Eisengießerei in Goslar | Die Nordreportage | NDR DokuJan 14, 2022
Subtitle: Norddeutscher Rundfunk 2022 Liquid. Just take it easy. That gives a babble. Or firmly: iron. A millimeter or two. This is where it starts to tip over. Yes. This is where it starts to tip. Exactly. He is still working against the chimney, the right elevator is still missing. I can see it in the flame: It could be so far. A century-old craft. Is it so? Are they inside backwards? 7 a.m. m., iron foundry in Goslar: Production manager Andreas Jacobi is under stress. He is going to cast a 2.5 meter iron ring. We are looking for iron. The most important ingredient is missing: pig iron. oh oh man He is not here yet.
This is hematite iron, pig iron, we need nodular iron. Delivery problems, it takes time, we don't get it that fast. Before Corona it was fast, you paid, then it worked. Now you have to stay on the ball. It is an important request for Andreas Jacobi and his team. The ring is for an industrial plant. The mold for this is almost ready. This will be a treadmill. 1.8 tons of weight. We're still working on it, two pieces. Then there is a cogwheel. It is already being prepared. And a big pinion. It took 25 hours to build the sand mold.
It consists of two parts: The upper one must now be placed on top of the lower one. When we turn, nothing should fall out, everything should be tight. And it has to be tight, so we make a seal around it. Nothing should happen here, because the viscosity of liquid iron is not that far from that of water. Basically, it has to be almost waterproof. He climbs very high here, there is still pressure on him. The mold only weighs five tons. Good. Let's see again. Expect! Oh! You have? Understood. disappointed. That was good. Hold on tight! Hold on tight!
Hold on tight! Now we have to look. The boxes must be exactly on top of each other. Otherwise, the liquid iron will run out of the holes when pouring. Everything is there too. It doesn't touch the ground. You see it? Here. The gap is too big, we have to bridge this. Andreas wants to throw the ring tomorrow at the latest. The client is waiting. You can't plan ahead. I hope the truck will be there in the morning. If not, I'll have to switch back and see what we can do. But the important thing is that the main thing is that we can move forward.
At least the little stove should burn today. With the remaining iron they want to make at least a few smaller pieces. Felix Krause and Ingo Wormus are the founders. Throw a ton of iron and push it into the furnace. Ingo has been doing this for over 30 years. Before he wanted to do many things: bricklayer, this, that and that. I ended up in the foundry, I looked at it: I liked working with fire and ovens, then I learned that. Cast iron is used when components need to be as robust and in one piece as possible. Defy water and weather.
From ship propellers to pumps and streetlights. The finished castings are shaken out of the molds. The sand mold is broken. Each shape must be built separately. It will be a way. For a cast image with animals. Moldmaker Walter Schulze fills the box around the model with sand. This will be the negative form. * Rattle * Small parts are particularly filigree and sometimes go wrong. Cleanliness is everything. You can see dirt everywhere. Then you'll have holes if you don't do it... ...carefully. Now all you have to do is take the model out of the sand. Now... ...looks good. Finally, paint each shape with a protective coating.
It does not work without the "simple". It would burn. It's like frying an schnitzel without fat. Then it also burns. This is where the size is applied. Otherwise, we will have a thick crust. So that the iron can then flow well into the mold, it has to be around 1400 degrees of temperature. Melter Ingo Wormus takes care of that in the next hallway. The oven has been running for two hours. The iron inside is already hotter than the lava. Ingo has to be careful that the stove doesn't burn. That's how I notice it, everything is still cold.
It's happened a few times already. The drum is over 100 years old. A protective layer of clay remains in the kiln. The feed.â Without lining, the kiln wall would melt. The lining needs to be repaired every 500 batches. Holes and dents appear. , changes. Somewhere it's more and less. At a higher point, the iron pushes higher. Then it comes out the back. That's what happens when the furnace is so full. Not bad, say the men. Varel, Lower Saxony, a villa from 1899. Interior: a very special treasure. Let's see where we can find it. A cast iron stove. Andrea and Stefan Fuhrken want to pick it up.
They are passionate stove restorers. It's exciting every time. What kind of Is that oven? How is the condition? Where is it? How can you dismantle it? How do you get it outside? Can you disassemble it? We'll see. Hi, Andrea. Good morning. Hello. The host Frank Walther has his villa restored. An old cast-iron stove should also be re-arranged. der if it can still be saved. Something has happened here. It's progressing. Can we take a tour? Yes. This used to be the village's coal cellar. Oh good. I'll turn on the light. Excellent. There's the oven. Very beautiful. A gem.
Very beautiful. Of course it's great. It was always in the dining room of the villa. Oven builder Stefan immediately recognizes how the oven works. It is a "circulation oven". It only needs a little fuel to warm up well. The hot smoke circulates from left to right, flowing through these elements until it flows into the chimney. This ensures that such a box furnace or circulation furnace reaches a very high level of efficiency. Because the flue gases take so long to flow through the furnace, it gives off a lot of heat. Whether it will reheat a room depends on the damage.
If the parts have to be recast, that would be beyond the budget. A crack back here on the plate. Do you have a crack in the plate? Yes. Do you have to come to the other side? Cast iron is harder than steel, but it also breaks faster. Too big a fire has been made in the oven. The iron is cracked in many places. Steel, on the other hand, rusts, like an ashtray. Here you can see the difference between the material cast iron, which develops a patina on the surface, that is, it does not rust. It only starts to rust on the surface and lasts for ages.
Steel, due to the heat generated by ash and the like, moisture, of course, corrodes. Andrea estimates that the oven is over 160 years old. Her passion is the story behind the stove. She is looking for clues as to where the oven was built. That looks like an S. Could it be an S? C and S. Or a number? Or a me? Or a 51. And a C. It's incredibly exciting. I have a lot of pattern books and am starting to dig through them to see if I can find anything on the maker. For restoration, the stove has to go to the workshop.
It weighs around 320 kilograms. Luckily, it's easier to disassemble than a piece of furniture. Are you holding up? Otherwise orâ¦ you can do it to me too, sometimes they are unstable. It consists of 40 individual castings. Oh! That's a different kind of damage. But it can still be fixed. But the firebox will be here soon. You know that this is often where the most damage is hidden. Should I take that off? You can lose weight. And Frank and I fix... the parts. They are relatively good. A crack in the rear wall runs through the entire combustion chamber. They show spot welds - here someone has already tried to repair the furnace.
There you see it. Where is the? You can see: there are some... still cracks there. Andrea and Stefan estimate the value of the stove at 4,000 euros. Easily three times as many in restored condition. But the work will take time. About 40 hours if everything goes smoothly. At the Goslar iron foundry, the time has come: the iron is hot, 1450 degrees. The production manager, Andreas Jacobi, has to take the iron to the molds. With the so-called pouring pan. Now he still has to check if there is any slag residue on the iron. She is clean. Clean? Good. They have about 15 minutes.
Then the iron becomes too solid to be shaped. *rumble* *hum* The iron in the mold is already hardening. If it doesn't flow fast enough in all corners, there will be holes in the plaster. That I don't pour it completely, but pour it fast enough. stop on time. If you don't stop fast enough, the iron will flow over the edge. Then we burn... ...if we're unlucky. Yes. That was good. The small shapes are still missing. Also the deer image of the mold maker Walter Schulze. It's harder to hit. The smaller ones fill up faster. It's like shooting sparrows with a cannon.
The griddle should cool in the pans overnight. The thin-walled deer image may already lose its shape. I didn't go at all. It's okay, but it's okay. Dissatisfied. Because it was not filled. Here the whole corner is missing. But hey, that happens. Yes, quite bad. To a new one, they say. It's almost finished, the iron is still missing. If you don't arrive on time, they won't be able to meet the big ring delivery date. It's me. Do you know anything about pig iron? will come? Nothing yet. IT'S OKAY. As soon as they know something, they should call so we can plan.
Yes? Thanks god. The vendor declaration is the same. It's supposed to arrive tomorrow, but I don't know when. The statement was either today or tomorrow, it must be there no later than tomorrow, the only question is when. Oldenburg. Stefan Fuhrken has been in the workshop for the third day. The old cast iron stove top grate has to come off. And something else has to go: an old coat of paint. Throw away! It can be fixed? Yes? Excuse me. I want to know if it can be fixed. Yes, it can be fixed, but it is difficult. The color is...
But it looks different. But the small indentations, there is still something inside. Because we don't know what kind of paint, resin or whatever, has to be removed. If paint residue remains on the stove, it could stink when lit. Stefan has to be careful not to damage the surface. * Loud buzz * The surface is only polished with this twisted wire brush. Only minimally removed, really just the color. Cracks in the plaster cannot always be welded or filled. Here Stefan connects the old molds with a plate. Like a plaster. Sometimes you think to yourself: this can be done quickly, you can fix it quickly.
But the devil is in the details, and then hour after hour it's gone. Such a repair or restoration often takes longer than expected. Stefan Fuhrken is actually a trained businessman. At 32 he started over and became a stove installer. Andrea gave him the idea. I can show you something again. Would you take the record? Then we'll start putting it together provisionally. For more than 20 years they have shared a passion for old stoves and their history. You can see that in your feet sometimes. So you have a certain form that is reflected in the book. Here you can see: This is a model that uses the same feet.
From the ... Rendsburger HÃ¼tte. With industrialization in the early 19th century, the demand for hardware increased. The CarlshÃ¼tte in Rendsburg, for example, will soon supply pans, chains and weights to the entire north of Germany. Cast iron bathtubs and stoves become big sellers. Since the middle of the 20th century, more machine components have been cast. Higher wages and energy costs made cast iron products unprofitable in Germany from the 1970s onwards. Today there are still around 115 iron foundries. It's always a puzzle. Not everything is easy to read, you have to live with the fact that you don't always find out.
Stefan wants to know if all the doors and castings fit. Is working. Does it fit another way, the plate? Yes. It looks good. Yes. This is where it starts to tip. Yes. Then it starts to lean. Exactly, from here too. Yes. We have to fix that, otherwise it will look lopsided forever. It's not much, just a millimeter or two. 30 hours of work have already been invested in the restoration. The stove is thinner than expected. 6 am in Goslar at the foundry. The iron there. It was delivered the night before. Founders Ingo Wormus and Felix Krause fill the big furnace today. 4,500 kilos of nodular iron, that is, 4.5 tons. *Loud blows* Today, production manager Jacobi can finally throw the big iron ring.
If all goes well, it will look like this wooden model after molding. This is how you can make a huge wooden ring. Andreas Jacobi needs 1.8 tons of iron to fill the mold. Clamps and weights prevent the iron from pushing up on the top box. That the box drips, that it drips. You can't take any more. We can only see that nothing burns or anything like that. It is important that no one gets hurt. Then you have to be careful that nothing catches fire Two hours until the spill. Smelters can no longer leave the furnace alone, even during break. sausage soup From the slaughter.
This gives strength, is healthy and makes a slim foot. Felix Krause is one of the youngest here. The average age of men is almost 50 years. It depends on how the body reacts. Depending on how healthy you are. Chew first. Yeah. I think... Most of them... around 60... ...then most stop or even before that. It is hard work.It can go up to 80. Until it's no longer possible. I'll stay here until I can't anymore. time to pour. Today you have to be very careful. Protective suits protect against heat. They are about to cast a special iron: the so-called nodular cast iron.
One particularly flammable ingredient is already in the pan: magnesium. This causes the graphite to form spherical and not lamellar. Then the material has a higher tensile strength, it is more ductile, more flexible than gray cast iron. We have to hurry and see that the first mixture... We have a maximum of 15, 20 minutes for the ring to be cast. Because magnesium then disappears. All the ingredients are weighed. But the experience is also part of it. Caution! A sample should show how well they fit the nodular cast iron recipe. Sensors in the container measure the chemical composition. I have to see what comes out of the mix.
Everything has worked so far. Let's hope that what is supposed to come out comes out. It fits. Now: the big ring. Throw out, out! Otherwise I will spill it everywhere. Take it easy, Felix. Start slow. Now you can a little. Oh, that makes a babble. strip! It will soon be seen if the clamps and weights can support 1.8 tons of hot iron. Now it comes. Good! Look what's inside. For the copper. Looks great. It didn't pop or break anything. All gases go away well, did not escape anywhere. as it should be The ring has to cool in the mold for three days.
Back at Varel's villa with host Frank Walther. Today the old cast-iron stove is supposed to be burning again. The oven must be sealed everywhere and must be straight. It's straight. You can't do anything else. The chimney is crooked. Yes, after the fireplace you can not go. You can see how bent it is. It doesn't matter where you would place the spirit level. It can't be 100% direct, the whole thing. When you stand in front of the finished stove and get the feeling that it looks good... The eye should be satisfied. Yes? Can? Yes Yes. Stefan Fuhrken joins all parts with "iron putty".
That was also done 100 years ago. The putty hardens and seals the joints. The stove can only be relit in the villa. It falls under vested rights, a kind of special permission. Without them, Stefan would have had to completely rebuild the oven. You can't see the teeth of the mouse. Installing a certified combustion chamber in such a circulation furnace is almost impossible. Almost never, because nowadays these chimneys have to be a certain height. You can't put that in there. That does not fit, from the height. For Andrea, a stove is like a piece of furniture: it must fit into the room.
She wants to show how the stove works: It depends on the background. My husband is sometimes impatient. He always amazes me what he comes up with. He says, "Why do you have to try this now?" Because I have to incorporate that into the planning. Even during the construction phase. Let it go, you should take a look. The fabric is ruffled. do you have softer? It doesn't fall better that way. Yes Yes. Almost done, the oven is ready. Stefan Fuhrken wants to know if everything works. That looks better. We'll do it... ...like we used to do. A small boy scout fire.
The fire would now show us: is the chimney drawing well? Is there a column of cold air in the chimney? Is everything ok, is there an elevator? Work against the fireplace. It still lacks the right momentum. We may still have to... push a piece of newspaper through it. Don't use the old wallpaper! no *Whistle* Now you can hear it too. Now Wumms enters the matter. In fact: the smoke goes away! A fireplace that hasn't been used for a long time: Cold air accumulates there, like a plug in the chimney that needs to be removed. The easiest way to do this is to light a newspaper or two or something similar at the lowest point of the chimney.
And expels the column of cold air from the fireplace. done! The oven works. This is something special. My great-grandfather bought it and it stayed on the corner forever. He also survived, no one threw him away. It's working now, that's great. Great-grandfather is happy. The restoration took about 50 hours of work. It was worth it - the old oven was cast over 100 years ago, from cast iron. Today it is hot again, bringing warmth to an entire room. Copyright Subtitles: NDR 2022
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