Oven Build in Spring

[cbailey]

JR, I hadn't read this thread. I searched the Forum for "door" and "oven door", but didn't get a result. I appreciate the help.

Russell, thanks for the help. I don't have a plasma cutter or welder, so buying those tools would end up right next to my biscuit cutter...not used and collecting dust. I like the idea of SS, but haven't decided yet.

What I get from the threads is that most have used 0.060" stock. So, about 1/16 inch.

Thanks!

[UtahBeehiver]

SS is preferred due to the lower Thermal Conductivity factor (K), SS= 14, Carbon Steel - 54, Aluminum = 237, Wood < 1 (but you are limited to lower temperatures with this material). Heavier the gauge, the heavier the oven. I would chose the lightest gauge that can be welded without warping.

[JRPizza]

Did you read the door thread yet?
https://community.fornobravo.com/for...ur-door-thread

[cbailey]

I have a quick question to the forum brain trust: UtahBeehiver, david s, SableSprings, JR Pizza, etc. I met with a fabricator to build a door. What is your recommendation for the gauge/thickness of steel? I don't want it too flimsy, then again I don't want it too heavy. Stainless is preferred, but might go with carbon steel.

Thanks in advance!

Cory

[cbailey]

I had a target temperature last evening of 700f. I reached it over a 4 hour period with peaks of 800f. I looked a little silly sitting in front of the oven watching it intently as i was trying to control temperatures. But with a cigar and a little wine I decided I had watched less interesting shows on TV!

As I often do, I referred back to the original Pompeii Oven build instructions. In the "Curing" section it indicates you're basically done curing if you maintain temps of 500 degrees for 10 (hopefully cumulative) hours. If so, I should be safe in applying render over the blanketed dome. I'm anxious to crank up the temps to watch the dome clear, but i would like to get the dome sealed ASAP. It rains too often here.

I'll include a vent on the top of the dome to allow an avenue for moisture to escape.

[cbailey]

David - Again, thank you for your advice. My Italian in-laws are in town and are both fascinated and excited about what we can cook in the oven. They talk about a Tuscan style bread that is getting more difficult to find, even in Rome. It would be great if I could recreate their memories.

Jay - Thank you for the kind words. But, I have to admit, most of my ideas were unabashedly copied from others on this forum. There are too many to name, many who have helped me and posted on my thread, many threads I have followed without communicating with the builders. There are some very talented people here, all more than willing to help us Newbies.

I'll be following your build. Best of luck

Cory

[terratree]

Hi Cory,

Your build post has helped me a lot, so thanks.

I'm a long way behind you but your pics/questions/solutions from the forum - have been very useful.

Very nice oven you have !

Cheers

Jay

[david s]

That sounds about right. Even a slight crack around an oven door will leak a substantial amount of heat. Italians used to use some left over bread dough to jam around the usually wooden oven door that had been soaked in a bucket of water to reduce charring. Or alternatively screwed up wet newspaper. I use a similar principle for my kiln, but use a 50/50 mix of sand and clay to seal around the door. For my ovens I use a wooden door which I like the look of but it’s faced with a cast insulating panel to protect the timber and it sits nicely against the flat cast surface of the front of the flue gallery. I think there are a number of solutions, just do what works for you.

[cbailey]

Thanks David! I have a 1.25 inch reveal, but the sides are straight. The 36 inch dome arch is the standard 12 inches high by 19 inches. So I would expect vertical expansion of approximately 1/8 inch and horizontally about 3/16th inch? To be safe 1/4 inch vertically and 3/8 inch horizontally should be good?

I fired the dome to 600f with peaks to 700. I haven't seen or heard any cracks yet. I'll target 700 tomorrow.

[david s]

The thermal expansion is around 1%. This is why it’s best to have a rebate that the door can sit against. For my first oven I had a tapered entry and the door was also tapered. If left in place the oven contracted hard against the door and made it really hard to get out, not a good plan.

[cbailey]

By the way Mike, I really like your build. As I mentioned before, I want to use used brick for the landing area and decorative arch. After apply the stucco/render to the dome I want to use a used thin brick to cover. A little ironic to recreate the build now that it is covered up. The bull nose on your landing area looks great.

thanks for the ideas!

Cory

[cbailey]

I completed putting chicken wire over the blanket on the dome. I was able to get the oven up to a sustained average (a bit of an oxymoron) of 500f for four hours. I would love to be able to keep the elevated temps over night, which means, I need to get after a door. Various threads recommend using the dome template and vent arch template as a guide. Of course, if I have the door fabricated to the exact dimensions the expansion of the metal due to heat would result in a stuck door.

How much expansion should I expect?

[cbailey]

I appreciate the compliment Mike, and the advice. I've used Tapcons around the base of the dome and wired the 3 inches of blanket down. I'm in the process of covering with chicken wire. I'll use stucco/render over the dome.

My plan is to make a landing and decorative arch out of used brick. It will look great, but I hate to cover up all the work that went into the vent arch. Oh well, I'll keep the pictures. I like the idea that the blanket will wedge into the gap. I really don't want to drill into the arch bricks. I've used lead anchors a lot in the past. There still is outward pressure on the brick. The left side of my brain tells me there is plenty of strength. The right side is telling me it could break! I think I'll try refractory caulk as make-shift adhesive. The render should hold everything in place.

I'm shooting for 500 degrees this evening while i finish with the chicken wire. There is a small chance for rain this evening (it's been a very wet winter), but the following 3 days with 0% chance of rain. At least I can get some work done in the evenings. Rain is forecasted for the weekend, so it will be a challenge to keep the blanket dry while reaching respectable temps.

Cory

[SableSprings]

I am uncertain how I want to fasten the insulation on the arch. I am afraid of using Tapcon screws or anchors for fear of breaking an arch brick. What about using high temperature sealant as an adhesive?

You've done a great job on this Cory. How are you planning to finish the outside of the dome? Stucco/render? Brick/stone facade? If you are going to do a stucco/render on the outside, having some sort of base wire can be pretty helpful. Many have used chicken wire, perlcrete or vermicrete (to provide better shaping), then the final finish coats (which are pretty thin). Since you have some top slab space available on both sides of the arch, you could use a couple tapcons to tie down some chicken wire at the base and then at the top a piece of wire behind the chimney to the other side. That would secure it enough to set the render in place. David S has just gone with adding fibers to the render for internal matrix support instead of chicken wire (if memory serves me correctly).

If you use a brick/stone facade, then you won't need to hold the batting in place...it will just sit in the gap between your arch and the facade arch.

Since the insulation doesn't need to extend all the way to the front arch face, you're simply looking at making the oven entry look good at this point. Based on the space you have, I think i'd just be setting bricks at slight angle from the front to the back on the sides with a little shave on the front edge to be flush. That would give a nice little flare into your dome finish. I hope that makes sense or at least gives you some options for consideration.

I agree about using "big tapcons" into brick (a little scary...no doubt), but they do make some pretty small "lead" plugs that also would do the job. You drill a small hole into the brick, tap the plug into the hole and then you can screw into the soft plug metal with a regular flathead screw to secure wire. I did this to make a rack to hold my peel and blow stick on the sides of my oven's brick facade. Pictures of the facade and peel resting on L-shaped screws plugged into brick/mortar are shown below.

[cbailey]

Started on the insulation. Curing fire at 400 degrees. Tomorrow I might boost to 500.

I am uncertain how I want to fasten the insulation on the arch. I am afraid of using Tapcon screws or anchors for fear of breaking an arch brick. What about using high temperature sealant as an adhesive?