud walls, no longer just tacked. The intermediate front and rear rafters have been have been fastened to the structure, tacked but primed. I decided on a 4 in 12 slope as that is what the tile roof dictates. I'll be running the roof past the front and back to provide more rain protection. The structure is now chocked full of insulation. The rock wool bats surround the dome, chimney and entry, to a minimum of 5 or so inches and what space was left in the structure is filled with fiberglass attic insulation. I'll be adding venting under the gable eaves to keep things nice and dry. These vents will also give me a way to verify no adverse heat buildup is created. For the roof sheeting, I’m using 1/2 exterior grade plywood. I'll cover this with self adhering 3' wide roll bitumen, rubber, roofing material. I’ll be weather tight at this point and next is the mission tile roof.

When I ran the 20.5 hour burn to 540, I found that heat coming out of the rock wool insulation was perceptible, but not concerning. I don't expect that heat buildup is going to be an issue within the structure with all of the insulation and the venting, but I'll be verifying heat transfer, hopefully the lack of it, when I go to full oven temp. Of course, I won’t button things up before this check.

I’ll have exterior temp numbers for posting next time.

Chris

[Dino_Pizza]

Re: SC Chris's 42" WFO build

Chris, your oven is looking good. Nice shape. It's easier to see what's going on with the siding and roof. Good choice with the sticky sided bitumen/rubber underlayment. Seems like good insurance. I appreciate all the work your doing in your slow oven cure. Can't wait to see the real fire in there! Mission tile roof sounds great. What's the siding going to be? Stucco? Great job.
-Dino

[geisen]

Re: SC Chris's 42" WFO build

Great build chris.
look forward to seeing the final exterior.

[SCChris]

Re: SC Chris's 42" WFO build

Status - November 23.

I had several guests coming for Saturday evening as pizza test subjects. As luck would have it Friday I came down with some sort of crud.. Sunday I felt a bit more normal and ran a combined cure / roast. I have been running up the temp by use of the propane torch and the last burn I had was a maximum of 550f, for several hours, at the end of 20+ hours of heat. Sunday I started the torch at 9am and built the temp for about 1.5 hours and then started adding almond wood. Once I had a good fire I removed the torch and built the temp to 350 at the top of the soldiers. Keeping the fire low, I added a package of beets to roast and 45 minutes later added a rib roast, foil on top, sitting on a bed of roasting vegetables. I rotated the roast twice and brought the internal temp to about 95. At this point I built the fire to a good blaze and browned the roast and pulled it at 129. Rested the roast for 20 minutes and sliced. The beef was spot on! The vegetable were underdone.. Lesson, Pre-heat the location the roasting pan is going to sit. Once the roast was out I added wood and built up to just shy of a full raging fire. After 20 minutes the dome was clear of soot and reading 850.. I sacrificed a quick margarita pizza to the oven, not quite sacrificed it looked like hell but tasted fine.

A great time was had by all!

Chris

PS 22 plus hours later and the interior dome bricks are 408 F. Wahooo!

PSS 46 plus hours and the interior is 230 F, The outside walls of the structure are 72 to 76 the outside of the door is 92 and the underside of the concrete floor, in the storage area is 96.. I still want to add a bit of insulation over the top, because I can, and tighten the door, because it needs to seal. Put in perspective it means if I do a pizza burn on Sunday I can add a pot to slow cook on Tuesday morning and come home to hot braised whatever that night.

PSSS 72 hours and 140f

[ThisOldGarageNJ]

Re: SC Chris's 42" WFO build

PS 22 plus hours later and the interior dome bricks are 408 F. Wahooo!

Wow,,, Very Impressive.. Sounds like you did a great job insulating

Good Luck

Mark

[SCChris]

Re: SC Chris's 42" WFO build

Thanks Mark! I'm also quite happy with the chimney. I was able to hold the SS chimney while the fire was running strong, est. 100 or so degrees. Additionally the entry area routed the smoke up and out the chimney as hoped.

Chris

PS the temp numbers for 46+ hours are added to the above post.

[ThisOldGarageNJ]

Re: SC Chris's 42" WFO build

I still want to add a bit of insulation over the top, because I can,

Im a true believer of you can never insulate too much... I may enclose my igloo in the spring and insulate some more after seeing your numbers..

Once again very impressive and congratulations..
Mark

[Dino_Pizza]

Re: SC Chris's 42" WFO build

Way to go Chris! Great oven temps 2 days later! It's good to know your vent/landing design is drawing air well. Don't forget that at 200 deg or even less your at perfect temp for drying out tomatoes and peppers to use on pizza's later. Then again, you already sound like quite the foodie with your oven.
So, whens the cassoulet? -Dino

[SCChris]

Re: SC Chris's 42" WFO build

Dino, As you know the weather round here has been a bit warm lately. When things cool down I'll give the Cassoulet a roll. The Mother In Law, MIL, flys in from the Loire region of France next month and if I'm lucky she'll be bringing Duck Confit and Goat cheese, "fat is flavor".

Chris

[pizza_bob]

Re: SC Chris's 42" WFO build

PS 22 plus hours later and the interior dome bricks are 408 F. Wahooo!

PSS 46 plus hours and the interior is 230 F, The outside walls of the structure are 72 to 76 the outside of the door is 92 and the underside of the concrete floor, in the storage area is 96.. I still want to add a bit of insulation over the top, because I can, and tighten the door, because it needs to seal. Put in perspective it means if I do a pizza burn on Sunday I can add a pot to slow cook on Tuesday morning and come home to hot braised whatever that night.

PSSS 72 hours and 140f

Chris,
Nice job with insulating your oven! I read back through your posts and all you used was 2" of insulating board?? And you're getting temps to hold that well?? That's great! I used 2.5" of Foamglas and 3.5" of vermicrete. I hope I can get results like that. What did you do around the dome?
Enjoy your cooking!

~Bob

[SCChris]

Re: SC Chris's 42" WFO build

What I did around the dome was use 2" Rockwool bats, sold as boards. When I bought the boards I thought I was buying bats. Bats are softer and more malleable. In the end I decided to see if I could wrap the dome with them. It was not easy and I still have areas I'm not happy with, but they work and do flex. If I were to do it again, I'd use the FB blankets to 2 inches or more and supplement this with the Rockwool and finally in the corners, furthest away from the heat, use fiberglass. I decided that the structure could be filled with insulation and the heat buildup that I saw during the cure fires didn't indicate that heat would be a problem for fiberglass in the corners, so I used the fiberglass and some minor steel framing, in the corners, as support for the Rockwool. As I button up the roof, I'll bring the Rockwool insulation to level with the top of the structure wall by laying the last boards on top. At the gable ends I'll be adding 3" vents. Moisture buildup is a greater threat to the roof, and steel studs, than heat, in my opinion. The Rockwool is something less than $40 a bundle and I've used 2, plus a bundle of fiberglass attic insulation, another $40 or so. I haven't decided yet if I'm going to use the vermiculite as loose fill to get things level for the last Rockwool layer or stuff chunks of Rockwool in the gaps. Rockwool has double the R-Value of the vermiculite, about the same as fiberglass. If you do the math, I’m already at $120 in insulation. I’ll use less wood in the end to heat and have more cooking days for this amount of wood.

The door also needs formalizing. I need to cut steel to fit both sides of the door and see how I can apply the fiberglass rope around the edge to seal the gap.

I'm really curious how long I can hold the temp above 250 F, 250 is the lower end of the cooking region for me. I start to wonder about bacteria growth inside food, below this temp. I'm also curious about the heat pushing through the floor. The same insulating board material that supports the floor is what the door is made of but the heat at 48 hours was about the same on the outside of the door as the underside of the slab. It'll be interesting to see how this changes as the slab dries out from additional fires. This same continued drying out of the dome should change temps within the structure. James's feeling is that the ovens take 8 or more “full temp” fires before they stabilize and heat quicker and fire up easier.

Time will tell and I'll have additional pictures of what I’ve done this weekend.

Chris

[SCChris]

Re: SC Chris's 42" WFO build

This weekend I had time to put the rafters and roof sheeting on. I decided that since I had the vermiculite, I'd use it to fill over and around the insulation. In the end I have somewhere around 12 inches of various insulation over the top of the dome and have most of the voids in the structure with some sort of insulation. Around the dome and entry, Rockwool, against the outside walls fiberglass and filling everything to close to level with the top plate vermiculite. I decided that I had 48 hours of cooking time before todays stuffing of loose Rockwool into voids and adding vermiculite, this is fine with me. I'd expect the cookable time to extend with the current re-organization of insulation and a tight fitting door.

I'll likley be extending the chimney a bit to get a bit of height over the planned mission tile roof. Although it isn't seen, then wood structure shown in the photo behind the small hardie backer panels, has been trimmed back to allow a minimum of 2" inches from the chimney. Also the steel wall structure terminates with a steel top plate and 2 2X4 pressure treated plates. These pressure treated plates are what the wood rafters attach to. What would normally be caled the celing joist are steel. No wood is closer than 14" inches from the dome or entry.

I also need to have a bit of flashing fabricated to surround the chimney and tie into the roof. The front back and sides of the roof sheet will have 2X6 facia board attached. Once this is attached I'll apply metal flashing where needed and apply self adhearing rubber flashing over this. At this point the oven will be water tight.

Next time I share photos I may have granite on the front of the oven and to the right side of the oven on the wall. This right side, will be a work area and off-table food storage.


Chris

[ThisOldGarageNJ]

Re: SC Chris's 42" WFO build

HI chris...
I think you got your insulation well covered... just one question... I think I see a fire extinguisher in the pic ??? were you getiing nervous

Cheers
Mark

[SCChris]

Re: SC Chris's 42" WFO build

Mark,

The fire extinguisher is for whatever code might exist in our area that mandates one and, more, for the nervous neighbor. After getting the tile roof on, I can?t think what might or could catch fire. The temps above the oven, on the insulation, have been in the 90s, and all this before the final tightening up of the insulation. Smoke out the front doesn?t seem to occur, other than a quick puff at lighting, so if I raise the chimney, it?ll be keep the neighbor happy. The side benefit might be that the smoke might not stain the tile roof and I might get better flow.

I cooked turkey for the Friday after Thanksgiving, it turned out great. I ran a fire during cooking and pre-heated where the roasting pan for the turkey would sit. I hadn?t anticipated the indirect heat coming off of the dome above the pan, so after a quick browning I added a foil. Yesterday I made soup with the bones.


Chris

[SCChris]

Re: SC Chris's 42" WFO build

Pizza.. On Sunday I made 4. 1 Magarita, 1 Pepperoni, and 2 Goat Cheese.. Yum!! I still need work on the crust and sauce, but it was good eats! The floor ran 850f for 3 out of 4 of the pizzas. As soon as the last pizza was out I buttoned the oven up. 24 hours later I pushed in a boned leg of lamb roast and the floor was still 500f, great roast. I let the heat brown the fat cap and then covered it with foil. It was pulled at 140f and rested for 20 min before slicing. Tonight, 48 hours after pizza the floor is 385f and I put a pan of apples to bake and the lamb revisited as hash. I'll be interested to see where the oven is tomorrow at 72 hours. I don't know I'll be able to wait till 72 hours to get the temp, I recieved flour and the Tuscan Grill from FG, and I'm itching to see how good the steak tastes cooked over almond wood coals.

At 72 hours 245f on the floor and 268f at the top of the dome. I put a fry pan of the leftover hash to warm up for dinner.

I'm amazed at how well these ovens can hold the heat..


Chris

Sorry no pictures this time.