Monday, 16 December 2013

Building a wood fired oven - laying the hearth bricks

After a hard days work, it was time to unwind by laying a few of the hearth bricks for my wood fired oven.  It's not exactly the best time of year to be doing this, it is definitely winter here in Poland, dark by 4 PM and about -5 °C by then.

The mortar I will be using I have made by soaking some clay, dug from our garden, in water all day.  I turned the clay/water mixture a couple of time during the day and by evening it had soaked up lots of water.  

At first I though I would mix the clay smooth with a stick, but this soon proved very hard work, so I switched to a pain mixing attachment in a power drill.  To the clay, I then added an equal quantity of fine quarts sand and mixed for a few more minutes until smooth.  The result a very nice consistency of very sticky adobe mortar, minus the plant fibers.

To enable me to position my first brick correctly, first measured where the center of the hearth would be positioning a brick at the far end of the oven so that I could line up my first brick by siting down one edge lie a gun site.  Once this brick was strait and level the bricks on ether side were laid.

lining up the first brick
I'm trying to use a thin layer of the mortar and to enable me to adjust the brick as I set it, I am using a serated trowel to lay  ridges of mortar, much like you would do if you were laying tiles.  the bricks are placed with no mortar between them and and a tight together and as level as possible.  This was very slow going as the bricks are not very consistent in size or shape many do not have strait edges and have be rejected for use in a less critical part of the oven.

I think the first five bricks here have taken me more than an hour, but I'm not really worried how long this takes as long as its right.  These are the first few bricks I have ever laid, so at this point I'm hoping that I'll get better at it and things will start to move a little faster.  After about 20 bricks I'm starting to work out a few tricks, better at judging the amount or mortar, and better at tapping the brick in the correct position to steer it in the direction I want it to move.

Its getting very cold by this time, a quick cup of tea, and a few more bricks and I'm ready to pack it in for the night.

Two rows down, 4 more full rows and the ones around the ash slot.  A few more hours work and the hearth bricks will be laid.