“Bite-Size Bits of Local, National, and Global History”
“Bite-Size Bits of Local, National, and Global History”
Thurmont in Frederick County, Maryland — The American Northeast (Mid-Atlantic)

“Isabella” and Casting Shed

Catoctin Iron Furnace

"Isabella" and Casting Shed Marker image. Click for full size.
By Don Morfe, October 22, 2011
1. "Isabella" and Casting Shed Marker
A Village and Its Resources:
The quiet village of Catoctin Furnace was a bustling industrial community that began in the 1700s around the Iron-making complex James Johnson built the first furnace with financial assistance from Thomas Johnson, a governor of Maryland during the Revolutionary War. Attorney Baker Johnson later owned the furnace. This location was chosen because of the availability of natural resources in the area and the relatively poor transportation of that time. No canals, trains or trucks existed to move the raw materials which weighed at least 10 times more and took up 100 times more space than the finished product. The “Mountain Tract” (much of which is now Cunningham Falls State Park and Catoctin Mountain Park) provided hardwoods for making charcoal, iron ore, limestone, and water power.

The Furnaces:
“Isabella”, the furnace stack before you, was built in 1858 and was the second of three stacks. The first furnace, built in 1776, was probably located behind “Isabella” and used water power from Little Hunting Creek to operate its bellows. “Isabella” and the third stack “Deborah” (dismantled) used steam driven pistons to create the blast of air which fanned the fire within the furnace. All three furnaces had different capacities

Catoctin Iron Furnace image. Click for full size.
By Don Morfe, October 22, 2011
2. Catoctin Iron Furnace
and “Isabella” produced up to 3300 tons of pig iron annually.

The Iron Making Process:
The operation of the furnace involved several steps. First, the furnace stack was filled from the top with a thick layer of charcoal, a layer of iron ore, and finally limestone to act as a flux mixing with the impurities in the iron ore creating slag.

The furnace was then heated to 3000 degrees F to melt the iron ore. The furnace operated 24 hours a day when making iron. Approximately every 12 hours, foundry men tapped the furnace. Molten iron flowed into channels on the floor of the casting shed. The molten iron was allowed to harden into iron pigs or cast into wooden molds. The name “pig” iron came from the shape which reminded foundry men of a sow suckling a litter of pigs. Iron was made into many items such as cannon shells, stoves, tools nails, and wheels.

The 200 foot rock retaining wall once supported many wooden building and sheds which housed the raw materials for iron-making. The wall and furnace stack were constructed of local fieldstone hand cut by stone masons. The casting shed with the wood-shingle roof was reconstructed in 1975. All other stone remains are original.

Imagine yourself standing here when “Isabella” as alive. Noise and clatter surrounds you. The air smells of smoke and rotten eggs (sulfur). A fine red

Catoctin Iron Furnace image. Click for full size.
By Don Morfe, October 22, 2011
3. Catoctin Iron Furnace
Isabella Blast Furnace
dust from iron oxide (rust) and clay sprinkle on and around you. The air is almost always hot.
Location. 39° 34.428′ N, 77° 25.878′ W. Marker is in Thurmont, Maryland, in Frederick County. Marker is on Blacks Mill Road. Click for map. Marker is in this post office area: Thurmont MD 21788, United States of America.
Other nearby markers. At least 8 other markers are within 4 miles of this marker, measured as the crow flies. Catoctin Iron Furnace (here, next to this marker); Catoctin Furnace (within shouting distance of this marker); a different marker also named Catoctin Iron Furnace (within shouting distance of this marker); Lewistown (approx. 2.5 miles away); Cunningham Falls (approx. 2.6 miles away); Lewistown Trout Hatchery and Bass Ponds (approx. 2.6 miles away); The Brotherhood of the Jungle Cock (approx. 3.4 miles away); Thurmont Memorial Park (approx. 3.6 miles away). Click for a list of all markers in Thurmont.
Categories. Industry & Commerce
Catoctin Iron Furnace image. Click for full size.
By Don Morfe, October 22, 2011
4. Catoctin Iron Furnace
Retaining Wall
Catoctin Iron Furnace image. Click for full size.
By Don Morfe, October 22, 2011
5. Catoctin Iron Furnace
Casting Shed
Credits. This page originally submitted on , by Don Morfe of Baltimore, Md 21234. This page has been viewed 405 times since then and 14 times this year. Photos:   1, 2, 3, 4, 5. submitted on , by Don Morfe of Baltimore, Md 21234. • Bill Pfingsten was the editor who published this page. This page was last revised on June 16, 2016.
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