Ben's Brick Oven in Berwick

[brickie in oz]

Re: Ben's Brick Oven in Berwick

so I formed up the foundation slab and threw in some crushed Class 2 rock and gave it a good compacting with the whacker plate from Bunnings.

Totally unnecessary in Melbourne as we dont have great frosts or great movement of ground.

Also make sure you take out the broken bricks that are holding up the rio as they form weak points in the slab.

[david s]

Re: Ben's Brick Oven in Berwick

Ben, When you are building the stand, consider a side entry for the wood storage as it appears that your deck will go right up to the stand. Hot coals dropping into your wood storage can be a problem. A piece of alum. checkerboard screwed onto the deck below the entry is also a good plan.

[benguilford]

Re: Ben's Brick Oven in Berwick

Hi David,

I am planning on running the decking right up around the stand, and the checkerboard sounds like a plan. The last thing I want to do is burn my house down, my wife would frown upon that. I'd like to keep the woodpile in the front though, but I'm planning a smaller than normal storage area potentially with doors.

Thanks for the advice Brickie, I've actually already poured the foundation! (that's the next post coming through, I didn't want to do the full update in one huge post) and the bricks are there to ensure I maintain cover to the reinforcement. In terms of compressive strength the brick might be slightly lower than the surrounding concrete, but not by so much that they'd be a problem. I'd rather have them in there to keep the reo off the ground than not have them at all (I was too lazy to get some plastic bar-chairs from the construction site, and I figured at 225mm thick the strength of the foundation wasn't going to be an issue).

[brickie in oz]

Re: Ben's Brick Oven in Berwick

but not by so much that they'd be a problem. .

Too late now but they create cracking points in the slab, thats why they invented chairs.

[david s]

Re: Ben's Brick Oven in Berwick

Ben,
All you have to do is remove them as you go and pull the reo up into the centre of the slab.
Sorry, I see you've already poured.

[benguilford]

Re: Ben's Brick Oven in Berwick

The word 'darn' springs to mind. Ah well, all learnings for the next one I guess!

[benguilford]

Bringing me up to speed

OK, so while I have been working hard on my stand I have been terrible at posting my updates, so I am going to attempt to get my little thread all the way up to speed with where I am currently.

Having cured the foundation I bought myself some Besser blocks (again, found a bargain on eBay for $1.90 each and split it with Dave my neighbour).

I decided on having a small wood storage area at the front - the idea of having the whole area under the oven didn't appeal to me, as I knew the back half would end up becoming redback spider territory, and I have killed enough of those around my house already!

While I know I could dry-stack the blocks, I decided to make up some brickie mortar and set each one in place. I have been taking my time and loving the process so far, so I thought 'why rush it?'

It's not perfect, but nothing a good coat of render can't fix.

[benguilford]

Re: Ben's Brick Oven in Berwick

Once I finished the block wall I poured premixed concrete into every second void, each of which I reinforced with a piece of 20mm reo that I left protruding from the top of the blocks, to tie into the hearth slab.

I had access to a lot of 20mm reo through work, so I thought; 'Why not make a WFO that will double as a bomb shelter for my dogs should the need ever arise?'

I acknowledge my 20mm reo 'cage' looks ludicrous, but it's a bit of over-compensation for the fact that I will not have any angle iron supporting the opening over the wood pile area.

You can see me having a great time cutting and tying reo in the pics attached. I've even got my hardhat on.. Safety first!

[benguilford]

Re: Ben's Brick Oven in Berwick

From there it was on to forming up the sides of the hearth slab. What you can't see in the photos (because it went in at the last minute) is an electrical conduit that runs through the hearth slab from the back, along the side, coming up roughly were the arch will be. I saw somewhere in this forum that someone had installed high temperature lights into there vent pointing into the cooking are and it looked great, so I'm going to try for something similar. I also want to install a multitude of thermocouples to see how my oven performs later on..

[benguilford]

Re: Ben's Brick Oven in Berwick

Finally, they big day arrived! My good friend Jamin came to give me a hand pouring the slab, and the end result looks really good! I hired a pencil vibrator vibrate the concrete in my hearth slab, as I wanted it to get right into the corners of the formwork and to work its way around the large quantity of reo.

I have now stripped the formwork off the hearth slab, and I am ready to get stuck into the dome side of things. No rush though, I am enjoying myself tremendously and although a large number of my friends are leaning on me to get it done (for their own appetite-motivated reasons) I will continue to 'enjoy the process'. Finally, my thread is up to speed with my build.

I want to build my oven using the best quality materials possible; minimum 50mm of CalSil board (thinking about 100mm but it seems unnecessary, I'll run a thermal analysis on it and see if there's any real benefit), followed by 305x305x75mm 30% Alumina firebrick tiles cut to shape for the cooking floor.

Dome will be 30% Alumina firebricks, potentially tapered in one direction; ie. arch bricks cut in half. Then 100mm of Ceramic Fibre Blanket followed by 50mm or so of Vermiculite concrete, with a smooth rendered dome finish. (Hopefully it won't end up a lumpy mess)

I have access to a range of different fire bricks, at the moment I actually have a lot of brand new 42% Al arch bricks that I am selling (check ebay) but 30% alumina is more than enough, and I want to keep consistency in the material used for the dome and floor.

I'm thinking of putting a STACK of thermocouples into the oven as an experiment to plot the heat distribution over time, with thermocouples drilled into bricks at different depths, spaced around the oven, and through the insulation layers. Might yield some useful information for future builds? Has this already been done?

What thinkest thou? I am open to suggestions

[Vicbrickie]

Re: Ben's Brick Oven in Berwick

hey ben looks great! I thought my stand was a bomb shelter but if we go to war im coming to your place!! i'll be safer in yours ha ha!!

[benguilford]

Re: Ben's Brick Oven in Berwick

Thanks for the encouragement Doug!

You can't really see it but the step-up in the bottom of the wood pile is actually sloping toward the front of the oven, so if any water manages to get in there it'll drain right out rather than forming a puddle and soaking my carefully dried fire wood! I have been casting an eye over at Dave's timber... he'll happily donate some to a worthy cause at some stage down the track.

I must say I am well impressed with your thermocouple setup, that's just how I envisage doing it with my dome. I would love to have it link up to an old PC or something so I can plot temperature over time around the dome... It's the engineer in me! I can't help myself.
I am actually looking at importing a large number of quality Type K thermocouples so I should be able to get them at a reasonable price I hope.

[david s]

Re: Ben's Brick Oven in Berwick

Most people who put in lots of thermocouples find that after they get to "know" their ovens (say after 30 firings or so) they don't really use them. I find the stopwatch function on my watch is more useful. One hour for a roast, two for pizzas etc. Thermocouples do fail. I use an old anologue one that is not electronic, much more reliable. The best temp trick is the "semolina thrown on the floor trick" 3 secs to turn black 2 secs too hot 4secs too cold.

[benguilford]

Re: Ben's Brick Oven in Berwick

Hi David,

I know deep down you're 100% right... It's just the nerd in me wants to do a 'science experiment'.. Ever since I did thermal analysis with BAE Systems on some of their avionics electronics enclosures I have found it pretty fascinating, and I kinda wanna develop some basic software to analyse different oven designs to give the builders an idea of how they should perform before they build them... that's if I get the time!

[david s]

Re: Ben's Brick Oven in Berwick

Sounds good. Make sure you post your results so we can all benefit.