Sheet Forming

Part of Paper Making

Sheet forming is the moment when a suspension of fibers in water becomes a sheet of paper. The technique you use — how you dip the mold, how thick you make the pulp slurry, and how you transfer the wet sheet — determines the paper’s thickness, uniformity, and strength.

Why Sheet Forming Matters

A poorly formed sheet is lumpy, uneven in thickness, has thin spots that tear and thick spots that dry slowly and cockle. A well-formed sheet is uniform, smooth, and strong. The forming step takes only seconds per sheet, but those seconds require skill and consistency built through practice. This is the heart of papermaking — everything before it is preparation, and everything after is finishing.

The Mold and Deckle

The mold and deckle are the only specialized tools required for sheet forming. Together, they define the sheet size and determine the paper’s texture.

The Mold

The mold is a flat screen stretched over a rigid frame — the surface on which pulp is deposited.

Construction:

1. Build a rectangular wooden frame from straight-grained hardwood (ash, oak). Size determines your paper size — a 30x40 cm mold makes A3-sized paper.
2. Cross-bars (ribs) run across the shorter dimension every 2-3 cm for support
3. Stretch a screen material tightly across the top:

Screen Material	Paper Texture	Availability
Woven cloth (linen, cotton)	Smooth, no laid lines	Easiest to find
Split bamboo or reed strips	Traditional “laid” lines visible	Requires bamboo
Woven wire mesh	Smooth, professional	Requires metalworking
Woven grass or rush	Rough, textured	Abundant everywhere

4. Tack or lace the screen to the frame, pulling it as taut as possible. The screen must be flat and smooth — any sag produces thick and thin areas.

Cloth Screen for Beginners

Start with a tightly woven cotton or linen cloth stretched over the frame. This produces a smooth-textured paper and is forgiving of technique errors. Graduate to bamboo or wire screens once your forming technique is consistent.

The Deckle

The deckle is a second frame, identical in outer dimensions to the mold, that sits on top of the mold screen. It acts as a fence that contains the pulp and defines the sheet edges.

Construction:

1. Build a frame matching the mold’s outer dimensions exactly
2. It should sit flat on the mold with no gaps
3. Height of 2-4 cm is sufficient
4. No screen — it is just an open frame

The deckle’s edge creates the characteristic feathered border (the “deckle edge”) on handmade paper. For clean edges, the deckle must fit tightly against the mold.

Preparing the Vat

The vat is a large, shallow container filled with diluted pulp — the “stock” from which sheets are pulled.

Vat Construction

Any large, watertight container works:

• A wooden barrel sawn in half
• A clay-lined wooden box
• A stone trough
• Even a large cooking pot for small sheets

Dimensions: The vat must be at least 10 cm wider and longer than the mold on each side, and 15-25 cm deep.

Mixing the Stock

1. Add beaten pulp to the vat
2. Add water until the consistency is correct — this is the single most important variable

Stock Consistency	Appearance	Paper Result
Very thin (1-2% fiber)	Barely cloudy water	Thin, translucent paper — writing paper
Medium (2-4% fiber)	Milky, opaque	Standard weight — general purpose
Thick (4-6% fiber)	Porridge-like	Heavy card stock, covers

3. Stir thoroughly — fibers must be evenly distributed with no clumps
4. Stir before every sheet — fibers settle continuously. Agitate the vat before each dip.

Stir Every Time

Pulp fibers settle toward the bottom of the vat within seconds. If you dip the mold without stirring first, you will pull a thin, inconsistent sheet from the fiber-depleted surface water. Stir the vat vigorously before every single sheet.

The Dipping Technique

Western Method (Single Dip)

The traditional European technique — one dip per sheet:

1. Stir the vat with your hand or a stick
2. Hold the mold with the deckle pressed firmly on top, screen side up
3. Dip — Insert the far edge of the mold into the vat at a 30-45 degree angle
4. Level — In one smooth motion, lower the near edge so the mold is horizontal and submerged just below the surface
5. Lift — Raise the mold horizontally out of the stock. The screen catches fibers as water drains through.
6. Shake — While the water is still draining, give the mold two or three quick side-to-side shakes, then two or three front-to-back shakes. This interlocks the fibers and evens out the sheet.
7. Drain — Hold level until water stops dripping through. The wet sheet now sits on the screen.
8. Remove the deckle — Lift the deckle straight up without touching the wet sheet.

Eastern Method (Nagashi-zuki)

The Japanese technique — multiple dips build up thickness:

1. Dip the mold (no deckle), scooping a thin layer of stock
2. Rock the mold to spread fibers evenly
3. Pour off excess stock from one edge
4. Dip again, adding another thin layer
5. Repeat 2-5 times until the desired thickness is reached

This method produces exceptionally even, strong paper because fibers from each layer cross at different angles, creating a woven-like structure. It requires more skill but produces superior paper.

Forming Tips

Speed and Confidence

The dip should be one fluid motion — enter, level, lift, shake — taking about 3-4 seconds total. Hesitation causes uneven fiber distribution. Practice the motion with plain water before using pulp. Confidence produces consistency.

Thickness control:

• Thinner paper: use more dilute stock, or dip less deeply
• Thicker paper: use more concentrated stock, or dip deeper
• Consistency comes from maintaining the same stock concentration and the same dipping motion for every sheet

Troubleshooting:

Problem	Cause	Fix
Thin spots	Uneven dip or insufficient shake	Level the mold faster; shake more
Thick edges	Holding the mold too long	Drain faster — gravity does the work
Holes	Clumps in pulp or damaged screen	Strain pulp better; repair screen
One thick side	Tilting during lift	Focus on lifting horizontally
Fiber clumps	Insufficient beating or stirring	Beat longer; stir vat before every dip

Couching (Transferring Wet Sheets)

After forming, the wet sheet must be transferred from the mold to a felt or cloth for stacking and pressing. This transfer is called couching (pronounced “cooch-ing”).

Process

1. Prepare a couching surface — A damp wool felt, thick cotton cloth, or smooth blanket laid on a flat board.
2. Invert the mold — Turn the mold upside down, wet sheet facing the couching surface.
3. Apply gentle pressure — Press the mold down onto the felt, rocking from one edge to the other. The wet sheet transfers from the screen to the felt.
4. Lift the mold — Peel the mold away carefully. The sheet should stay on the felt.
5. Cover with another felt — Lay a second felt on top of the deposited sheet.
6. Repeat — Form and couch subsequent sheets, alternating sheets and felts to build a stack (called a “post”).

Couching Speed

Do not hesitate once you begin the couching motion. A slow, uneven press wrinkles the sheet or transfers it incompletely. One smooth, firm roll from edge to edge works best.

Couching Without Felts

If wool felts are unavailable:

• Use cotton or linen cloths between sheets
• Smooth, dampened boards work for thick sheets
• In the Japanese method, sheets are couched directly onto each other without any interleaving — a thin film of water between sheets prevents them from permanently bonding

Pressing

After building a post of alternating sheets and felts, the stack is pressed to remove excess water.

Press Construction

A simple screw press or lever press works:

1. Board press — Place the post between two flat boards. Stack heavy stones on top. The weight squeezes water out through the felts.
2. Screw press — A wooden frame with a screw mechanism that applies controlled, even pressure. This produces flatter, more uniform sheets.
3. Lever press — A long beam pivoting on a fulcrum, with weight at the far end pressing down on the post.

Pressing Procedure

1. Apply light pressure initially and increase gradually over 30-60 minutes
2. The post compresses and water drains from the bottom
3. After pressing, separate the felts and sheets carefully
4. Sheets are now about 60-70% water — firm enough to handle but still wet

Drying

Air Drying

1. Hang sheets on lines (drape over smooth ropes or sticks)
2. Or press sheets onto smooth boards and lean against a wall
3. Dry in shade with good air circulation — direct sun causes uneven drying
4. Drying takes 4-24 hours depending on humidity and sheet thickness

Board Drying (Best Quality)

For the flattest, smoothest paper:

1. Brush wet sheets onto smooth wooden boards (planed hardwood or smooth plaster walls)
2. The sheet sticks to the board surface as it dries
3. The constraint prevents shrinkage and curling
4. Peel the dry sheet off the board when fully dry

Japanese Board Drying

Traditional Japanese papermakers dry sheets on smooth wooden boards set at an angle to catch sunlight. Each sheet is brushed onto the board using a soft brush. The wood absorbs moisture from the back while the sun dries the front, producing perfectly flat, smooth paper.

Common Mistakes

1. Not stirring the vat — Fibers settle in seconds. Failing to stir before each dip produces thin, inconsistent sheets. Make stirring automatic — it is part of the forming rhythm.
2. Hesitant dipping — A slow, uncertain dip produces uneven fiber distribution. Practice the motion until it is fluid and confident.
3. Too-thick stock — Beginners often make the stock too concentrated, producing heavy, thick paper. Start thin and add pulp gradually until you reach the desired weight.
4. Couching too slowly — Hesitation during couching wrinkles the sheet. One firm, smooth roll from edge to edge.
5. Drying in sun or wind — Direct sun and wind cause uneven drying, which cockes and wrinkles the sheet. Dry in shade with moderate airflow.

Summary

Sheet Forming — At a Glance

• Build a mold (screen on frame) and deckle (matching open frame) to define sheet size
• Mix pulp in the vat to 1-4% fiber consistency depending on desired paper weight
• Stir the vat before every single dip — fibers settle in seconds
• Western method: one dip with shake produces standard sheets; Eastern method: multiple thin dips produce superior strength
• Couch (transfer) wet sheets onto felts by inverting and rolling the mold firmly
• Press the stack to remove water, then air-dry in shade or board-dry for flattest results
• Speed and consistency produce good paper — practice the dipping motion until it is automatic