This information is reprinted from the For Beginners column of Hand Papermaking Newsletter #44 (October, 1998).

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Hollander Beaters

Paper is made in the beater. So goes an old adage, and it’s true that a Western-style papermill lacking this essential piece of equipment is handicapped. Hollanders are difficult or expensive to come by, so less costly yet less efficient methods of reducing raw material to workable pulp are often substituted. There’s nothing quite like a Hollander, though, to create quality pulp for quality paper.

Necessity inspires invention, and 17th-century Dutch papermakers looked for alternatives to the water-powered stamp mills used in Germany. Though the name is lost, and the date is in question (between 1660 and 1682), we know that an inventor in Holland eventually came up with a method for beating pulp that required no river power, did away with the additional time-consuming step of fermentation, and produced a higher quality product. The machine this inventor produced is today named simply after its country of origin.

With rare exceptions, Hollanders are oblong tubs with a central partition called the midfeather, around which water and pulp circulate--like a race track. Spanning one straightaway is a sort of paddlewheel called the beater roll, the steel blades of which revolve above the bedplate, churning pulp up over the backfall where it slides down creating momentum to round the curve and continue the loop.

The tub may be made of stainless steel, iron, bronze, aluminum, fiberglass, sealed wood, even concrete. A common size holds 1.5 pounds of dry fiber in six gallons of water.

The real action happens between the steel bedplate and the blades of the roll. One or the other is adjustable, depending on the model, so space between the two is variable. Allow generous space between roll and bedplate, and a raw material like cotton rag will circulate mostly unchanged. Decrease this space, and the rags get torn and shorn as they are forced between the hard steel surfaces. Stainless steel blades develop rounded edges over time, emphasizing tearing; as other steel alloys wear down they develop sharp edges, emphasizing cutting.

Tearing and cutting begins to undo the process of spinning and weaving that originally created the fabric. Ultimately, through judicious timing and adjustment, the beater operator must separate the individual fibers without cutting them too short or leaving them too long. Short fibers reduce paper strength and long fibers tend to flocculate (form little tufts). Periodically returning to a wide gap between roll and bedplate will help clear beaten pulp of knots.

Plant fibers are long, narrow tubes of cellulose--the main ingredient of plant cell walls. Beater activity separates individual fibers and suspends them in water where they can attract water molecules (become hydrated). To increase the surface area even further, a Hollander beater encourages fiber fibrilation. Fibrils are hairlike abrasions on the surface of the fiber which can attract more water molecules. Fibrilation also creates a more flexible fiber for better interweaving, and helps flatten the fiber to increase density.

Generally, the longer the fiber is beaten, the more water attaches to cellulose, and the slower the pulp drains when a sheet is pulled. The resulting paper is crisp and strong, with high shrinkage. Paper made from pulp beaten for a shorter time is softer and more flexible. This pulp drains freely when a sheet is made, and there is little shrinkage.

Given their expense, most papermakers do not own a Hollander. Some seek access to one at a nearby school or art center. On occasion, a commercial mill research department has donated or sold cheaply a used Valley beater to a very persistent, or well-connected, or extremely lucky papermaker. New Hollanders can be purchased from suppliers such as Lee McDonald, Peter Gentenaar, or David Reina. Rare individuals who know their way around a machine shop can study the workings of a beater and attempt to build their own. (Lee Cooper recently did this. He describes the process in an article in the upcoming issue of Hand Papermaking magazine.) If your future plans include a Hollander-equipped studio, prepare for your new, noisy friend by designing a separate, sound-proof room into the floorplan if possible.

Copyright 1998 Hand Papermaking, Inc.