Kosfeld Fenna Thesis - Flipbook - Page 99
Extrusion Moulding
Another technique of forming 昀椀ne ground
biochar is through extrusion moulding, where
instead of intense pressure, the material is
gently guided through a tube. Material consistency when extruded must be moist and slimy,
enabling smooth extrusion and post-drying
surface.
Because bicohar tubes are moist from all sides,
they can be layered and stick together immediately; in fact, they bind as if they are one paste,
which results in less accurate layering but simultaneously one larger surface.
Due to the water content in the recipe, fresh
material is heavy and sinks under its weight.
Therefore, building up rather than laying from
the top down makes the structure more stable.
Grain Size for Extrusion
Moulding should be very 昀椀ne
for more structure.
Large pieces, like those to the right, can collapse easily under the weight of material due to
water and moisture content. In the case of larger structures, material needs to sit for a while (1
day ) to enable thickening and strengthening of
material.
( Wanbo machinery )
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