32" Homebrew Cast, Metal Stand - Dallas, TX

[david s]

It is important that you now keep the casting moist for at least a week. This will enhance its strength.

[Kris S]

Looks much better now after patching up. I don't know if the voids themselves are bad for the oven integrity, don't think so.
Maybe you'll see some cracks forming along the voids later after a few firings, but they would've probably showed up anyways regardless of having a clean inside dome or not.
That's just my experience.

[loganc10]

Filling Voids with Slurry

Tried to fill in as much as the voids as possible at 48hrs after cast. I found this process to be probably the hardest part of build so far. Biggest issue is getting my arm, shoulder, and head up in the oven to reach the voids, and other difficulties were doing this at night with just a cheap flashlight.

I was able to get the left side of the oven fairly well patched up. I sieved around 1.5 cups of sand, 0.5 cups of other homebrew ingredients and mixed to a peanut butter consistency. I didn't have much luck using a spoon to force the slurry up into the voids, so I just used my fingers and smeared/forced it in as best as possible.

The right side of the oven still has/had some paper residue and had ran a bit out of time. I might continue tonight with scrubbing paper off, rewetting cast and filling any larger voids that remain.

[loganc10]

Internal Dome & Voids

With rest of sand and most of the paper peeled away, a lot more voids than I would've liked presented themselves. I think most of this stemmed from one or two of the homebrew batches being too dry.

At this point, it was 48hr after initial casting. With as hot as temps were the first 24hrs, I hope the internal dome still has enough moisture to properly bond with the slurry-coat.

[AndreasP]

Well, I didn't rake out the coals. Once I'm done making pizza I just spread out the coals and close the door.
After 12 hrs the oven is at about 450 F - 500F. Here is a graph from 4 different firings.

https://community.fornobravo.com/for...332#post446332

It really depends on how hot the oven was when I stopped cooking and for how long I have cooked.


Andreas

[Kris S]

How wide and tall is your opening? I think that the width makes a big difference as far as access is concerned.

I ended up making my dome opening 19" wide and 10" tall in the center, 8" on the side. 19" is on the wider side. Post#42 in my build thread has a comparison table if what I could find.

My entrance is really shallow, 8" .
I still need to add a 2" fascia that i have cast.

We have done pizza several times now and everything worked really well. Good access and with an insulated door l the oven is still at a out 500F the next morning.

Not sure if I would redo your base, then again, it wouldn't be that much work. I am sure others with a deeper gallery will chime in with their experience.

Wow really? Approx how many hours was that after raking out the coals? That sounds a lot, I've recently finally came round finsihing an insulated door, but after +/- 12 hrs the floor was only about 230F.
Need further testing though.

[Kris S]

Looking good!

[loganc10]

Remove sand & Damp Cure

Around 24 hours after finishing the cast I removed the previously applied plastic wrap and towels. Towels were still fairly damp (despite almost 100F heat here in Texas). I dug out most of the sand and styrofoam, then liberally sprayed/misted inside/outside with water, reapplied damp towels and plastic wrap.

I assume 24-48hrs is ideal time to patch up any internal voids, but I might not get to this until tonight or tomorrow night (which will be 48-72hrs after cast). As sealed off the damp towels and entrance is, I'm hoping it will still remain damp enough for good adhesion. Plus side is that it will be very humid/raining for next couple days, so easier to keep everything damp during curing in 90%+ humidity!

This weekend I will add the foam gallery mould and cast it. A little concerned I will not have enough clay for that process which would delay that a week.

[loganc10]

Dome Cast

I cut long triangle strips of light kraft paper and soaked in flour/water mixture. It was very windy putting the strips on, so needed to rig some tarps up to block the wind. Eventually with another set of hands, we were able to get everything laid on the dome then kept spraying with water to keep wet/damp.

Mixed homebrew in 5-6 gallon batches, taking around 4 total batches.

Covered in two layers of old damp bath towels and sealed with liberal amount of plastic wrap and tarp.

[loganc10]

Dome mould
I decided to cast in two separate parts - dome and gallery. Dome mould was made using lid of styrofoam cooler, some additional foam sheets, and sand with a little clay mixed it. I built a jig for the hemisphere, but it probably wasn't needed, patting with a trowel did a decent job at shaping and the jig was mostly for a radius spot-checking.

[loganc10]

AndreasP, good point. My oven will also be 19" wide and ~10" tall.

Including my 2" front face, I'll have a total of 14" for the landing/gallery. Searching around a bit more, it doesn't seem terribly uncommon to see 12-14" lengths around the forum, especially on the brick oven side of things.

I'll think about it a bit more and see if anyone else chimes in. I'm leaning towards no. While it would be pretty simple to cut the brick and insulation back the few inches, the concrete pad on the bottom would be more annoying/difficult needing to use an angle grinder.

[AndreasP]

How wide and tall is your opening? I think that the width makes a big difference as far as access is concerned.

I ended up making my dome opening 19" wide and 10" tall in the center, 8" on the side. 19" is on the wider side. Post#42 in my build thread has a comparison table if what I could find.

My entrance is really shallow, 8" .
I still need to add a 2" fascia that i have cast.

We have done pizza several times now and everything worked really well. Good access and with an insulated door l the oven is still at a out 500F the next morning.

Not sure if I would redo your base, then again, it wouldn't be that much work. I am sure others with a deeper gallery will chime in with their experience.

[loganc10]

Dome/Gallery Mold & Planning

Post #8 - #10 came as quick progress over the course of 3-4 days, though now I'm at a bit of a cross-roads and be procrastinating on the casting of the oven.

I laser-cut and will laminate pieces of 0.5" and 1" foam to create the gallery mold, then will create a sandcastle for the dome (with some styrofoam cooler/blocks to reduce amount of sand needed).

As I am dry-fitting the gallery mold, I'm concerned that it might be a bit longer than ideal. The wider section of the gallery (not including lip section) is currently 12" (30cm) long. I also plan on having a 2" thick cast facade on front as well, further increasing the depth.

So with that, I need to make the decision to trek on as is, or cut back the brick, insulation, and concrete pad 2-3 inches. I'd really prefer not to, but would like to get other's input on their lengths and if this would be a major or minor hinderance when working the oven. For what it's worth, I am taller at 6'2"/6'3"; so longer arms might help.

[loganc10]

Firebrick, Thermal Break, & Water Membrane

I found low-duty Whitacre Greer firebrick at a local mason supplier. I wasn't super happy with the condition of the bricks, there seemed to be a bit of thickness variance and some of the bricks had some pits or cracking; which I tried to pick around / cut out. Hopefully they will be suitable, and I'm just being overly anal.

I added a 45 degree cut-out/thermal break to the gallery bricks, then slid a left over piece of CalSil with the same angle into the void. Pretty happy with the result.

As shown in the pictures, I added some additional Redguard to the concrete pad and first layer of CalSil, I also put it under the gallery landing bricks; as documented by another user who reported it held up pretty well after a few years of use.

[loganc10]

CalSil Insulation

I used two layers of Thermo-1200 2" CalSil insulation, making sure each layer was oriented 90 degrees from the other.