starting my clay oven.....................or maybe not.

[Mickey-t]

Re: starting my clay oven.....................or maybe not.

That's good information mate.

Thank you very much.

I have three mates to help me when it comes to installing the clay, so hopefully time won't be an issue. I am the "guinnea pig" here, and they all want to install the same oven but were too scared to try it first.

Cheers

Mike

[Mickey-t]

Re: starting my clay oven.....................or maybe not.

Well folks

I have built my oven. I laid 100mm of vermicrete, then laid pavers on an ultra thin layer of sand. We formed the clay dome last weekend, and I have just tonight installed the vermicrete insulation layer on the dome.


I was a little worried, as in haste, I added sand to the vermiculite instead of cement!!

I then went over the first layer with a proper mix. Ie: perlite, cement and clay. I am hoping that it will be OK. I will apply another thin layer tomorrow and trowel it off as smoothly as possible, then weather seal it. It will be about 4" thick.

I have been "burning in" the oven for most of the week. Started with just newspaper, then kindling, then a bit more wood. I had a fire burning in the dome for about 4 hours yesterday (small fire), and all was looking good. I will continue to burn it in all weekend and early next week.

There are a few minor cracks in the dome, (already there before firing) but I am 100% confident that it is sound. The guy that sold me the clay told me that it WOULD crack, but it isn't a problem as long as the oven is insulated.

So I am looking forward to cooking pizzas for our friends next weekend. I wanted to get it finished for my birthday on 5th October, and it is all looking good so far....

I will try to get some photos on here soon.

Thanks again for your help everyone.

[Balthazar]

Re: starting my clay oven.....................or maybe not.

That guy was showing some sort of insulating material in the first 2 stands he displayed.

That white insulating material is Hebel Blocks, which is aerated concrete and has superb insulating characteristics. I'm currently using it as my insulating base.

I'm basing my design in the "Better Homes and Gardens" WFO, but making a few changes. For example, using refractory concrete rather than clay. More expensive, but less fiddly. My outer insulating later will be vermiculite with cement fondue.

[Balthazar]

Re: starting my clay oven.....................or maybe not.

That film clip and associated PDF from the "Better Homes and Gardens" website says to use "brickie's sand", but in the film clip he's using washed river sand, which is a very pale grey colour. Brickie's sand contains clay is is an orangey colour I believe?
Could someone clarify this?
Thanks

[Mickey-t]

Re: starting my clay oven.....................or maybe not.

Well,

I have cooked the first pizzas in my oven tonight, and they were GREAT!!

I thought I had removed ALL the moisture, but the very top of the dome and around the flue showed dampness as we were cooking. But, otherwise, all else was good.

The moisture was only in the insulation, and not actually in the clay. The oven reached 500*C, and pizzas were cooked in just over 2 min's.

With the left over dough, I experimented in cooking naan style bread, and it was excellent.

Overall, I am very, very happy with the oven and our friends that helped in the building process enjoyed the pizza, and are just as pleased.

I can see a busy few weeks ahead helping my mates build their ovens.

We finished cooking about 4 hours ago, and the oven is still H-O-T, so, obviously well insulated.

All is good in Perth, WA!

[Wood fired oven workshops]

Re: starting my clay oven.....................or maybe not.

Re Starting my clay oven.... or maybe not.
I'm the person behind the Low tech. oven as seen on the 'Better Homes and Garden TV Show' in Oz.
You saw 2 types of under floor materials.
The 1st one,seen in brief, was a layer of 'Hebel' blocks to prevent the heat escaping through the floor. Then you saw the packing of 200 mm of decomposed granite [packing gravel] in a 'well' in the oven base to act as a 'heat bank' to absorb the heat from the floor so that it 'gives back' once the fire is out or removed.
The untimate combination is to have a layer of insulation material down first [Hebel or Cal-Sil board or insulating bricks] then a decent depth of 'heat bank', then the oven floor.
You can see photos of some finished low tech. ovens at woodfiredovenworkshops.com

[Johnny the oven man]

Re: starting my clay oven.....................or maybe not.

Good to see you on this site Alan, when do the Tasmanian workshops start?

[Mickey-t]

Re: starting my clay oven.....................or maybe not.

Re Starting my clay oven.... or maybe not.
I'm the person behind the Low tech. oven as seen on the 'Better Homes and Garden TV Show' in Oz.
You saw 2 types of under floor materials.
The 1st one,seen in brief, was a layer of 'Hebel' blocks to prevent the heat escaping through the floor. Then you saw the packing of 200 mm of decomposed granite [packing gravel] in a 'well' in the oven base to act as a 'heat bank' to absorb the heat from the floor so that it 'gives back' once the fire is out or removed.
The untimate combination is to have a layer of insulation material down first [Hebel or Cal-Sil board or insulating bricks] then a decent depth of 'heat bank', then the oven floor.
You can see photos of some finished low tech. ovens at woodfiredovenworkshops.com

Yes it is great to see you here mate.

I, for one am extremely gratful to you for this oven. I enjoyed the project, and I very much enjoyed our first pizzas last Sunday. It also cooks great naan bread.

THANK YOU!!

[Balthazar]

Re: starting my clay oven.....................or maybe not.

I'd also like to thank you Alan. It was your design that first got me interested in building a WFO. I'm also using the BHG design, although just changing it slightly for where it goes in my courtyard, and using refractory materials from John, rather that the low-tech method.
BTW, is there something extra I need to know when using refractory cement rather than clay for the igloo?
Thanks

[Wood fired oven workshops]

Re: starting my clay oven.....................or maybe not.

Hi Balthazar,
I've found the addition of a couple of cup fulls of stainless steel 'needles' [those used in the furnace industry] to a bag of castable is a fantastic reinforcement that eliminates cracking, even on a large dome.
John from Refractory and Ceramics P/L has them, but he may already have sold you some.
Wood fired oven workshops

[Balthazar]

Re: starting my clay oven.....................or maybe not.

Hi Balthazar,
I've found the addition of a couple of cup fulls of stainless steel 'needles' [those used in the furnace industry] to a bag of castable is a fantastic reinforcement that eliminates cracking, even on a large dome.
John from Refractory and Ceramics P/L has them, but he may already have sold you some.
Wood fired oven workshops

Hi Alan. Yes, I've been to see John a few times already and I'm about to visit him again to purchase everything for the dome. Today I finished the cooking surface and surrounding pavers so I'm ready for the next stage. Hopefully I'll get to see John tomorrow
Have you got any idea of how many 25kg bags of refractory cement I'll need for the dome? It's the same size as your design on "Better Homes and Gardens"...or near enough.

Thanks

[Wood fired oven workshops]

Re: starting my clay oven.....................or maybe not.

For our workshop high tech ovens [about the same size as the BHG oven] we use about 8 bags of castable, then a full roll of blanket and a 'cap' of ordinary cement/sand/stone dust concrete to build that up to cover all of about 30 -50 mm. thick.
You will see some photos at Wood Fired Oven Workshops.

[Balthazar]

Re: starting my clay oven.....................or maybe not.

YIKES!!! 8 bags!!?? ($$$). How thick is the castable layer? I was going to go about 50mm thick? I also wasn't intending to go with the blanket. I was going to use Vermiculite with cement fondue mix straight over the castable to a thickness of about 75mm for the insulation layer. Would this still be ok? I'm pretty much following the BHG model, except with refractory materials.

[Wood fired oven workshops]

Re: starting my clay oven.....................or maybe not.

The 8 bags of castable should give you a 'hotface' coverage of 50-75 mm. but thicker better [$$$$].
Vermiculite is a good insulator but the insulation properties are diminished the more binder materials [fondu etc.] you add.
One advantage of 'ceramic blanket' is that it acts as a cushion between the hotface of the dome and the protective cap of concrete as an outer shell.
If the layers are all tight the expansion of the inner dome can 'shove' the outer layer into cracks.

[Balthazar]

Re: starting my clay oven.....................or maybe not.

Thanks Alan. I presume John sells the ceramic blankets? I'll call him tomorrow.
I was intending a 4:1 mix of vermiculite:fondue. Is this a good ratio if I do choose to go with it?