I recently had the opportunity to check out the Metropolitan Museum of Art’s Cast In Bronze exhibition, which runs through May 24.  I’m admittedly not the world’s greatest expert on bronzes, but this exhibit was FUN.  Why?  I took an artist with me.

If you’ve been following along, you may recall one of our special contributors is a friend of mine with a seemingly never-ending list of unusual hidden talents.  (Men!)  One of his less-hidden talents is that he’s an extremely gifted artist, and in particular, a sculptor. I highly recommend taking a sculptor to the museum as your personal tour guide.  Particularly if you can find a cute one.  (This last feature is unlikely to add utility to the exhibit itself given the presence of security guards, but I still recommend it from an aesthetic standpoint if you can manage it.) Since I’m guessing that might present a challenge for most people, however, I’ll do my best to share what I learned in my tour of the exhibit.

I have to admit, prior to spending quality time with a sculptor, I had some vague idea that bronzes were casts in some giant permanent mold that you’d just pour bronze in and then pop out the final product, shiny and new.  And then, you know, modern sculptors artificially patinated them, and the old ones were clearly patinated because they were old.  Uh, yeah. Okay, yes, I’d heard of the lost wax technique but for some reason it didn’t occur to me that the technique would be applicable to anything but jewelry.  Well, after touring this exhibit, I can say with confidence that the work is nowhere near over once the sculpting is done.  (The Man With The Hidden Talents kindly did not call me a moron, although I admittedly did not actually VOICE all of my original impressions of the process.)

So here’s how that process works.  First the sculptor creates the figure in terra-cotta or some similar material.  The terra-cotta is then used to make an initial  mold.  These days that’d be done in rubber; before rubber became such a readily available material, sculptors would have used plaster.  This is where one of the first major challenges would have come in.  Obviously rubber is flexible.  Plaster?  Not so much.  Despite the fact that plaster is not at all pliable once it’s hardened, the whole mold has to come off the figure undamaged, which can present a challenge if the figure has undercuts or is otherwise complicated.  Sculptures that were sufficiently complicated were often cast in several different pieces that were then welded together, and the plaster mold for each section could sometimes look like a jigsaw puzzle, cut into as many different pieces as were necessary to make it possible to get them all off the terracotta intact.  Several of the pieces in the exhibition were clearly done in several sections and then subsequently welded together.

Once the plaster mold was done, it would be used to create a wax figure.  At this stage, because wax is relatively easy to work with, a series of branches called sprues are added to the figure running from the lower points of the figure back up to the top.  The idea of the sprues is to create tubes in the next stage mold so that the bronze will be able to flow all the way through the smaller parts of the mold rather than flowing down and getting air trapped in the cracks and points.  The wax is then used to create a ceramic mold (with layers of a sort of thin liquid clay), the wax is melted out, and then the bronze is cast. The ceramic mold ideally has to be fairly hot so that the bronze will flow all the way through rather than cooling too fast as it hits a cold mold.

A little visual of this part of the casting process is available with this piece:

Not only is the finished statue on display, but the Met has also included an unfinished cast of the same statue with all of the sprues still intact.  I highly recommend taking a look at it — it looks like the statue is trapped in a complicated bronze basket, and shows just how much work is still required to finish the piece after the initial casting.  The technique as a whole is apparently so good at transferring detail that it can even transfer fingerprints in the wax to the final bronze.

Once the piece is cast, the sprues are removed, any seams or other imperfections polished out, and the piece is patinated. These days that’s largely done with commercially available chemicals, but apparently historically that process sometimes involved burial in a pit with ashes and exotic goat byproducts.  (Ah, the romance of being an artist.)  A wide variety of finishes can be achieved with different substances, from greens and browns to a cherry red, and shiny or entirely matte.  My personal favorite was a faintly reddish shiny patina that gave an impression of depth in the patina as if there was a layer of lacquer on top.

Unfortunately, the Met hasn’t included pictures of several of my favorites on their website, but I recommend taking a look for yourself.  My favorites included a series of the Roman gods by Michel Anguier, including a handsome and dynamic “Agitated Neptune,” who did indeed appear to be in something of snit. Pluto, on the other hand, just seemed to be morose.  Personally, if I had Cerberus making like he was about to bite me in the butt like that, I’d be a lot more than morose, but I suppose if I were a god I would take these little things in stride.

Lest I start thinking of myself as an art expert, however, the exhibit smacked me down in one of the later rooms.  One of our less dignified and artistic moments took place in front of this figure:

It’s a nice piece, but both of us looked at it and promptly said “That’s not where the liver is, is it?”  The Man With The Hidden Talents then whispered “I think we’re dorks,” and we took our science geekiness and slunk away to the next figure.

Hey, at least I know how casting is done now!

Tags: Cast in Bronze, Metropolitan Museum of Art, sculpture

This entry was posted on Tuesday, March 10th, 2009 at 8:18 am and is filed under Upper East Side. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.