Fibreglass in Furniture: Original Shells and Reissues
In the early 1950s, the fibreglass shell made it possible to mass-produce one-piece seats that were light, strong and comfortable, where moulded wood had shown its limits. These shells are sought after today, but the market mixes original fibreglass pieces with polypropylene reissues that look similar. For a buyer, it is useful to know how to tell them apart, how a shell ages and how to look after it.
The Eameses' research
The history of the fibreglass shell is tied to Charles and Ray Eames. Their research into moulded seating, first in plywood and then in metal, led in the early 1950s to a glass-fibre-reinforced plastic shell produced in series. Its manufacture for Herman Miller was entrusted to a specialist maker, and the seat became one of the first plastic-shell pieces of furniture made in large series.
The principle is simple: a single moulded piece follows the body, without upholstery, in a material that is both supple and strong. The shell fits on various bases (wire base, wooden legs, swivel base), fixed with rubber shock-mounts that absorb stress. In Europe, Vitra produces these models under licence today; in the United States, they remain associated with Herman Miller.
Original fibreglass or reissued polypropylene
This is the most useful distinction. For decades the shells were made of fibreglass. Reissues then used polypropylene, an injection-moulded plastic with a smoother look, before fibreglass was reintroduced on some production. Both materials make good seats, but they look different.
An original fibreglass shell lets the fibres show through: it is slightly translucent and its texture catches the light. Against the light, or when you tilt it, you can see the network of fibres set in the resin. Polypropylene, on the other hand, is uniformly opaque and smooth. To the touch, fibreglass is harder and colder, polypropylene warmer and slightly flexible.
The "zenith" rope edge
On the oldest shells, the rim forms a rounded bead, like a rope running around the edge. It is called the "rope edge" or "zenith" edge, after the maker of the first shells. This rolled edge, a result of how the first series were moulded, is a sign of age that collectors value. Later production has crisper or reworked edges.
A zenith edge is not enough on its own to date a piece, but it deserves close attention, together with the markings and the shock-mounts.
Ageing and repair
Fibreglass ages well on the whole. Its weak points are chips or cracks after an impact, and wear on the rubber shock-mounts that join the shell to the base. Over time, these mounts harden, crack or come unstuck. Replacing them is a routine job, as long as the right adhesive is used so the shell is not damaged.
On the surface, an original shell may show fine scratches, a matt haze or signs of use. Gentle cleaning with soapy water is enough; abrasives should be avoided, as they scratch the resin and pull out surface fibres. A restorer can sometimes stabilise a crack or chip, but a shell broken clean through loses value. Replacing the shock-mounts, on the other hand, makes the piece usable again without affecting its authenticity, as long as the shell itself is original.
Buying a vintage shell
Look first at the material (translucent, textured fibreglass rather than smooth polypropylene), then at the rim (a possible zenith edge), the markings under the shell, the condition of the mounts and any cracks. An original shell in good condition, on its period base, sells for clearly more than a recent one. A cracked shell, or one remounted on a different base, should be described as such.
What we check
When a shell comes through our hands, we examine it against the light to identify the material, then look at the rim and read the markings to place the production, on the Herman Miller or the Vitra side. We check the shock-mounts, replacing them if needed and saying so, and look for chips and cracks. Our photographs show the texture of the shell and the condition of the rim.
By
LAPIERRE MARKET
