m. arch i
history of building technology
professor richard cleary
the university of texas at austin
m. arch i
history of building technology
professor richard cleary
the university of texas at austin
Corian, also known generically as “solid surface,” is a relatively new product with respect to the entire history of construction materials and technology. As outlined in its patent, “solid surfaces” refer to materials that are an acrylic resin “filled” with finely ground minerals. In layman’s terms, this means Corian is a combination of mineral and plastic – part synthetic, part organic. For example, the product is most widely used in bathroom vanity tops, sinks, shower stalls and kitchen countertops. Furniture, sanitary use, lining materials, and various articles such as office supplies and store fixtures have also been constructed out of solid surface materials (Schober).
Due to this relative newness, there are few established precedents on how to use it and what to use it in other than what is outlined in its patent. When compared to materials such as masonry or wood, it is perhaps understood that there are established means and methods to accomplish a design task with these materials. Because of the amorphous nature of Corian, such methods may be seen as less apparent. In this essay, I will examine the history of Corian, it’s composition, its niche in the built world, fabrication methods, and various design exercises with the material.
In 1963, Dr. Donald Slocum, as a part of the DuPont Chemical Company, set out to create a material that is non-porous, antibacterial, stain, chemical and fire resistant, solid all the way through, void of air bubbles, hard enough to be used as a work surface, easily repairable, has a consistent pattern and color, is workable with standard shop tools, and is of course pleasing to the eye. In 1968, this material became the patented property of DuPont – Corian. Shortly thereafter in 1971, Corian was introduced to the public as a commercially available product at the National Association of Home Builders exhibition in Houston, Texas (Busta). One aspect concerning its introduction at the exhibition is that the product was only available in a slightly off-white or eggshell color. Because of this and its antibacterial qualities, viewers of the product assumed that Corian was intended for architectural situations in which white was the norm; therefore, it was initially relegated to kitchens, bathrooms, and other places where visibility and sanitation was paramount. This point is further solidified by the fact that additional Corian patents even today consistently reference these sterile surfaces as places the product is frequently used (Yablonski).
When the product was first released, the original mixture used to be approximately two-thirds calcium carbonate filler and one third acrylic resin, or poly methyl methacrylate (PMMA). Although, the use of calcium carbonate is what gave corian its matted white finish, it was also inhibiting the product as it was prone to “fading” or “whitening” and scratches. This is initially what limited the product to white at early stages. Then in 1970, Ray Duggins, another researcher at DuPont, replaced the two thirds proportion of calcium carbonate with a two-thirds proportion of alumina trihydrate filler or ATH, which comes from Bauxite Ore. For reference, alumina trihydrate is also used in products like tin foil and antacid medicine due to its basic pH level. The switch in chemical composition was quite fruitful as it gave Corian resistance to every acids such as lemon juice and kitchen cleaners, and gave it the unique matte translucency the product is known for today (Lasell).
Due to the fact that Corian was patented upon invention, there was a general lack of deviation from the simple white surface. However when the patent expired in the late 1980s/ early 1990s, the number of other companies producing a generic version known as solid surface exploded. Some of these generic lines include LG HI-MACS, Formica Group Solid Surfacing, Aristech Avonite, EVO surfaces, Samsung Staron, Lion Chemtech TRISTONE, and so on. The resulting competition fueled new ranges of the product that investigated different surface effects. From 1984 onwards, there was an exponential increase in variability, color ranges, and effects in the world of Corian and solid surfaces. At DuPont, the color initiative was led by Gin Guei Ebnesajjad. Through newly available technologies for variable distribution of the alumina trihydrate filler, and computerized systems for uniform color reproduction across many samples, the color palette grew to about 72 different colors by 1994. From here there was nowhere to go, but up – to constantly produce more and more finishes. Below are several lines that specifically DuPont came out with respect to their release year.
In 2002, the Corian Private Collection was released. This line features random patterns and some non-repeating. The intention of this line was to resemble certain natural materials such as stone (Lasell).
As you can see, Corian and solid surface has had a short yet diverse history up until now. This diversity will continue to compound as long as companies in the solid surface industry continue to patent new finishes, and old product patents expire resulting in accessibility to more people. I can see a future in which the range of finishes are so diverse that it becomes as vast as a library of carpet finishes in an interior designer’s library. One might say it has already reached that point.
The place Corian holds in the built world today is more ambiguous than it used to be. As said before, the product was initially understood in the context of sanitary environments such as kitchens, bathrooms, and hospitals. In this realm, how does it compare to other countertop finishes such as granite, quartz, stainless steel and so on? The below chart compares the most commonly used materials.
From this chart, it can be seen that Corian provides more flexibility in terms of where it can be used. It can be used for coves, backsplashes, and integrated sinks (meaning the sink is the same material as the counter) – something no other material can do at the same price point. While it is fairly easy to get each material in different colors, it is much easier to find consistency of color in Corian given that it is a man-made product. Another strength Corian has is its workability where one slab meets another, which is important as it comes in small thirty inch wide slabs as opposed to the immense sizes stone counters come in. Because the surface can be sanded down, the seams are inconspicuous.
In comparison to quartz and granite, most interior designers I have had conversations with have said that Corian is generally considered a less durable and marginally cheaper option. Generally speaking, granite and quartz are more resilient when considering heat, stain, scratch, and chemical wearing. This is especially so for heat considering that it is used to mold Corian into shape in the production process.
While solid surfaces are prone to cutting and cracking more readily than its stone counterpart, Corian can be easily refinished. In principle this is fantastic, however, on the consumer end these flaws are often left festering – diminishing the most often cited reason for using Corian. This reason being its antibacterial quality. In the practical frame of discussion, it is better to go with the longer lasting stone materials. So, Corian is by no means an all encompassing product to solve all consumer problems. It is merely another material whose use is to be determined mainly by personal preference.
Taking a step back from the practical usage of Corian as a sterile surface, understanding its niche in terms of the material spectrum is important to unlocking its use in other realms of architecture and design. Restating the fact that solid surfaces are part natural and part synthetic, it fits right in the middle on a scale between stone and plastics. Its material blend between these two boundaries lend itself to the sturdiness and workability of stone in tandem with the moldability and flexibility of plastic. The final product is essentially a “premium” feeling plastic or a “regular” looking stone. Regular meaning void of discrepancies that occurs across slabs of stone. Its status as the halfway point or middle-ground material implies the possibilities of interesting “halfways” in construction techniques (“Corian Super-Surfaces;” “Material World”). In order to disambiguate Corian from this “neither here nor there” material, the next section will investigate these techniques in order to imply how it can be used and what it can be used in.
CNC (Computer Numerical Control) Milling
CNC milling is a essentially a computerized method of stone grinding or wood shaping. This method makes use of bits or cutters to shape solid surfaces. On the next page, is a diagram illustrating several different types of cutters.
The end mill cutter is a cylinder that is optimal for cutting out pieces in Corian sheets. It is also good for geometric patterns on the surface and in low-relief. The spherical cutter, due to its rounded head, is good for curves and wavy forms both in terms of patterns and relief. Next, the disk cutter is useful for creating large sweeping linear patterns and reliefs. Finally, the gray-scale cutter is essentially a smaller and therefore more precise version of the end mill cutter. This CNC bit facilitates very close machining, and can be used to create extremely fine structures, all the way to interpreting a grayscale photo and cutting it in relief, hence the name “gray-scale” cutter (Noe).
Because Corian is relative to plastic in terms of its one third acrylic composition, heat is its weakness. However, this weakness to heat can be used to mold Corian into forms other than the flat rectangular sheets it comes in.
To mold Corian via thermoforming, one must first make a mold upon which the surface can be shaped. Typically, these molds are made with medium-density fiberboard and plywood due to its low cost and isotropic quality. To reduce wrinkling when molding deep shapes, a male-female mold relationship is required. For example, a concave surface requires and male mold, and a convex surface requires a female mold.
Second, the Corian sheet is cut to slightly over their required dimensions for the final product. After cutting, all the material then needs to be sanded to a smooth matte finish with any chips and scratches removed from the edges.
Third, this trimmed “blank” piece is placed in an oven to heat up and induce flexibility. The temperature, and amount of time it takes to properly heat up the blank piece depends on a variety of factors including its size, thickness, shape, surface area, and intricacies of its mold. As a general rule, the temperature is not to exceed about 400°F or 200°C, as the surface of the Corian will heat up too quickly, and then burn. Tests are typically done at this stage.
Once heated and malleable to a leather-like flexibility, the fourth step is to take the blank out of the oven, then fifth, place on the mold. Once positioned, the piece is placed in a vacuum press to hold the Corian tightly on the mold as the sixth step. There is no specific amount of time to keep the surface in the vacuum press, but the material should be kept constrained until it cools to about 180°F or 82°C measured at membrane surface, then release it to reduce stress. Seventh, take the Corian and trim off the excess by hand or power tool. For the eighth and final step, take the surface off the mold, and the Corian piece is formed (“Thermoforming Corian”).
Seaming Corian means to join two or more panels together. When seaming two surfaces, the most utmost goal is to create inconspicuous seams to maintain its monolithic quality. The best method for joining two pieces is the “router pull-through” method. To accomplish this, one uses a double-fluted router bit that is passed across the connecting edges of both pieces at the same time. Once this is done, the surfaces should be cleaned with a white cloth or paper towel and denatured alcohol. Next, the pieces should be placed about one-eighth of an inch apart and have a dam on each edge so the adhesive does no overflow. Place glue in this gap to approximately half full to reduce excess when the sheets are pushed together. The glue that is used is typically from the solid surface manufacturer, and is a liquid form of the solid surface material itself. Once together, clamp using a vacuum clamp or glue small blocks of plywood to each piece with hot-melt glue and clamp these with conventional clamps. When the adhesive is dry, the excess should be removed. It can be removed by using a number of methods such as using a router on skis, orbital or hand sanding, and chiseling off the excess (“…Seaming.”).
From 1995 onward, DuPont started an initiative to promote Corian in design. DuPont would subsidize sheets of Corian, or give them to designers for free to create whatever it is they thought they could do with the material. This was a result of wanting to push the product away from usage in solely bathrooms, kitchens, and other environments where sterility is important. Effectively, the company was looking to expand the market for Corian (Lentz). They were successful. In this section, the way designers have interpreted its construction techniques and the material itself will be examined across projects at many different scales .
The corrugated ruler by Erdem Selek is a small scale design exercise that manifests itself almost exactly like a male and female mold when forming solid surfaces. The design of the ruler is indicative of how was produced. Each ruler is a thin piece of Corian thermoformed to have either concave or convex ridges for the measuring increments. The sheer thinness and size of the ruler itself is a testament to the moldability and durability of the material at small scales (Tucker).
The Una table is a project designed by John Beckmann and David Serero. Beckmann and Serero chose solid surface for their table because it has a simultaneously highly refined modern feel and timelessness with its mechanical resistance and weight of stone. They were also interested in dual nature in that “it’s as soft as ivory and very organic” (Yablonski). When designing the table, they were particularly attuned to the material’s thermoforming capabilities in creating dramatically draped surfaces that also give it structural stability (Galadza).
Corian Screen / Railing
Marc Fornes of the design firm The Very Many, is known for leveraging digital technologies and fabrication methods in his designs. For his project that created a railing out of Corian, Fornes made use of 5 axis CNC milling to achieve very tight angles and sweeps. According to Fornes, the project benefited from the fact that Corian is a forgiving material, which can be easily sanded to eliminate flaws and joints. However, the unexpected weight was the biggest challenge of working with the material. Fornes states that “in a project where the design objective was ‘to create a screen that appears light, maintaining the airiness that characterizes the rest of the apartment.’ Ingenuity was required to disguise the weightiness of the material”. To stabilize the milled surface, it is connected to the wall at the top of the stair, but as it descends, it becomes two-sided, and plays with variation in thickness and cell density to make it appear light and porous. It is important to note that Fornes specifically mentions that the railing is unfinished as it is already soft to the touch. This is a testament to the product’s level of refinement, and perhaps why it is seen as a futuristic or modern material by designers (Gintoff).
In 2004, Ron Arad experimented with the translucent property of solid surfaces in “Lorez-dolores-tabula-rasa.” The exhibit first opened in Milan and used fibre optic technology to turn white sheets of Corian into low resolution displays for videos, hence the name of the installation playfulling obfuscating the screen and blank slate quality of Corian. By CNC milling a matrix of low relief holes on the concealed side of the solid surface, Ron Arad creates an invisible texture to the onlooker that also functions with an experiential quality (Lasell; Allen).
Motel One by Mackay + Partners in London is the first Corian-clad building in the United Kingdom. Similar to what Ron Arad did, Mackay + Partners created a solid surface system with etching and embedded LED lighting in each panel. The result is that the building can change color during the night through these punctuated etches. This creates a playful dichotomy between day and night. During the day, the building is an unassuming, white, monolithic piece, but during the night the facade reveals a hidden world of intricacy and detail as a gestural way to keep with the general vernacular scale of brick so prevalent in London (Turner; Dheere; “Minories Hotel London”).
Seeko’o, which means “glacier” in Inuit, was the start of a monolithic concept for Atelier King Kong in designing the Seeko’o Hotel in Bordeaux. In order to create this glacier, the architect Jean-Christophe Masnada chose solid surface for the building’s exterior cladding. In terms of details, the facade uses an aluminum framework that includes invisible fixings that attach to the back of each Corian panel. This gave the surfaces extra strength as they were very large, thin panels. In each frame, Masnada also put insulation and a rain-proof film to provide the building with protection from the elements – the skin became an all encompassing system for architectural and practical necessities (“Corian Panels…;”“A Facade Made Entirely from Corian;” Stacher).
A Gust of Wind
“A Gust of Wind” is a project by Paul Cocksedge for the London Design Festival in 2010 at the Victoria & Albert Museum. This particular installation features three hundred curled pieces of Corian. Each piece was thermoformed into progressively more and more curved sheets and then suspended or affixed to the ground to freeze a moment of paper blowing in the wind. In this installation, Corian was used almost as an ironic expression of the paper. While paper is light and can easily be blown away, solid surface is deceptively heavy. Functionally, Corian was also used for its durability. If paper was used, the exhibit would have been susceptible to “denaturation” over time (Etherington).
The Peacock Chair by UUfie is an artistic piece of furniture design for the Design Miami exhibition in 2013. The chair is made from a singular sheet of Corian that was slit on a CNC machine to create a lattice. This lattice was then heated up and stretched apart in a thermoforming process to curl around at the bottom to form the seat and spread apart at the top to form the back. This chair is particularly striking as it pushes the limits of the material’s mechanical resistance. It is important to remember in this case that Corian is particularly heavy – like stone – and because of its hybridity between stone and plastic, it is able to hold itself in tension to create this dazzlingly thin and intricate structure (Quah).
plusClover is an architecture firm based in Hong Kong. Two projects they are particularly known for are two installations, one called Yud Yud (left)and the other called Immuring (right). These two projects both use Corian and an understanding of its construction techniques to create new design conditions. In the case of these two installations, the idea of chamfering the connection between two sheets of material is particularly notable. What the firm did to accomplish this was rather than join two pieces flush and then create a reveal, the panels were joined at angles so that they are only partially touching. This method creates more pointed and directional surfaces as it allows for sharp cliffs and valleys. CNC molds were also milled to act as a jig to mount the pieces together. These two projects play up the ironic nature of the monolithic, carved stone aesthetic that Corian often takes as its construction is generally an additive one at larger scales. This irony is continued through the chamfered and low relief expressions that give way to a concealed backlight glow (Anastasiadi; Lee; Lee).
While Corian comes in a multitude of colors, there is a seemingly interesting trend of designers sticking with the white version of the material. Perhaps there has developed a certain nostalgia for Corian in its kitchen or bathroom form, and abstracting that nostalgia to a new form lets one reflect on their own experiences with the material. Maybe the slick and translucent finish speaks for itself. By feeling the material, one gets all they need, thus making color just an unnecessary extra as in the case with Marc Fornes. It could be that designers tend to prefer the simplest form of a material. As expressed in Ron Arad’s “Lorez-dolores-tabula-rasa,” the white form of solid surface is a blank slate upon which to work. Or it could be that the original white Corian is what DuPont subsidized or gave away to designers. Whatever the reason may be, it is undeniable that solid surfaces are an extremely versatile material.
The versatility is on par with that of plastic, but the heft of the material gives it more substance or perceived quality as plastics are often seen as cheap due to their lightness. Putting Corian in the category of “heavy” plastic seems ideal at first, but that would discount the more telluric quality the mineral filler brings. What’s more to this is that Corian reads differently at different scales, even within the same design. Overall the Corian could read as stone, but when zoomed in, become more plastic, such as the case with Seeko’o hotel where the panels lead up to a monolithic whole I think that it is perfectly fine to let Corian sit between stone and plastics ebbing and flowing between the two depending on how a designer uses it. The ambiguousness of where it belongs allows for more interpretation and play in making.