A simply stunning work of art found at the Charles Luck building, 1111 34th St NW, Washington, DC, the larger version and additional photos of the pair of terracotta horse heads can be found here:
I strongly suspect these original pieces were largely hand sculpted, for the simple reason that they installed only one of these per stable building over the doorway. Obviously these types of terracotta pieces were made in a mold, but I am certain the ears were pressed separately in another mold and attached later while both the ears and the head were pliable.
That would totally eliminate a lot of issues with fragility of the moist clay being removed from the mold, and it would have greatly simplified the mold of the head.
The head is turned at such an extreme angle that it creates a massive hollow with deep undercuts between the head and the roundel’s concave area, I am betting that either the head was pressed separately from the roundel itself which could have been made with a template on a potter’s wheel in fact, and then joined together later when they were firm enough to handle but still pliable.
That building in fact where that roundel is, actually has two horse heads on it, and they face in opposite directions, they very well may have been hand sculpted one of a kind models rather than having been pressed in molds.
I can’t see that they would have gone to the trouble of molds when a building having a pair of these facing different directions was almost unheard of, I’ve never seen it done. It wasn’t like they would have sold 35 of these a year.
Most of the deep undercuts on these types of sculptures were hand detailed in later during final cleanup after removing from the molds, that also made mold makign much easier and a competant worker would have easily been able to add those few minors undercut details and details as necessary in just a few minutes.
They were all paid by the piece not by the hour, so you can see how that would have worked out perfectly for the terracotta firms, it wouldn’t have mattered if the worker spent an hour or six on a piece, they still only earned around 25 cents to a dollar per piece.
Both of these scenarios presents difficulties today in reproducing these works in anything other than pressed terracotta, because with plaster or cement you really for all practical purposes do not enjoy the ability to simply attach separately made parts like this, and with concrete being so heavy and very easy to break it doesn’t lend itself well at all to a piece like this. Plaster is marginally suited to casting something like this in one piece with free standing ears.
Modern rubber molds usually take care of those deep recesses and undercuts, but if they are severe then they might have to be altered somewhat on the original model to reduce or eliminate them to make mold making and casting practical.
So it would appear that the only really viable material for this type of a model would be pressed terracotta with the ears being attached separately.
In the 19th century when these pieces were made, they used water based clay and plaster to make the master original models, I’ve seen pictures, they generally used formed and shaped plaster for parts such as that roundel and then modelled the clay onto that still damp plaster base.
Once the model was finished and approved by the architect, they made a mold of it while still damp. They did not have the fancy mold rubbers we do today, so they made a plaster piece mold off the damp clay/plaster model and I suppose if they were careful they could pull an additional mold or two off it.
The original model was then recycled into the clay bin.
Making the plaster mold off the still moist clay eliminates issues with trying to pull plaster sections off that have undercuts- the model is soft and gives, in the same way my rubber positive casts discussed previously do.
A big issue with me is that in order for me to do that I’d have to make a mold of my still moist clay model in rubber, make a rubber positive and make a piece mold from that.
The trouble is, to fill a large bulk of a cavity such as this horse head has with rubber would likely take several gallons, and the material is $200/2 gallon kit. It would take a kit to make the first mold, two kits to make the rubber positive.
I’ve been thinking the other day about a sort of reverse mold to save materials, that is to say brushing on the Rebound 25 rubber on the inside of the negative Rebound 25 mold, and making the rubber very thick, maybe 1/2″ instead of the usual ~1/4″ and then filling the rest of the cavity with plaster or even self hardening foam attached to the rubber via keying so they stay together permanently.
Once that is removed like a casting from the negative mold the rubber and plaster “cast” would have rigidity from the plaster mother mold section, and yet, the 1/2″ thick rubber would be soft and have enough “give” that it would easily see plaster piece mold sections removed from normal undercuts on it.
That would save gallons of expensive rubber not making a large cast completely solid rubber.
It’s easy to see how this model will require a lot of advanced planning, the finished model would also be limited to my present kiln size 18 x 23