Blast furnace 1738
The scale model of the Fiskars blast furnace is built to a scale of 1:20 and most of the materials used are the same as those used to build the original eighteenth-century blast furnace: stones were collected from the ironworks' old quarry; the wood is local; the iron ore in the model is of the same kind as was used originally.
The model was built in 2005 by the artist and miniature-maker Taina Pailos, who lives in Fiskars Village. Expert advice on the building of the scale model was received from historian Erkki Härö of the National Board of Antiquities, and engineer Gunnar Lundqvist who provided technical solutions. The lights, smoke and sound effects for the scale model were designed by lighting expert Juha Westman.
It's the year 1738 at Fiskars
A new charcoal blast furnace has just been built at Fiskars and pig iron is being tapped into a sand mould nearby. The new blast furnace is a so-called German type of timber-clad construction and about 8 meters high.
In 1738, the blow of the blast furnace (the period it was 'on') lasted from January to the end of May. For an entire 128 days the furnace worked nonstop, night and day. At night, especially, the furnace mouth flame and the cloud of smoke around it made a dramatic sight.
At this time, the Fiskars ironworks belonged to John Montgomerie, a Scottish merchant who lived in Stockholm. One of the wealthiest men in Sweden-Finland, he owned the large ironworks of Skebo and Forsmark in Sweden, and in Finland his chain of ironworks included not only Fiskars but also Antskog, Koski, and Kulla.
In 1734, as the only ironworks in Finland, Fiskars and Antskog had begun smelting and forging using the Walloon method of iron-making.
The Walloons were skillful smiths, blast furnace masters, and charcoal burners, who came to work at the Swedish ironworks from regions known today as Belgium, Luxemburg and northern France. They spoke French and were mostly Calvinists. In foreign parts, they and their descendants maintained their own culture and identity, much of which has survived even to this day.
Iron made using the Walloon method was of an especially high quality and much sought after. Montgomerie owned a share of the important Herräng iron mine in Roslagen, Sweden, from which the ore was particularly well suited to Walloon forging.
The iron ore from Herräng was first transported by sailboats to the port of Pohjankuru (Skuru) and from there by barges and horses up the Fiskars River to the blast furnace. Close to the furnace, the ore was first heated in big ore roasting pits to remove the worst of the dross, or scum. Next, the ore was crushed into hazelnut-sized chunks in the iron ore crusher that was powered by a water-wheel and stood by the blast furnace. An ore hoist was then used to bring the crushed ore up to the work area known as the furnace top house.
The charcoal needed to melt the ore was conveyed to the top house over a long charcoal bridge from a large charcoal store kept near the blast furnace. The blast furnace process also required some limestone.
In the top house the stack was charged at regular intervals with charcoal, ore, and limestone in a ratio carefully specified by the blast furnace master. The heat required to melt the ore was achieved by using the pair of pointed bellows positioned at the foot of the blast furnace. It too was powered by a water-wheel. The blast was conveyed to the lower part of the stack through the tuyère arch.
Two or three times a day, molten iron was tapped off through the tapping arch in the casting house at the foot of the blast furnace. But always prior to that process, the slag was tapped off. When it set, the slag was a clear blue glassy substance which then accumulated in the slag heaps that gave a distinctive look to the entire ironworks village.
The Walloon method of iron-making required that the so-called pig iron produced at Fiskars was cast into 'sows' of 4–5 meters which weighed some 800–1000 kilos. Transporting just one of these sows to Antskog for further processing at the bar iron forge was the work of 8–10 men.
The iron from Fiskars and Antskog, after being processed into forgeable bar iron, was sold through Stockholm to various parts of Europe, particularly to England. In 1738 the ironworks produced approximately 150 tons of iron.
In the 1750s, the old timber-clad blast furnace at Fiskars was replaced by a bigger furnace built entirely of stone. In 1802, the smelting of iron ore at Fiskars came to an end, and the last blast furnace was demolished to make room for other processes. All the Fiskars blast furnaces from the 1650s onwards have stood approximately where the small-scale blast furnace now stands.
Text: Erkki Härö, 2005
