Newlin Grist Mill Research Projects

Experimental Archaeology

As a branch of archaeological study, experimental archaeology replicates or attempts to replicate past processes to understand how things were made, explore how archaeological deposits were created, and study lost production techniques. This includes making tools and objects, recreating manufacturing techniques, and reconstructing structures, complexes, and entire villages. At Newlin Grist Mill, experimental archaeology includes making hand-made brick, bloomery iron, and potash. The challenges associated with experimental archaeology include finding appropriate materials, recreating processes long removed from living memory, and determining how to scale down processes without affecting the outcome. Many of these processes are included as demonstrations during the annual Fall Harvest Festival.


Bloom Iron

Bloomeries were once a common method of manufacturing wrought iron. A small bloomery furnace is charged with alternating layers of charcoal and iron ore. After several hours of firing, the iron ore congeals into a mass called a bloom and the slag is tapped and runs out the bottom. The bloom is removed and then hammered and repeatedly folded until it forms wrought iron.

Newlin Grist Mill has had mixed success with its bloomery operation since beginning to experiment with the process in 2010. We continue to refine our technique. To see images of the iron-making process, watch the slide show.

Roasting iron ore in preparation for the burn.
Roasted iron ore.
Preheating the bloomery.
Layers of iron ore and charcoal are added to the bloomery as it burns down.
Bog iron ore collected along the Chesapeake.
Tapping the slag.
Tapping the slag
Removing the bloom
Cutting the bloom into smaller, workable-sized pieces.
Hammering the bloom iron.
Folding the bloom iron repeatedly until in forms in wrought iron.
Mill bill made from the bloom iron.

Brick Making

In 2012 and 2013, NGM partnered with New Castle Historical Society (NCHS) to reproduce bricks for a hearth restoration. While restoring a chimney in the Historic Amstel House, a fragment of a special hearth brick was discovered. NCHS decided to manufacture replacement bricks for the hearth restoration and approached NGM. The planning team examined sources on brick making tools and techniques and spoke with individuals involved in brick making projects.

During the first two seasons, the team of staff and volunteers learned many lessons about processing and handling the clay, working with moisture content, and firing the bricks. To see images of the brick making process, watch the slide show.

Analyzing the sand and sediment content of the clay
Moving tempered (or aged) clay into treading pits
Treading the clay to prepare for molding
Clay after 2 hours of treading, untread, and after 4 hours of treading (bottom to top)
Working the clay on the moulding table
Throwing the clay into the molds
Removing the excess clay
Marks left by the wooden striker and the wire tool
Stamped brick to mark the it's date of manufacture for inclusion in the restoration
Drying in the sand beds for 3 days flat and for 3 days upright (before going into the barn to dry and store until firing)
Stacking the bricks in the brick clamp or kiln
Firing at low heat for approximately 24 hours to remove remaining moisture
Firing the clamp for 5 days around the clock
Steel doors during firing
Bricks during firing

Potash Manufacturing

Potash was an important ingredient in many manufacturing processes including glass, soap, and pearlash. During the 18th century, England had a shortage of the much used material and looked to its colonies in North America. Potash is created from hardwood ash and colonists were clearing large tracts of land each year. Several pamphlets were printed instructing colonists how to make potash. Using these colonial instructions, Newlin Grist Mill with the assistance of historian Patrick Harshbarger has tried to recreate the process.

Hardwood trees were burned in the manner instructed to create the most ash and then the ash was boiled to reduce into potash. To see images of the potash manufacturing process, watch the slide show.

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