Preparing plant fibre for papermaking

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After weeks of living with various broths retting, simmering and boiling in our studio backyard, now might be a good time to reflect on general fibre processing for hand papermaking.

The papermaking process commences with fibre harvesting and it is true that different types of fibres require different methods of preparation. Yet, there are some rule of thumb applications to consider when experimenting with ‘unfamiliar’ fibres.

Plants that have a history of being used for weaving are often suitable for papermaking.

  • When harvesting, pay attention to the needs of the plants. For example, bulbs need leaves to regenerate, so don’t harvest leaves from bulbous plants before the leaves have fallen to the ground.
  • For stronger paper, you need stronger fibres and therefore it is better to harvest plants later in the season.  If possible, allow plants to seed first.
  • Always obtain proper permission before removing any plants.

Back at the studio, if the fibre you have collected is not uniformly dry, hang it to dry in a well-ventilated place. If ventilation is poor, you might end up with mouldy fibre and no paper.

NOTE: “Green” fibre might have a shorter boiling period, but it might be foaming during the boiling and you may also end up with weaker paper. Ask yourself, ‘Is it worth the short cut?’

When your fibre is dry, cut it into 10cm lengths. If your harvested grassy fibres (e.g. bamboo or straw) have nodes, remove and discard the nodes. Weigh the fibre and note the weight down.

TIP: If you know you will have several batches to boil, it might be worth your while to weigh and store the dried fibre in 1kg bundles.

Soak the cut fibre for a day or more in water. Generally, fragile leaves can be soaked for a shorter period. I soak leaves from bulbous plants for one day and tough leaves, e.g. flax, for up to a month. Cover the container in which your fibre is retting or replace water daily to discourage insect infestation. Look out for mould too.

Finally, it is B-day. We use a camping cooker/hot plate connected to a gas cylinder for our ‘garden broths’. Always use a stainless steel pot, or the caustic solution will destroy your pot before your first batch of fibre is boiled. Wear protective clothing, thick rubber gloves, safety glasses and slip free shoes.

Place the fibre in the pot. Pour enough cold water in to cover the plant material. Now add 2 heaped teaspoons of caustic soda for each 1kg of plant fibre. Turn your cooker on. Once it boils, turn it down to simmer to prevent dangerous corrosive spills.

Depending on the fibre, the boiling process should take between one and three hours. However, there are exceptions, such as palm fibre, which can be particularly obstinate to break down. You will realise this when after several hours of boiling your fibre is no softer to the touch.

To successfully boil palm and other tough fibres, keep the pH above 10 otherwise you might as well be watching paint dry. Use litmus paper to test the pH. If the pH is below 10, add another teaspoon of caustic and test again.  Keep on adding caustic until you have reached the desired pH. Every so often test the pH of the solution, as the solution will gradually become more acidic throughout the cooking process. Palm fibre can easily take 8 hours (or more!) to boil.

Your fibre is ready for papermaking when it is slimy to the touch (with a gloved hand!) and the fibres separate easily when you rub it (with a gloved hand!).

Once the fibre is ready, remove from the boil and rinse, rinse, rinse until the water runs clear. Happy papermaking.

Testing Plant Fibre
Testing Plant Fibre

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