Hemp: Decorticator etcetra

  Hemp has great potential as an industrial raw material.

france-hemp block

Hemp is one of the faster growing biomasses known,[4] producing up to 25 tonnes of dry matter per hectare per year.[5] A typical average yield in large scale modern agriculture is about 2.5–3.5 t/ac (air dry stem yields of dry, retted stalks per acre at 12% moisture). Approximately one tonne of bast fiber and 2–3 tonnes of core material can be decorticated from 3–4 tonnes of good quality, dry retted straw.[6][7]

Hempcrete is made from the hurds (inner portion).

Hemp is perhaps best known for its Omega-3 and -6 fatty acids that make it a great addition to a healthy diet, and as a cotton substitute in ecologically-sound clothing and bedding. But it is also a versatile, environmentally-sound building material.

A hemp crop can be grown without the use of herbicides or insecticides and produces up to four tonnes of material per acre per year. Hemp is categorized as a bast fiber crop. It has a stem consisting of an outer skin containing long, strong fibers and a hollow wood-like core or pith. Processing the stems results in two materials: hurds and fibers, both of which have properties that make them extremely useful in building construction.

A variety of wood-like products, such as fiberboard, roofing tiles, wallboard, paneling, insulation and bricks, can be made from the compressed hurds. The fibers can also be used like straw in bale wall construction or with mud in a sort of modified cob style of building.

Foundations can be made out of hemp hurds (shiv). A hemp plywood frame is filled with a hemp hurds combined with lime, sand, plaster, some cement and enough water to dampen, and then let to set for a day and to harden for a week. A sixth century hemp-reinforced bridge in France is testimony to the stone-like strength and durability of this material, which has come to be known as “hempcrete”.

Hemp building boosters claim that hempcrete foundation walls are up to seven times stronger than other walls.

Low-impact Living has a good summary. http://www.lowimpact.org/factsheet_hemp_building.htm

it’s very versatile – it can be  used as a replacement for bricks and mortar, plaster or plasterboard; it can be  used as a breathable solid floor; as solid walls that can be internally clad or  plastered; a solid roof / loft insulation; or as a plaster. English Heritage  recommend it for old timber frame infills. It has mainly been used in  historical building restoration, but it is increasingly being used in new builds

Germany is doing a good job of showing that modern industrialproduction is practical.

Hempflax is a major player, with about 6,000 acres in production. It has designed and patented its own machines.

See:  http://hempflax.com/en/dealer-locator

Manitoba has a new plant, capable of processing 5,000 acres.


What happened in North America. DRUGS!!!

  In 1917, the world was battling World War I. In this country, industrialists, just beset with the minimum wage and graduated income tax, were sent into a tailspin. Progressive ideals were lost as the United States took its place on the world stage in the struggle for commercial supremacy.

    It is against this backdrop that the first 20th Century hemp drama was played.

    The story begins soon after the release of Bulletin 404 (see Bulletin 404). Near San Diego, California, a 50-year-old German immigrant named George Schlichten had been working on a simple yet brilliant invention. Schlichten had spent 18 years and $400,000 on the decorticator, a machine that could strip the fiber from nearly any plant, leaving the pulp behind. To build it, he had developed an encyclopedic knowledge of fibers and paper making. His desire was to stop the felling of forests for paper, which he believed to be a crime. His native Germany was well advanced in forestry and Schlichten knew that destroying forests meant destroying needed watersheds.

    Henry Timken, a wealth industrialist and inventor of the roller bearing, got wind of Schlichten’s invention and went to meet the inventor in February of 1917. Timken saw the decorticator as a revolutionary discovery that would improve conditions for mankind. Timken offered Schlichten to grow 100 acres of hemp on his ranch in the fertile farmlands of Imperial Valley, California, just east of San Diego, so that Schlichten could test his invention.

    Shortly thereafter, Timken met with the newspaper giant E.W. Scripps, and his long-time associate Milton McRae, at Miramar, Scripps’ home in San Diego. Scripps, then 63, had accumulated the largest chain of newspapers in the country. Timken hoped to interest Scripps in making newsprint from hemp hurds.

    Turn-of-the-century newspaper barons needed huge amounts of paper to deliver their swelling circulations. Nearly 30 percent of the four million tons of paper manufactured in 1909 was newsprint; by 1914 the circulation of daily newspapers had increased by 17% over 1909 figures to more than 28 million copies.1

    1. World Almanac, 1914, p. 235; 1917

    By 1917, the price of newsprint was rapidly rising, and McRae, who had been investigating owning a paper mill since 1904,2 was concerned.

    2. Forty Years in Newspaperdom, Milton McRae, 1924, Bretano’s NY

    In May, after further meetings with Timken, Scripps asked McRae to investigate the possibility of using the decorticator in the manufacture of newsprint.

    McRae quickly became excited about the plan. He called the decorticator “a great invention…[which] will not only render great service to this country, but it will be very profitable financially…[it] may revolutionize existing conditions.” On August 3rd, as harvest time neared, a meeting was arranged between Schlichten, McRae, and newspaper manager Ed Chase.

    Without Schlichten’s knowledge, McRae had his secretary record the three-hour meeting stenographically. The resulting document, the only record of Schlichten’s voluminous knowledge found to date, is reprinted fully in Appendix I of the paper version of this book.

    Schlichten had thoroughly studied many kinds of plants for paper, among them corn, cotton, yucca, and Espana baccata. Hemp seemed to be his favorite:

    “The hemp hurd is a practical success and will make paper of a higher quality than ordinary news stock,” he said.

    His hemp paper was even better than that produced for USDA Bulletin 404, he claimed, because the decorticator eliminated the retting process, leaving behind short fibers and a natural glue that held the paper together.

    At 1917 levels of hemp production Schlichten anticipated making 50,000 tons of paper yearly at a retail price of $25 a ton. This was less than 50% of the price of newsprint at the time! And every acre of hemp turned to paper, Schlichten added, would preserve five acres of forest.

    McRae was very impressed by Schlichten. The man who dined with presidents and captains of industry wrote to Timken, “I was to say without equivocation that Mr. Schlichten impressed me as being a man of great intellectuality and ability; and so far as I can see, he has created and constructed a wonderful machine.” He assigned Chase to spend as much time as he could with Schlichten and prepare a report.

    By August, after only three months of growth, Timken’s hemp crop had grown to its full height—14 feet!—and he was highly optimistic about its prospects. He hoped to travel to California to watch the crop being decorticated, seeing himself as a benefactor to mankind who would enable people to work shorter hours and have more time for “spiritual development.”

    Scripps, on the other hand, was not in an optimistic frame of mind. He had lost faith in a government that he believed was leading the country to financial ruin over the war, and that would take 40% of his profits in income tax. In an August 14 letter to his sister, Ellen, he said:

    “When Mr. McRae was talking to me about the increase in the price of white paper that was pending, I told him I was just fool enough not to be worried about a thing of that kind.” The price of paper was expected to rise 50%, costing Scripps his entire year’s profit of $1,125,00! Rather than develop a new technology, he took the easy way out: The Penny Press Lord simply planned to raise the price of his papers from one cent to two cents.

    On August 28, Ed Chase sent his full report to Scripps and McRae. The younger man also was taken with the process: “I have seen a wonderful, yet simple, invention. I believe it will revolutionize many of the processes of feeding, clothing, and supplying other wants of mankind.”

    Chase witnessed the decorticator produce seven tons of hemp hurds in two days. At full production, Schlichten anticipated each machine would produce five tons per day. Chase figured hemp could easily supply Scripps’ west coast papers, with leftover pulp for side businesses. He estimated the newsprint would cost between $25 an $35 a ton, and proposed asking an east-coast paper mill to experiment for them.

An early hemp processing machine, c. 1930. Its many fluted rollers crushed the stalks separating the hemp fiber from the woody portion of the plants.

hemp machine

    McRae, however, seems to have gotten the message that his boss was no longer very interested in making paper from hemp. His response to Chase’s report is cautions: “Much will be determined as to the practicability by the cost of transportation, manufacture, etc., etc., which we cannot ascertain without due investigation.” Perhaps when his ideals met with the hard work of developing them, the semi-retired McRae backed off.

    By September, Timken’s crop was producing one ton of fibre and four tons of hurds per acre, and he was trying to interest Scripps in opening a paper mill in San Diego. McRae and Chase traveled to Cleveland and spent two hours convincing Timken that, while hemp hurds were usable for other types of paper, they could not be made into newsprint cheaply enough. Perhaps the eastern mill at which they experimented wasn’t encouraging-after all, they were set up to make wood pulp paper.

    By this time Timken, too, was hurt by the wartime economy. He expected to pay 54% income tax and was trying to borrow $2 million at 10% interest to retool for war machines. The man who a few weeks earlier could not wait to get to California no longer expected to go West at all that winter. He told McRae, “I think I will be too damn busy in this section of the country looking after business.”

    The decorticator resurfaced in the thirties, when it was touted as the machine that would make hemp a “Billion Dollar Crop” in articles in Mechanical Engineering and Popular Mechanics.* (Until the ninth edition of The Emperor, the decorticator was believed to be a new discovery at that time.) Once again, the burgeoning hemp industry was halted, this time by the Marijuana Tax Act of 1937.


1995 summary article from Ontario.


includes lots of cost analysis.  Bahmer Company are going into operation in June, each having an hourly
processing capacity of two tonnes of flax and/or hemp fibre. Two of the lines
are intended to process flax into a fine short fibre for the textile industry,
but will likely also process hemp. The third unit is combined with a detergent
processing step which produces a very fine, cotton-like flax fibre

1998 article from Oregon.


Net Projected Return



Hempflax: German Company

In production. http://hempflax.com/en/about-hempflax

Optimum use of this renewable resource
Today HempFlax harvests and processes 2400 hectares (5930 acres) of fibre hemp per annum. The crop is converted into a flexible combination of products. The processing, manufacturing, application and marketing chain is aimed at optimizing the application of this sustainable resource. Hemp wood is used as stable litter and in small pets’ cages. Hemp fibre serves as a raw material in the production of special paper. The automobile industry uses the fibre in its pressed form for manufacturing parts such as door panels and dash boards. Together, hemp fibre and hemp wood are turned into paper and construction material. All these products can be re-used several times and/or composted after use. Dust, a residual product, is already being used as compost and has great prospects as a plastic granules filler. In future the complete hemp plant may be utilized as biomass.

Another very through summary: with lots of historical references.


Good harvesting images from Romania.


Old mill but making silky hemp. Very complex.



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