• Minervalaan part 4: Carving the figurines in limestone

    After we had reconstructed them with plaster, we were about to start carving the eight figurines from the Minervalaan into new limestone. The new stone soon arrived. I was not involved in the stone selection for this project, but it ended up being Muschelkalk limestone, a material I was already very familiar with since the flying buttress figurines for St. Eusebius's Church in Arnhem (the Netherlands). Read here more about these figurines.

    Contour sawing machine

    the Sower of Spring cut out. Even with so few shapes visible, this already provides a lot of information about the parts

    Whenever we start sculpting in stone, we usually first rough out these kind of sculptures with the copying saw or contour sawing machine, and that was no different here. This machine is a manually operated saw arm with a feeler disk, with which we can relatively easily copy the outer contours of a sculpture. This machine cannot cut all the details, because its cutting disc is 400mm wide and doesn't reach into the deeper parts, such as the inside of an arm. Yet this saves an tremendous amount of work, because the large mass surrounding a sculpture can be removed quickly and accurately. I'd hate to think about having to cut away all the excess stone with just an angle grinder, or with a pointed chisel and hammer. Removal is not the only problem, but it also involves a lot of measuring work. And cutting with an angle grinder is heavy, dusty and noisy work. Not my hobby.

    Milling with a robot?

    carving 
 coat of arms on sandstone griffin with baroque shield
    hand crafted

    You might think: Why not just take a CNC robot, and accurately mill everything away with a robot router?? Nowadays the computer is the panacea for all problems. Artist? Project? Shaping the forms? Step 1: the computer. What an impoverishment. So much is possible other than just the computer. Take a look at old crafts. In addition, for me, a robot has several disadvantages. First of all, I would no longer be a sculptor, but a computer programmer. It would also mean that I'd have to face quite a steep learning curve to master everything: scanning, 3D operation, toolpath instructions, etc etc.

    Disruptions and duration

    slave to the robot

    Secondly, these machines are very expensive and prone to failure. The investment will need to be recouped, so you'll start looking for all kinds of work for the machine, and before you know it, you'll be working for the machine instead of the other way around. But most of all, a precisely milled sculpture doesn't make sculpting in stone any more fun. It'd be very boring to just rasp off the last millimeters a bit. All creativity is lost.

    You'd also have to be very careful during the reconstruction phase, because forgetting to fill a hole somewhere on your weathered original sculpture means that it will also be reflected in the end product. The same applies to the digital 3D model: if a hole is overlooked somewhere, the

    image: Mastec CNC Laser on YouTube

    milling machine will simply hollow out the statue for you, entering via that hole. Finally, CNC, with all its preparation time, is not always faster than a simple manually operated machine. Its benefit lies mainly in serial work and very complicated pieces. And that actually happens very rarely in our line of work. So let me just carve away the old fashioned way. It's nice that the contour saw can remove a lot of unnecessary mass.

    Upside down

    upside down they're a lot more stable for machining

    Anyway, so we contour sawed the sculptures on the copy saw machine. This time we turned the figurines upside down, because the foot end side offered too little support, but the top did. Makes no difference to the machine. We cut it out in three courses: thick slices first, well away from the final 'skin’ of the figurine, then slices of 1 cms wide, and finally a very precise milling pass, 3mm removed from the final surface. So once we really start sculpting in stone, there will still be some material left for the chiseling part.

    Minervalaan sculpting in stone: copy image Spring. Contours cut.
    Jelle has just started sculpting The Spring here. The saw marks from the contour sawing machine are still clearly visible

    Details carving and measuring

    As mentioned, details like eyes, nose and hands are not copied in the cutting process, but there are plenty of landmarks that a good sculptor can easily use to recreate the statue.. And then it's a matter of looking, comparing, measuring, mainly with compasses, and bringing back the atmosphere of the original.

    Compasses and templates

    Jelle with The Summer

    I don't really know what I should say about this, except that this is the most intensive part of the job, and at the same time the most fun. We're really sculpting now, shaping it. With the combination of the sculpture saw machine and measuring with compasses and templates, we can arrive at the final shape of the sculpture much more quickly.. This way we can quickly focus on the design, the expression and unique shapes of the chisel strokes.

    Pointing machine

    pointing machine with wooden cross and brass needle

    Traditionally, the measuring work was done with a so-called 'pointing device', a hinged brass instrument with a pointing needle, with which one can precisely pinpoint 1 exact point on the model, and when the whole contraption is next transferred to the block of stone, that one exact point can be precisely drilled to the correct depth. Extremely time-consuming work. These pointing machines are actually the ancient version of the robot milling cutter. You do have to pay very close attention, but it's not really inspiring. That is why this preliminary work used to be done by lesser sculptors. Read here an interesting article about this device and watch the videos about its operation.

    Muschelkalk limestone and light

    While working, it became clear to us once again that the choice of stone has a major influence on the appearance of the sculpture. The large shapes of the figures and especially the hair of the ladies were ideal for this coarse German Muschelkalk limestone. The sculpture's shapes worked well with the light and yet proper detailing was still possible. Unfortunately under the roof, especially with the wind cloths around it in the winter, there are often less than ideal lighting conditions. It all quickly becomes a bit flat when the light is filtered by dust, acrylic plates and scaffolding cloth. We often move to the square outside the shelter for assessment and photos. We were very curious about what it would look like on its final location!

  • Minervalaan part 3: reconstruction

    Searching for the right shapes

    In the previous two articles, here and here, I explained that the eight statues we've taken down from the Minervalaan 28-30 arrived in a very battered state. There ware several serious fractions and sometimes quite a loss of detail.

    In addition, in the distant past they had already been repaired with a very hard mortar, which had started to detach from the surface in many places. The multiple paint layers didn't help this either. Time to repair them and make a reconstruction before we were going to carve the copies.

    ← Detail of the image Winter.
    Old repairs and rusty iron staples are clearly visible on the eroded pieces of of its surface
    .

    Glue-up

    In particular the right hand Faun, the lady of Autumn and the Diggin Man of Winter came down in several pieces. Pressure from the building that rested on it and seeping rainwater will probably be to blame for this.

    Because these sculptures are not going to be restored, but will be copied, glue-up was not a complicated matter in this case. Just gather up all the pieces, find out how they fit, fill the fracture surfaces with glue, and clamp them right up.

    Moisture transport

    Now this is not something you can do anywhere. Suppose a sculpture is to be reinstalled in an outdoor environment, then you'll be dealing with moisture penetrating it. That moisture will eventually have to come out again, and it will follow a transport process from top to bottom and from the inside to the outside. Should it encounter a full dense glue layer on that journey, then problems will be guaranteed.

    Over a horizontal glue surface, for example, the moisture above the glue will remain within the stone for a long time, and it's difficult to get it out sideways. The result will be a strong deterioration of the stone above the glue layer, especially in a frost period after a wet fall or winter. So what we have done here with saturated glue surfaces was only possible because these sculptures are no longer placed outside.

    Old repairs

    After the bonding we started looking for the original shapes of the sculptures. In some cases this meant that we had to remove large chunks of old repairs. Sometimes too much material had been applied, which particularly ended up making legs too plump, with thick edema ankles. Not all repairs have been removed; we also counted on it that we would be carving a lot of details in the major volumes later on, in the phase of sculpting in the new stone.

    If you'd remove all repairs, that would also mean a loss of information, all the more so since it irrevocably comes off only while taking a layer of the original sculpture with it. The underlying stone is much softer than the tough cement repairs that were often very much stuck onto it.

    Shedding its skin

    Not all repairs were stuck on that much. Due to this barely permeable repair layer, and especially in combination with that dense layer of latex paint, moisture was building up within the underlying tuff. As mentioned in the previous post, there was a rainpipe hidden in the facade on the right façade corner, which dripped its moisture into the statuettes for years.

    The result was rich algae bloom, peeling skin of the statuettes, and, in the case of the Man Sowing, a total crumbling of the surface. I already mentioned that for this reason recovery was no longer a solution. The repairs would one day, in the future, just come back down, underlying stone and all.

    Photographic material

    For carving a good reconstruction in new stone, it was necessary to have usable models, based on the old statuettes. In this case we repaired the sculptures with a soft type of plaster. For this, I first collected as much photo material as possible, in particular from the sculptures on the other side of the street, which were in a much better state. A year and a half earlier I'd also taken a lot of photos of the views of each statue : from the left, left front, front view, front right, and right.

    I first printed and laminated these photos on A3 format, but those big prints were very awkward to handle. I discovered that a small book with all views in size A5 was much more convenient: because you can quickly browse through those. Ideally, these booklets would be printed on plastic, so that they wouldn't be susceptible to moisture and rain, But luckily paper also worked.

    Who does what?

    Jelle and I took on the reconstruction of three statuettes each. Jelle the ladies from Spring and Summer and the left Faun with a goat, and I the Digging Man of Winter, the lady of Autumn and the right hand Faun with his deer. Tim enthusiastically started working on the old woman of Winter and the Sowing Man of Spring.

    Plaster needs to set between the layers and we also needed time to assess the right shape, so this was work that we undertook in phases, sometimes in addition to other projects of sculpting at the same time.

    Loss of information

    During such a reconstruction you will always be faced with puzzle work when sculptures are so weathered. Details are no longer easy to trace back and you need to make choices. Which version is correct? That what we think to recognize here on this statue, or what is still visible on the other side of the street? It became clear that earlier restorers have not always known it either. Flat circles turned out to be the sunflowers of the Summer, and vague lines became ears of wheat or bunches of grapes.

    We noticed that the four Muses of the seasons also depicted four phases of life: the young girl stands for Spring, the young woman for Summer, the mature woman for the Fall and the old woman for the Winter. Each had their own attibutes: flowers for Spring, ears of wheat and sunflowers for Summer, vines, grapes and apples for Autumn, and a cloak for Winter.

    The lines of their hair also started to become much more defined as soon as we patched up the missing pieces: they continued into the facade.

    Tim's Man Sowing

    I've already mentioned it a few times before: the Man Sowing was the worst case. There was actually no recognizable detail anymore at all, and after dismantling even less was left of it . Once crumbs are still hanging on with their last edge, just a touch would be enough to lose those as well. But we already knew that in advance, hence all those photos.

    Now in addition to his work for me Tim also works as a volunteer at Museum De Dageraad, where everything can be found about the buildings of the Amsterdam School. And what do you know, he just happens to find the original plaster model of our missing sower hanging there, on the wall!

    To make a long story short: he was allowed to borrow it for his reconstruction, and in return, he suggested that he would restore this plaster model (which he did beautifully and in a careful way!) and then, based on this plaster model, he was able to reconstruct the entire tuffstone Sower again .

    The Man Digging

    I myself had taken on the reconstruction of the Man Digging from Winter. He was missing his lower legs, the clogs and the shovel, and other details had become very unclear. However, the upper body was still so sharp that the original chisel strokes of Jaap Kaas still reappeared from under the thick paint layer.

    This showed that the sculptor had finished his statuettes at the time with various chisels: the round chisel, the claw chisel and various flat chisels. This would give us guidance later during the sculpting in stone.

    The Man Digging had something else that was unclear next to his shovel. It looked the most like a continuous beam with a jumble above it. After studying all the photos, I thought it could represent a bare tree, which is being planted by Man Digging.

    Gallery: reconstruction of all figurines step by step

    After this repair round an inspection followed. Once everything was approved, we went on to the next phase: carving them into new stone. Read more about this in the next blog post.

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