New 36inch castable build in Brisbane

[stonecutter]

Re: New 36inch castable build in Brisbane

I have noticed that some people have inserted a heat break between the dome and flue gallery. So that they can maintain temperature without the "wick" effect sucking heat out of the dome. The whole flue structure is a heat sink, even if the door is on the oven.

Having said that, the flue is going to get hot with the fire going. Do you think its feasible to put two heat breaks in? One at the door, and one at the outer decorative arch. Strength may be an issue...

I have two breaks, the vent area is independent of the oven and the outer arch. The vent arch does not need to be tied into either of the latter sections, it does not strengthen the arch, because it is self supporting.

Correct that if you have a direct connection between the vent arch and the oven wall it will draw heat, and a break will help slow that action down...I doubt that a 1/2"-1" break will stop conductivity completely though. Loss of heat without a break between the oven and vent might not be measurable but it certainly won't hurt anything by doing it. The greatest benefit to a break (IMO) is between the outer arch and the vent walls, because almost all finish material does not have refractory qualities.

As far as the vent being a heat sink, my view is that as soon as the heat that is radiated by the fire and stored in the masonry of the oven passes through the oven opening, it doesn't matter if it is absorbed the vent or the flue...it is lost to the oven anyway.

[brissie]

Re: New 36inch castable build in Brisbane

Brissie,
Just had a second thought since you were asking about temp in the entry.
My heartbreak is actually between the flue gallery and the outer decorative arch. In that position vermicrete holds up ok , however if you put it between the dome and the flue gallery it is considerably hotter there. If it were me doing a vermicrete mix there I'd use some castable with the aggregate sieved out of it to mix with the vermiculite rather than using a Portland cement mix.
Dave

I have noticed that some people have inserted a heat break between the dome and flue gallery. So that they can maintain temperature without the "wick" effect sucking heat out of the dome. The whole flue structure is a heat sink, even if the door is on the oven.

Having said that, the flue is going to get hot with the fire going. Do you think its feasible to put two heat breaks in? One at the door, and one at the outer decorative arch. Strength may be an issue...

[brissie]

Re: New 36inch castable build in Brisbane

Mikku,

I am just a guy that has used a lot of information from this great site. It's the people who support the forum, and answer questions, and been around a long time that have made this site what it is.

It don't matter how fast you can make an oven. As long as you have fun. And I am having fun, and don't mind sharing the build. I hope people like it. I think its all about sharing, not enough of this these days.

Me - I am the guy in the middle, flanked by my son and neighbour. Who may be looking at building an oven also.

[david s]

Re: New 36inch castable build in Brisbane

All sound s good. I use vermicrete for the heatbreak gap too. I use 5:1 so it's got a bit more strength and holds together better than a lean mix. I use around a 10mm gap If you stuff some tissues in the gap at the top from underneath it will prevent the stuff from falling through until it has set. Get a thin stick and just compress the stuff in until it's full.

Brissie,
Just had a second thought since you were asking about temp in the entry.
My heartbreak is actually between the flue gallery and the outer decorative arch. In that position vermicrete holds up ok , however if you put it between the dome and the flue gallery it is considerably hotter there. If it were me doing a vermicrete mix there I'd use some castable with the aggregate sieved out of it to mix with the vermiculite rather than using a Portland cement mix.
Dave

[david s]

Re: New 36inch castable build in Brisbane

I have a question.

How hot does the flue assembly get towards the front and up say 200 mm?

The reason is I would like to put some light into the oven, for lighting the fire at night etc. I have read that it can be quite dark, and need a touch. I was thinking of using light - pipe, technology to relocate the light source away from heat. I would think heat resistant items, like either glass fibre bundles or silicone rubber tube, may work. Its just an idea I am tossing around. It may be easier to just use a touch.

Generally the entry stays black,ie the soot doesn't burn off there, so it's below about 300 C. If you have a fire going in the oven you don't need a light.

[stonecutter]

Re: New 36inch castable build in Brisbane

Why go through the motions of a bunch of useless chatter to get to the pro level!

That's why it doesn't matter......

[mikku]

Re: New 36inch castable build in Brisbane

15 hits! Lets make you a Il Pizzaiolo or whatever Forno Bravo calls the top --big number count guys! Why go through the motions of a bunch of useless chatter to get to the pro level!

[mikku]

Re: New 36inch castable build in Brisbane

Hey! You are really not a newbie to this type of work!

You have the whole thing down pat before you even proceed even 1mm!
It is nice to see a pro do his thing! You ask questions but you already know the answers a head of time!

You should do a video and put it on YouTube for this build! I am sure it would get a million hits!

Welcome aboard, I am sure you have a whole lot of things that you can add to this forum!

In the photos of the pouring of the base, which gentleman are you? Another geezer like me with a whole lot of history attached to his resume I would guess!

[brissie]

Re: New 36inch castable build in Brisbane

I have a question.

How hot does the flue assembly get towards the front and up say 200 mm?

The reason is I would like to put some light into the oven, for lighting the fire at night etc. I have read that it can be quite dark, and need a touch. I was thinking of using light - pipe, technology to relocate the light source away from heat. I would think heat resistant items, like either glass fibre bundles or silicone rubber tube, may work. Its just an idea I am tossing around. It may be easier to just use a touch.

[david s]

Re: New 36inch castable build in Brisbane

All sound s good. I use vermicrete for the heatbreak gap too. I use 5:1 so it's got a bit more strength and holds together better than a lean mix. I use around a 10mm gap If you stuff some tissues in the gap at the top from underneath it will prevent the stuff from falling through until it has set. Get a thin stick and just compress the stuff in until it's full.

[brissie]

Re: New 36inch castable build in Brisbane

David s, thanks for the encouragement, and yes It has been going well. I started 3 weekends ago.

Weekend time line:
Week 1) Dug the hole in the ground placed crusher dust, and poured the slab, stared the block base.
Week 2) Finished block base. During the next week added hebel boards for the top.
week 3) Completed oven dome and flue structure.

I was a Plumber, but left the trade 20 years ago. Trade skills help for sure. Being able to work with concrete, timber, and metals is handy.

I agree, if you take the brick route, its going to take a much longer time. Plus you need a proper brick saw for a considerable time. I purchased a small wet cut tile cutter, does 33 mm just enough to cut through a concrete block, and it worked okay for this project. You couldn't get away with tile cutter doing a full oven in bricks.

As for the insulation, I have 50mm Calcium Silicate board for the base, 7.2 meters x 600 x 25mm CF blanket, ad 3 100 litre bags of grade 3 vermiculite.

I plan on putting a gap between the dome and flue structure. I was planning on 10 or 15 mm gap using a vermiculite 5 to 1 or 8 to 1 mix between. Do you think this is workable? I will also cut a inverted V shape in the hearth doorway, with 2mm gap and the lower V filled with 10:1 vermiculite.

[david s]

Re: New 36inch castable build in Brisbane

Just checked the date when you broke ground, only ten days ago and you have the stand, oven and entry finished already. Brick builders seem to take months to get to this point.You are doing really well for your first oven.

How do you plan on insulating it?

[david s]

Re: New 36inch castable build in Brisbane

Yep, that's it. You've done well. I see how you've been able to keep the flue gallery nice and shallow. You will thank yourself for this when working the oven. Folk who make theirs from brick are unable to get it so shallow.They also take way longer to construct it being unable to create compound curves.

[brissie]

Re: New 36inch castable build in Brisbane

Cast the flue assembly. Used 1.5 bags of castable.

[oasiscdm]

Re: New 36inch castable build in Brisbane

. The needles make placement by hand more tricky. I often get stuck by one or two. You learn to handle the stuff with care.

I was thinking about that ouch