Ben's Brick Oven in Berwick

[david s]

Re: Ben's Brick Oven in Berwick

I have a thermocouple set into the dome about halfway. it is convenient to read but I still prefer a thermometer that I place inside the oven which reads the air temp rather than the temp in the wall. These oven thermometers are quite cheap($8) and accurate. I make a minor alteration by attaching a larger base to it so it is less prone to falling over. Although it only reads to 300 C you can easily go off the scale. For high temps. I look at the oven, my watch and how long the semolina takes to go black.

[benguilford]

Re: Ben's Brick Oven in Berwick

I think when it actually comes to cooking a rather tasty pizza I will undoubtedly use the semolina method, but for me the thermocouples are a chance to indulge my nerdy engineering side, even if only for a short while. I plan on writing up a thermal analysis program to give the old grey matter a bit of a stretch, and use the actual oven as my 'test bed' to validate the results of the program. The idea being, you could plug in the dimensions of your oven, your local ambient temperature, the thickness (and thermal conductivity) of the insulation used under the floor and around the walls and the program could generate information such as time taken to cool down by a set amount, energy required to maintain a set temperature, time taken to reach steady state etc. It would certainly be a useful tool in the argument against using sand, broken glass and dead cats as insulation (I'm sure I am quoting someone from the forum here).

I acutally spoke to someone today who intended to use 50mm of packed sand on top of his concrete hearth slab, as the insulation for the cooking floor... I managed to talk him out of it thankfully!

[brickie in oz]

Re: Ben's Brick Oven in Berwick

It would certainly be a useful tool in the argument against using sand, broken glass and dead cats as insulation (I'm sure I am quoting someone from the forum here).

I cant wait for all the different builds with all the above mentioned......
How many dead cats do you require?

[david s]

Re: Ben's Brick Oven in Berwick

I wouldn't use sand for an insulator either, but suprisingly if you check the thermal conductivity of dry sand (0.15- 0.25 W/mK) it is actually pretty close to that of a 4:1 vermicrete at 0.16

[benguilford]

Re: Ben's Brick Oven in Berwick

Hi David, you're spot on, I was actually reading that very data last night. It would most likely be at the upper end of that scale due to the compaction of having the pizza oven resting on it, lets say a thermal conductivity of 0.2W/mK.

That is still 4 times higher than Calcium Silicate board at 0.05W/mK... I know what I'll be using!

[david s]

Re: Ben's Brick Oven in Berwick

I agree, but for folk who don't have access or can't afford the appropriate materials, I think it's probably a viable alternative. You can simply make the insulating layer thicker to achieve the same result.

[benguilford]

A Sudden Change of Plans

It has been a long, cold, wet and most of all BUSY winter for me, so the oven has been on hold for quite some time now. However, last Saturday we made the decision to put our house on the market, and the real estate agent wants to start bringing people through in the next couple of weeks! Initially he said one week, and I got an instant headache just thinking about what I had to do to get the place ready!

So, I have to finish the oven as quickly as possible, while still working full time and running a business. I will try to post my progress as I go, and I'll throw up some pics tomorrow. The phrase 'Panic Slowly' comes to mind...

[C5dad]

Re: Ben's Brick Oven in Berwick

That is a true bummer Ben. I know for me, I am looking at an overseas assignment which will have me gone a lot over the next few years - and I have yet to enclose the beast!

My suggestion is to have a brick cutting day to speed things up.

If you look at the pictures section, there are some old ovens from Italy in there that are not perfect but have stood the test of time. So build quickly, don't form fit every brick - use strait half bricks, and mud mud mud. And do use the templates/indispensable tool - life will be all the better.

And then with this learning experience over with, you are set for building your masterpiece!

Cheers Mate!

[benguilford]

Re: Ben's Brick Oven in Berwick

Well, it is done. The oven has been fired up now for two weeks, and is working like a charm. I don't think I have ever worked so hard in all my life!

I'm going to throw up my progress photos, I am looking forward to feedback, as I'm going to be building another one in my new house come November!

[benguilford]

Re: Ben's Brick Oven in Berwick

I enclosed the deck with tarps (classy, I know) to enable me to work day and night, rain or shine. I also bought myself an almost-new Bianco brick saw on eBay for a pretty good price. Couldn't have done without it, at least not in the time-frame I was trying to work to.

[benguilford]

Re: Ben's Brick Oven in Berwick

Floor laid out to test the location. Don't worry I haven't forgotten the insulation

The plastic drop sheets on the decking floor lasted all of 15 minutes, but I wish I had kept it covered with something as I had to spend hours scrubbing hardened mortar off it later on!

[benguilford]

Re: Ben's Brick Oven in Berwick

I cut the floor to fit inside the dome, allowing for the oven door reveal. Some tricky cuts involved. The blue tint on everything is from the tarps!

[benguilford]

Re: Ben's Brick Oven in Berwick

Cut the CalSil board to size (50mm thick) and levelled it with a thin layer of fireclay, using the notched trowel. I've allowed for a 20mm border of CalSil around the oven in case of weakness at the edges. The fireclay also just held everything in place while the floor went in.

[benguilford]

Re: Ben's Brick Oven in Berwick

Another layer of notched wet fireclay with some fine sand helped set the floor tiles. One thing I found was the because the CalSil board is so porous, as are the fire brick tiles, the moisture would get sucked right out of my fireclay mixture as I spread it onto the board, which made it too hard to really adjust the level of the tiles properly. To get around this, and to prevent too much water from leaching into the CalSil board, I put a skim coat of refractory mortar over the top of the board, so that it wouldn't suck the water out of my fireclay mixture. I found it worked well, but I'm sure there's a better way of doing it on the forum somewhere.

[benguilford]

Re: Ben's Brick Oven in Berwick

Progress! The half-soldier course is in, I used arch bricks cut in half for the first course and placed them with the cut side up, with the narrow face to the inside of the oven.







I used a slight tweak on the FB home brew refractory mortar mix; 2:2:1:1 (fireclay, fine sand, GP cement, lime) and I am really happy with it. Sets hard as a rock in about 3 days, and has a pot-life of at least 30 to 40 minutes. Good and smooth too, and no drying shrinkage providing I kept everything damp for at least two days after laying.