Soooo confused

[needy]

Hi Again

I had a idea in my head on how to build a clay oven but since joining this forum my head is in a spin,if i tell you my idea step by step could someone comment on if im doing the right thing please

Ok here goes :-

1:- Base
2:- Thermal blocks flat
3:- 2 or 3 courses face brick laid in square
4:- Infill square with wine bottles filled with clay topped of with fire bricks
5:- Dome of sand wrapped with wet news paper
6:- Cover with clay about 4" thick then slice opening with wire before dried (opening about 14"-16" wide)
7:- Leave to dry then remove sand and place tea lights in few days later
8:- Build arch
9:- Once fully dry was going to render outside with waterproofer then paint

I was NOT going to put a chimney in the oven or cover with a roof is that ok ??

How does that sound or am i off my head lol

P.S
Anyone know where a can get clay from im in Newport South Wales
Do you mix the clay with sand if so is it 50/50
Also after some fire bricks locally

Any info very welcome

Thanks

[dave36]

Although I'm only just started, your plan does sound about right to me and similar to my own- couple of differences-

- I'm building the arch and then extending the former up to the arch
- I'm doing a chimney, although to be honest, I'm not sure why it's needed!

Eitherway, small differences and I've read tonnes of guides and yours seems right to me.

Re clay- toppot supplies and Anglia clay do pizza over clay and deliver. Kilnlinings seem to the cheapest I can find for firebricks and deliver. Unfortunately, delivery costs are quite high (I can't even find these materials locally living is south London!)

Hope this helps,

D

[oblertone]

You both seem determined not to use a flue but don't say why; yes your respective domes will work without a flue, I used mine for a year before insulating it and adding the arch and flue. However, it works much better with one and is nicer to use as the flue helps the air flow in by extracting the exhaust and directing it away from the user.

As to leaving a bare clay dome without protection, please think again. Clay, and other materials used in a WFO should be considered mildly hydroscopic, that is if they are drier than the surrounding atmosphere they will attract water. In the uk you may well find that a clay oven will return to its natural state i.e. mud, if not protected.

Finally, a bare dome will cook pizza very well, what it won't do is allow cooking using retained heat as the exterior will act as a radiator. To retain the heat you need to insulate the dome, and that insulation needs to be protected from the elements, hence why most domes use the multilayer approach you'll see repeated in the build threads on here.

Hope this helps.

[needy]

Thanks Dave36 and Oblertone for the replys

A question to Oblertone as you can see i am a total novice can you answer me 2 questions please (or someone else who knows)

Regarding the flue i just thought a flue/chimney would defeat the object of keeping the oven warm as heat will escape through it 
Also i have seen pics of the clay dome being wrapped in rock wool insulation and held in place with mesh which then will allow a top coat of cement render with waterproofer to be applied....do you think that method is ok to insulate and weather proof the dome

Thanks Again

[awalker]

Sept 5, 2016 13:56:30 GMT needy said:

Thanks Dave36 and Oblertone for the replys

A question to Oblertone as you can see i am a total novice can you answer me 2 questions please (or someone else who knows)

Regarding the flue i just thought a flue/chimney would defeat the object of keeping the oven warm as heat will escape through it 
Also i have seen pics of the clay dome being wrapped in rock wool insulation and held in place with mesh which then will allow a top coat of cement render with waterproofer to be applied....do you think that method is ok to insulate and weather proof the dome

Thanks Again

Hi needy
The chimney is separate from the main done. Normally in the entrance/arch door way to the oven.

On the insulation anything will help. Not sure on render, never had any on my old clay oven. They are right mine did cry in the rain. Muddy tears :eek:

[chas]

Sept 5, 2016 14:42:44 GMT awalker said:

Sept 5, 2016 13:56:30 GMT needy said:

Thanks Dave36 and Oblertone for the replys

A question to Oblertone as you can see i am a total novice can you answer me 2 questions please (or someone else who knows)

Regarding the flue i just thought a flue/chimney would defeat the object of keeping the oven warm as heat will escape through it 
Also i have seen pics of the clay dome being wrapped in rock wool insulation and held in place with mesh which then will allow a top coat of cement render with waterproofer to be applied....do you think that method is ok to insulate and weather proof the dome

Thanks Again

Hi needy
The chimney is separate from the main done. Normally in the entrance/arch door way to the oven.

On the insulation anything will help. Not sure on render, never had any on my old clay oven. They are right mine did cry in the rain. Muddy tears :eek:

Just expand on that: the chimney is usually in the entrance, and a close-fitting, fire resistant 'door', pushed past it to seal the oven for long cooking. If you have an external door you can get much the same effect by capping the chimney to seal.
The blanket insulation you suggest should be fine, I'm sold on K-rend for weatherproofing: easier than conventional render and self-coloured.

Chas

[oblertone]

Needy, hopfully the responses above have answered your questions; I think the only concern with using rockwool as an insulator is its resistance to the temperatures it will experience on the outer surface of a clay dome, which will approach 500c. It can be a messy job which you don't want to do twice, so I'd recommend using a proprietary insulating blanket the first time around.

[curlygirl]

Sept 6, 2016 10:06:14 GMT oblertone said:

Needy, hopfully the responses above have answered your questions; I think the only concern with using rockwool as an insulator is its resistance to the temperatures it will experience on the outer surface of a clay dome, which will approach 500c. It can be a messy job which you don't want to do twice, so I'd recommend using a proprietary insulating blanket the first time around.

I'm really new to this so don't profess to be an expert. But I do love watching my fire burn inside the oven and hopefully my pizzas bubbling in the future - Im so proud of mine I just can't help it!! If you have no chimney you can't do this as smoke would be belching out the arch. We just stuck a bit of flue pipe in and slobbered a load of clay round it - really easy. Plan to make a wee damper to plug it with for the slow cooks.

[downunderdave]

Rockwool against the dome is fine. There's no way the outside of the dome would get to 500 C. One problem with the stuff is that it is quite loose so working another layer over or against it is difficult. Ceramic fibre blanket is much firmer. Another problem is that it does not cut as easily as ceramic fibre blanket. Also it is more water absorbant.
Instead of making a complex damper it is easier to cap the flue with an inverted terracotta flower pot saucer which can also be used to keep out the rain when the oven is not in use.

[needy]

Thank all for the replys
a question to downunderdave
if i use the ceramic fibre blanket can i wife mesh over the top of it and render over it with waterproofer to a finish
thanks

[chas]

Sept 15, 2016 15:15:16 GMT needy said:

Thank all for the replys
a question to downunderdave
if i use the ceramic fibre blanket can i wife mesh over the top of it and render over it with waterproofer to a finish
thanks

Since I happen to be here, Dave isn't - and think I know... yes.
Have a look at my 2nd sig link "retro fit insulation" below, it shows my journey through a reuctant afterthought.

Chas

ps unless 'wife mesh' isn't the typo I think it is...

[downunderdave]

Sept 15, 2016 15:15:16 GMT needy said:

Thank all for the replys
a question to downunderdave
if i use the ceramic fibre blanket can i wife mesh over the top of it and render over it with waterproofer to a finish
thanks

Yes you can, but it's best to drive out the water before you render over it with a waterproof render, otherwise you may lock in moisture= steam and cracking outer shell. Also a layer of vermicrete over the blanket can even out the lumps and bumps to give you a nice form and firmer surface to render on to. I don't bother with using chicken wire over the blanket, takes too much time, but place a layer of vermicrete straight over it. There are lots of ways to go.

getting your wife to do the work is a great idea, should be more of it.