English subtitles for clip: File:Manufacture nationale de Sèvres Atelier du Moulin 2013.webm

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L'atelier du Moulin is the first workshop 
in the manufacturing chain.

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It’s where the different porcelain pastes
are made. There are two varieties

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One is a liquid, called “slurry”,

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and the other is plastic that is used for 
turning, calibrating and moulding.

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That is the pressing stage.

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The machine-operator is closing the pressing filter 

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that removes a certain amount of water from the paste. 

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For the plastic pastes, 30% of the water is retained

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in order to make a workable paste. 

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The pressing filter has to be especially watertight,
so they need to tighten it up well. 

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The extensions allow them to increase the tightness

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using leverage.

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The paste is sent under pressure throughout the machine
filling all the air pockets.

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The water runs out from underneath the machine.

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We can see the sheet of paste that has formed in the centre.

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Each sheet is very expensive
And must be handled with care.

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They start by preparing the pallet

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To receive the sheet of paste.

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In the business, they also use the term “cake” of paste. 

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The process bears many resemblances to cooking!

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Each cake weighs 12 kilograms.

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They centre it carefully on the wire

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so that it can be cut exactly in the middle.

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They make two rows,
they remove the centre, which is too soft 

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and which will be recycled so that they can have 
the most consistent paste possible.

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One by one the cakes are worked, and the separators
are cleaned because they must be very smooth.

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since, if the separator has a fold,
the press will no longer be watertight.

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And the paste will squirt out under pressure.

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Modern trays are made of terpene resin,
which have the advantage of being lighter.

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And do not contaminate the paste. 

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Earlier, they had been made from cast iron,
which was very heavy to handle.

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They had to be repainted regularly,
since they tended to rust,

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which contaminated the paste
with chips of paint or rust.

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However, iron must be eliminated as much as possible
from the paste,

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otherwise it causes staining, 
which ruins the piece.

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While in its liquid state, the paste is therefore
passed through a very fine sieve

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and then passed over magnets to remove 
all traces of iron.

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All impurities that make up more than 60 microns
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Will melt during the cooking process and will become visible.

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If there are fewer than 60 microns, it will have no effect. 

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They start by loading the machine
that kneads the paste, called “la marcheuse”
(the walking machine). 

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Invented in Limoges in 1880,

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the machine replaces the earlier practice of 
putting the paste on the ground

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and walking on it
in order to achieve a uniform consistency.

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The machine is more efficient
and makes the paste more consistent 

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They prepare the “crown”: 

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they stick the cakes together

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to prevent them from being thrown out 
of the machine when it starts up,

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since falling on the ground will contaminate them.

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The vertical height of the rollers is adjusted
to fit the cakes of paste.

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Once the machine starts, they stand by ready to shut it down
if they notice a problem with the paste.

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They put a certain amount of paste in the machine
and, once it starts up, 

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they progressively add more paste 

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until the moment when the paste starts to move forward,
pulled by the rollers. 

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For this machine, that happens at about 250 kg.

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Before they used this machine, they made a heap of paste
and stamped on it with their feet

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starting from the centre and moving out toward the edges.

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Then, they put it back in the middle and started all over again. 

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The machine tries to replicate this process

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With two inverted dark grey rollers:

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one squishes towards the centre, the other towards the edges.

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The two light grey rollers bring the paste back.

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Each dark roller can handle 140 kilograms.

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The machine is stopped and the paste is cut.

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They put what was on top onto the bottom,
and what was on the outside into the centre

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so that all of the paste receives the same treatment from all sides.

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One piece is set aside, to be added later, 

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to prevent the paste from being thrown out of the machine when it restarts.

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In the old days, this was done without stopping the machine,

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in the direction of the rollers.

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For safety reasons, they now stop the machine before performing this step,

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which adds time to the kneading process.

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They take advantage of this extra time to measure the flexibility of the paste

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by dropping a marble in a tube from a known height

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and using a steel ruler to measure the depth it penetrated into the paste.

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This height always empirically corresponds to a certain
level of flexibility achieved,

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suitable for the products they are manufacturing.

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- How much did you measure ?
- 422.

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This bronze paste knife 
Allows them to cut the paste into cakes 

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without sullying it with oxidation. 

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The paste is rounded off, 

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which means that tools or the hands are used 
on the edges to soften the angles,

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which makes it easier to cut out 
and allows the cutter’s hand avoid contact with the paste.

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They make the cakes small enough 
so that they can fit into the de-bubbling machines,

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machines which remove even the smallest bubble of air

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given that the walking machine (“la marcheuse”) 
has already removed all of the large air bubbles.

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To make it easier to separate the cakes,

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The place them in rotation, which prevents the cakes 
from rubbing against each other.

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They meticulously clean the machine with water
after every use.

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since the machine is used to make
four different pastes, each of a different quality. 

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These pastes must never be mixed together. 

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A similarly meticulous cleaning of the tools
ensures that no traces of the paste is left on them.

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They prepare the chest in which they will store the paste
once it comes out of the de-bubbling machine.

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There is water at the bottom of the chest,
to maintain the humidity of the paste.

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They install plasticised boards in the container.

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They change the nozzle.

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They use two different nozzles: 
the larger one, which they have just removed, 

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and the smaller one they will be installing.

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To cut the cakes, they use nylon wire

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again, to avoid contaminating the paste.

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They carefully note which type of paste
remains in the nozzle,

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because they will reuse it.

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They install the new nozzle,

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so that it is able to withstand the very high pressure.

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They set up the table and prepare their tools
so they will be ready once the machine starts.

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They check the oil in the machine
to make sure the gears are well-greased.

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Inside the machine is an auger.

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They prepare some plastic, which will cover
the outsides of the rolls of paste.

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They will place a second tarp crosswise

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to prevent the rolls from sticking together.

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They put the pieces of paste
into the de-bubbling machine’s funnel.

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When the machine starts, they remove
about two and a half rolls’ worth of paste,

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to ensure that they paste they will put in the chest

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is really the same paste that came out of the walking machine.

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You can see that, when they start,
The paste is not very pleasing.

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It will go through the machine a second time,

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where it will be kneaded again.

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There is a slight oxidization from the nozzle
but it is not a contamination.

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The table must be very wet

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so that the tube of paste slides without sticking.

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Next to the table, there is a chute which

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allows the tube of paste to be manipulated without being touched

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Because, when it is soft, 
the pressure of a hand would deform it.

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A tube of paste from the small-nozzle weighs about 17 kg, plus
another 3 kg for the chute, which makes 20 kg.

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With the larger nozzle, that tube of paste would be 27 kg, plus 
another 3 kg for the chute, which makes 30 kg in all.

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When loading the machine, they avoid putting their hands
inside, for safety reasons.

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Instead, they push with the lid.

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Before, the top part was fully open, and it was 
tempting to put your hands inside. 

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But the screw inside the machine is sharp, 
and sometimes they cut themselves when they reassemble it.

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The paste behaves similar to a polish, 
making the cutting edges sharper over time.

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They cannot let the paste dry out too much,

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before it can be worked in the workshop.

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How long it can keep depends on
many different factors, including the weather.

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Ideally, the paste will be used within
a few weeks of its creation.

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One chest will make, for example,
three orders of mugs. 

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that person will only use one third of the contents of a chest.

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Other uses must be found for the remaining contents.

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on the other hand, one chest is not enough

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to fulfill an order for larger pieced, 
such as vases.

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They would need to use part of another chest.

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They measure the flexibility a second time,

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because the de-bubbling machine causes a slight loss of flexibility, 

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due to the high compression, which caused it
to lose a bit of water.

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There is a small disparity between what they measured on the walking machine

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and what they measured on the de-bubbling machine, 

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and this effect is slightly magnified when the small nozzle is used. 

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They must, therefore, anticipate for this reduction.

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Next, they roll the tubes of paste in plastic,

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so that they keep, and they put them in the bottom of the chest. 

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On the chest, they mark the date the paste was made, 

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the type of paste, and the measurement of flexibility of the paste,

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so that the paste leaving the workshop can be monitored.