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Making a mortar and pestle |
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Whether you are making a small mortar and pestle or a
large African style version, burning the mortar cup out using hot coals is
an effective method. Mortar and pestles are a very useful piece of
equipment for grinding down all kinds of seeds, and nuts. This method of
using hot coals to burn out a cup or bowl can be used for making all kinds
of other utensils. If you don't have a crook knife/ spoon knife then maybe
this is the answer.
A mortar cup with a rounded bottom will help coarsely
ground material to cycle its way into the centre. Whereas a flatter
bottomed mortar will help to stop material jumping out when being
vigorously pounded.
In this tutorial I am burning a deep mortar cup suitable
for grinding small grass seeds.
click images to enlarge |
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Start out with a fully seasoned hard wood log, I am using an Oak log, if
you wish to prepare food in your finished mortar. Remove the bark and make
it nice and round using a small sharp hatchet. Make sure the top and
bottom are cut nice and level.
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Using a knife make a small depression in the centre of the top surface.
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For this project there are two pieces of equipment you can easily fashion
to make your life a lot easier. The first is a hollow straw which is quite
vital for bowl burning projects like this. I made mine from a stem of
Elder. (Be aware that some people say Elder wood is mildly poisonous, I
advise not to be too concerned...) You will use this straw to blow air
directly at the hot coals to encourage fast burning and quicker progress.
The second tool is a pair of tweezers to make life easy when transferring
coals from the fire to your log. A small wedge bound between two flexible
pieces of flat wood does the job
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Start your fire and you are all ready to go
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Take some good coals from the fire and place in the
depression, now blow on them...easy
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Keep blowing air until you make your first good depression. You may notice
that progress will slow down due to an eventual build up of thick charred
wood. At this point remove the coals.
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Scrape out the build up of charcoal with a stick.
Then add more coals and continue to burn the mortar cup bigger.
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On a large project like this I decided to save my lungs a lot of effort
and make a pair of bellows. This is a much faster method if you have the
materials. The bellows can be made from some scrap plywood, and leather. I
guess heavy duty canvas or similar material could be used. For the pipe on
the end I started with a piece of bamboo but later changed this for a long
piece of copper pipe. staple and nail the whole thing together for a quick
but effective job. |
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Constant burning and scraping is the name of the game. Keep going until
the mortar cup is as big as you'd like |
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Some areas will probably burn faster than others
which creates thin and thick areas. You can protect the thin areas
from further burning by protecting them with clay.
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When the mortar cup is the desired depth and size
give it a good scrape out with a crook knife and give the outside a
final shape with a draw knife.
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The large pestle is easy enough to make. Take a similar hard wood stave,
thin it down in the middle, leave the bottom nice and hefty. Round the
grinding end off nicely with your knife. All ready to grind! |
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Selection of mortars. Smallest pairs up with a nice Quartzite stone that I
found in an arable field.
Have fun! |
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