The top stack of the furnace is usually made from a rolled steel cylinder which has to be lined with refractory in order to stop the iron from melting through the steel. In industrial scale blast furnaces the lining is knocked out and replaced after each time the furnace is used. The lining in contemporary cast iron art furnaces are relined when the lining degrades, depending on how often the furnace is run. This lining of the furnace seems symbolic of the uterine lining, detaching, shedding and regrowing as a cyclical action.
The furnace is filled with iron that can be seen melting through the tuyeres, the transition is marked by the dripping of glowing white liquid filtering through the layers of coke (fuel). Alongside the tuyeres being used to see what is going on inside the cupola, they also feed the furnace with air from the fan belt. The forced air is what creates the blast zone inside the furnace, allowing it to get up to such a high temperature in order to melt the iron. This could be reflective of an umbilicus, giving the fire the life it needs to gestate the fetus inside of it.
The tap hole retains the same representation of vaginal opening as the traditional, hand built smelting furnaces. Tapping the furnace to release the iron correlates with dilation. A tapping bar is pushed into the sealed tap hole then rotated so that the tap hole is widened. When it is pulled out it releases the flow of molten iron and the birth occurs. People are gathered round focused on the furnace, in her moment of glory for this release of volatile offspring.
The slagger is positioned higher than the taphole and in most cases on the opposing side. When running cupolas it is used to determine when the correct amount of iron sits in the well to tap. Slag is all of the impurities of iron mixed with marble as a flux. It is lighter than iron and therefore floats on top of it. The iron will fill up the well and allow the flux to rise up and out of the slagger. Once iron starts to flow out of the slagger it is clear that the furnace is ready to be tapped. This purpose of the slag here is to pre warn the flow of iron as well as separate the impurities from it. ‘The running of molten slag is equated with the rupture of the waters and the beginning of the labour pains.’ (Herbert, 1993).
Unlike traditional smelting furnaces or coupolette furnaces, the slag does not come out of the tap hole and therefore is unlikely to be seen as any sort of afterbirth. Instead it could be construed as spotting, discharging of the mucus plug, or the water breaking: that warning to labour. Alternatively the slag could be seen as fecal matter due to its waste properties and the placement of the slagger on the opposite side to the tap hole. Others regard it as the flow of menstruation ‘both are waste products of the creative process.’ (Herbert, 1993).
It is difficult to say whether one tap could be considered the action of birth or if the taps become cumulative impressions of contractions. The longer the furnace is run, the closer together the taps occur as the heat of the furnace intensifies. Perhaps the whole process is considered a birth, the procedure either culminating in the last tap or all of the taps being seen as one. Either way the crux is that release of molten metal. Once the final tap is complete the bottom of the furnace has to be dropped to avoid the iron freezing inside of it, making the furnace unable to be used again. The bottom of the furnace dropping out is synonymous with the afterbirth, the clearing and the completion.
To aid the furnace in these motions is the ultimate simulation of the female. The pain and physical exertion (labour), the heat, concentration and lethargy, the overwhelming feeling of achievement and production. As if to experience birth itself.
