Is fire clay can be available from the nature? As per manufacturers of fire clay it can not be selling in market. No worries about that to worrying this kind of situation. Close your eyes and think about this, give it a go several times. Think of a place outside where you saw mud of a lighter color.

It means a place with water soil erosion work going on. When wet, mud is soft and sticky without any organic matter in it. Not like a top soil, Never confuse these two. Mud can be found usually deeper below top soil. It’s everywhere around us but can not be seen until it’s uncovered.

You have to find direct where it is not mixed with sand or rocks, and remember the light color. You need to uncover a mud which has similar structure to the play dough. Fire clay shrinks about 10 to 15% after water dries out so take home an extra bucket more.

You can make a test if you like;

Stretch and flatten piece of the clay into 13cm or 5 inches long strip

With a sharp object make 2 marks in it – exact 10cm or 4inches between the marks

Leave the clay to dry

Re measure when dry to see the shrinkage difference

Some Potters still keep their own clay source spots as the world’s best kept secrets. Own sourcing was very common years ago but for sure it’s many artists’ hobby and pride not buying commercially packed modern clay bodies. It’s different however with quantity producing potters.

Lot’s of enthusiasts dig for the clay. Mix fire clay with sieved fine sand to make the top refractory mortar! Mix it with coarse river and make clay adobe tiles out of the stuff. Mixing send into wet clay by walking in it, or mixing sand with clay both in dry form and then adding water in, second example requires less effort and is much faster.

As these adobes dry, they shrink a bit and should be covered with plastic so the drying speed is slower, that prevents banding and cracking. More grog is added into the clay, for adobe tiles, less shrinkage and cracking.

Never add straw saw into body of mud bricks for creating wood fired oven dome, because it burn off just as organic material does. It’s being added into heat insulation only to create honeycomb like airy lightweight effect House building bricks are different to refractory application. Clay adobe and bricks must be dense and less porous, solid and heavy.

Cement is used only to make the mortar to dry faster, to set as you work to progress fast. Also experts fire clay manufacturers tell you that, no need for refractory cements everywhere, these are expensive and used by industries for theirs hi temps kilns and furnaces or for castables.

Source :

• http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it

More seasoned structures with load bearing bricks walls are regular in greater part country. While these thick bricks walls were regularly put on the inside, they were seldom insulated.

Old bricks walls are dubious to protect. Here's the reason: in the event that you insulated the wall on the inside, you'll make the bricks colder amid the winter. As we probably am aware from the psychometric outline, frosty blocks are constantly wetter than warm bricks.

When the walls is insulated, the getting away warmth that earlier went through the bricks is no more accessible to drive out the dampness. So your wet bricks stay wet for quite a while. Now and again, rehashed cycles of solidifying and defrosting can forever harm the bricks, making them go to pieces.

It's conceivable to use insulation brick which expanding on the inside.

If insulation bricks on the wall in interior can make the walls defenseless against stop/defrost harm, does that mean such walls ought to never be insulated? No. In any case, insulation bricks manufacturers and suppliers who need to insulate an old brick walls ought to continue circumspectly.

There are no basic dependable guidelines concerning surveying the defenselessness of a current brick building to stop/defrost harm. 

On the other hand, here are the most essential focuses to recall: 

• Most, yet not all, current brick structures can be securely protected on the inside. 

• The colder the atmosphere, the more prominent the danger of stop/defrost harm. 

• The thicker the protection, the more prominent the danger of
  
  stop/defrost harm. 

• The more rain that falls on the walls, the more prominent the danger of stop/defrost harm. 

• A few bricks are more powerless against stop/defrost harm than others; there are tests to figure out if you're building has great bricks or terrible bricks. 

• If you use insulation bricks on the wall inside of a brick building, the finishes of joists and bars that are installed in the outside walls can spoil. 

• The initial phase in evaluating the powerlessness of any brick building to stop/defrost harm is a site visit by a brilliant spectator. 

In the event that the majority of this sounds entangled and confounding, you can go for expert manufacturers and suppliers of insulation bricks for best way to proceed.