Outdoor Kitchen Build Norfolk

[ratboy]

I'd upload a screenshot but i cant!

[devontiger]

[ratboy]

OK, Im back!

So rain stopped play last week but at the weekend i did this!









This is the top of my fireplace cast from perlcrete

[ratboy]

And it fits in the finished fireplace like this!

[ratboy]

Now comes the exciting bit.

Build up one level over the fire place, get the lintels in and start thinking about my WFO!

[truckcab79]

Aug 7, 2018 17:54:47 GMT ratboy said:

Now comes the exciting bit.

Build up one level over the fire place, get the lintels in and start thinking about my WFO!

Very neat. Good to see progress.

[ratboy]

Cheers mate,

Not sure what WFO design im going to use yet.

Need to take the level up and see what area i have to work with bearing in mind i have to navigate round the flue for the fire.

Leaning towards a cast barrel as its looking like it will have plenty of depth but restricted width.

[ratboy]

Hi all, Back now with the fair weather!

This was where i got to last summer and now its time to finish!




I did a bit more this week.

I dropped the lintel for the fireplace in the hope it will aid in smoke collection/extraction. I have gone up one course and put in the WFO base support lintel in.



I had to devise a way to get the flue from the fireplace to the back wall so as not to encroach too much on the WFO, solution... Tumble dryer pipe encased in Pearlcrete! Ill take it out once its set!



Finished flue with added rebar for the WFO slab.



My reinforced base is in now and the flue exit is neatly to the back left.







Next up is a vermicrete/pearlcrete layer with storage heater bricks for the cooking surface.

So, some questions!

I am going to cast my WFO in this space, what would be the best material?

I was thinking plain old pearlite/portland mix to keep the weight down, the whole thing is going to be enclosed and back filled with vermiculite.

Can anyone see any drawbacks with this?

[downunderdave]

“Plain old perlite/Portland” mix is a poor choice IMO for two reasons. Firstly it will not provide the thermal mass required of a WFO. This means you will not be able to hold high temperatures in the dome easily because as soon as you let the fire die a little the temperature will drop quickly. You will also be unable to do any retained heat cooking because there will be insufficient thermal mass to hold the amount of heat required.
Secondly, the perlite/Portland mix is not very strong and will be subject to bumps and abrasions from tools and feeding wood into the oven. In addition Portland cement does not stand up to direct flame impingement so longevity is a big question.
A far better solution is to use a dense refractory castable or fire brick. As these are both expensive, if cost is an issue, a homemade castable can be mixed yourself using the homebrew (3 parts sand, one part each of Portland cement, hydrated lime and powdered clay by volume). The lime takes over from the Portland as it fails as the temperature rises and the clay provides some refractory characteristics. This brew is not quite as good as a proprietary dense castable refractory which uses calcium aluminate cement, but it’s streets ahead of Portland/perlite. Better to save your perlite to insulate over a dense material. If weight is an issue a dense castable with walls 50 mm thick is sufficient to provide required strength and the required thermal mass but way lighter than a 4” thick brick dome.

[ratboy]

Thanks for the advice Dave, i have gone with HomeBrew!

Cant wait for it to set and get the sand out!

Pics to follow..

[downunderdave]

Apr 19, 2019 19:00:59 GMT ratboy said:

Thanks for the advice Dave, i have gone with HomeBrew!

Cant wait for it to set and get the sand out!

Pics to follow..

Don’t be in too much of a rush. Anything made with Portland cement should be damp cured for at least a week to enhance strength.

[ratboy]

Ok, a bit more done.

2" pearlcrete slab in.





Sand out to reveal the oven.





Boxed in.




And started on the Flues.



One more course of blocks to go, backfill with vermiculite and fashion a roof.

The flues will be finished with stove pipe and rise about 200mm above the roof line, about 7ft in total.

Cut some slate to finish the woodstore but got rained off before i could bed it in, all floors will be finished like this.

[truckcab79]

Great to see this thread again. I Like your problem solving approach.

[oblertone]

Excellent progress, I can't wait to see how you'll 'mate' the two flues !

[dave36]

Apr 13, 2019 20:30:31 GMT downunderdave said:

“Plain old perlite/Portland” mix is a poor choice IMO for two reasons. Firstly it will not provide the thermal mass required of a WFO. This means you will not be able to hold high temperatures in the dome easily because as soon as you let the fire die a little the temperature will drop quickly. You will also be unable to do any retained heat cooking because there will be insufficient thermal mass to hold the amount of heat required.
Secondly, the perlite/Portland mix is not very strong and will be subject to bumps and abrasions from tools and feeding wood into the oven. In addition Portland cement does not stand up to direct flame impingement so longevity is a big question.
A far better solution is to use a dense refractory castable or fire brick. As these are both expensive, if cost is an issue, a homemade castable can be mixed yourself using the homebrew (3 parts sand, one part each of Portland cement, hydrated lime and powdered clay by volume). The lime takes over from the Portland as it fails as the temperature rises and the clay provides some refractory characteristics. This brew is not quite as good as a proprietary dense castable refractory which uses calcium aluminate cement, but it’s streets ahead of Portland/perlite. Better to save your perlite to insulate over a dense material. If weight is an issue a dense castable with walls 50 mm thick is sufficient to provide required strength and the required thermal mass but way lighter than a 4” thick brick dome.

Hi all.

Can I please resurrect this thread to ask if anyone has made home brew from clay instead of clay powered? I have some terracotta red clay left over the build and would prefer to avoid buying powdered unless I have to. I can cut it into very small pieces if particle size is important. Any experience or thoughts gratefully received.

Dave

Ps- if more background helps, I am building a new inner arch to push the door against. I doubt I can just use sand / clay mix as I suspect it would sag / take ages to dry ie I want something that I can cast (and would prefer not to spend a load of money on castable refractory plus postage).