Entrance dry? Chimney dry? Great! Let’s start building the next layer – the insulation layer.
What you’ll need:
- Some clay
- Some wood shavings
- Some water
- A bucket
- A wheelbarrow
- A spade
- A power drill and plaster mixer (optional)
The insulation layer complete.
First thing you are going to do is make a clay slip which is simply clay mixed with water. The simplest way to do this is to put some water in a bucket and slowly add chunks of clay, squashing, squeezing and mixing with your hands as you go. Alternatively you could add water to half a bucket of clay and leave it to soak for a couple of days. You could then squish-up the clay quite easily. You are aiming for a consistency similar to that of thin natural yogurt.
I spent quote a long time making my slip until I discovered a short-cut method using a drill and plaster mixer. It works really well but is very messy! Chuck your clay and water in a large bucket (or large bin) and blitz it with the mixer. Job done!
Next throw some wood shavings into a wheelbarrow. I bought a huge bag of wood shavings from a local pet shop and I still have three-quarters left (any takers?). Add some of the clay slip and mix well with a spade or get your hands dirty. The mixture should be wet enough to form “bricks” similar to those you made for the clay-sand layer.
Build up the insulation layer using exactly the same technique as before. Simple! Leave it to dry and then you can move on to the last step in the build – woo hoo!
hi as from my other posts i dont like the idear of wood insulation .ok my sugestion is that you use perlite (same stuff you bye at b&q in garden sectionused as plant feed ) lol ok you may laff but its got very good insulation properties (its used in construction to fire proof concrete)you can puddel it in to the clay as you do the sandit is water proof as well so mised with the clay may reduse the water damage in over wintering it also does not rot i saw it on another clay oven web site si i looked up the properties of it and i think it may be better than the wood shavings with the heat the ovens produse as with simons catching light lol
hi i have read the paper you quotied on wood shavings an i concur wood shavings are a good thermal heat barier (but and i quote the layer must be 310mm thick) thats a foot and 1 inch or there abouts wood shavings also suffer with damp if one gets wet and is touching another the prosess of osmoses becomes invilved where the water is transferd through capilary action to the next shaving this could cause a wet layer to form with in the clay next time the oven is lit after a break for winter say you are going to get a layer of steam prodused in the clay in my view causing a weak point in the oven as i said why use wood shavings
Well you don’t have to use wood shavings if you don’t like. All I can say is that it works! Have fun.
Simon