Clamshell Box with Interior Shelf and Scavengers for Fragile Metal Object
Photo Credits: Emily Brown
Illustrations: Emily Brown
This housing was made for an oyster shell and pearl set into a delicate gold, silver, and gilt-silver mount (figure 1). The resulting design was a clamshell box with a drop-down front and two front flaps with rare earth magnet closures. This box held a tray for the main component (the mounted shell) and a shelf that could support two boxes containing the smaller gold hinge and shell (figure 2). The design and materials took into account the need for ease of use, a minimal footprint for storage, the ability to scavenge for airborne pollutants, and the ability to transport via hand carrying in a vehicle.
Materials, Tools & Supplies
Corrugated museum blueboard
Hot melt adhesive
Closed-cell polyethylene foam (i.e. Ethafoam and Volara)
Flashspun high-density polyethylene fabric (i.e. Tyvek®)
Tarnish preventing fabric (i.e. Pacific Silvercloth®)
Loose weave cotton fabric
Rare earth magnets
Clear polyester sheeting
Scalpel or box cutter
Low tack painter’s tape (i.e. Blue tape)
- Sketch it out: Sketches of the proposed design were drawn, which served as a guide to gather materials and visualize construction and final product. The sketches in figures 1 and 2 illustrate key design features of the clamshell box with a drop down lid and two front closure flaps, interior shelf, the placement of two boxes and one tray, rare earth magnet closures, the position of the main component within the space, and placement of foam padding to support main component.
- The minimum interior dimensions required to safely store and support the object were first determined, and a schematic of the flat boxes was drawn. The author determined a standard size for the two interior boxes and one tray (figure 5 and 6 in green).
In this case, the standard corrugated museum board used adds an additional 1/8”+ thickness on these dimensions depending on the design. This dimension was added for each folded edge (figure 5 in red). The dimensions for the lid were calculated last, and were determined by the total dimensions for the interior footprint plus total thickness for the board (figure 6 in blue).
- Constructing interior boxes and tray: The two interior boxes and one tray were measured and marked in pencil, then cut and folded. Joins to be folded were first creased with the edge of a bone folder guided with a straight edge. Flaps extending from the front and back sides were folded and adhered to the exterior of the right and left sides using pH neutral EVA adhesive. To reduce thickness of material, the blueboard was split and interior corrugation removed so only the paper remained to be adhered (figure 7).
- Padding interior boxes and tray: The interiors of the boxes and tray were padded with closed cell polyethylene foam cut to the shape of the components, adhered in place with hot melt adhesive (figure 8), and upholstered. The box for the shell was upholstered with flashspun high-density polyethylene fabric (i.e. Tyvek®), and the shell pressure-fit with foam attached to the lid (figure 9).
For the box holding the gold hinge, the foam was first upholstered with tarnish preventing fabric (i.e. Pacific Silvercloth®), followed by loose weave cotton fabric, which acted as a barrier to prevent the metal touching the Pacific Silvercloth®. The hinge was lightly pressure-fit with a padded board upholstered with the Silvercloth®/cotton fabric system, which was adhered to the inside of the lid with double-sided tape (figure 10).
For the mounted shell component, which has a base of gilt-silver, the foam was upholstered with the Silvercloth®/cotton fabric system (figures 11 and 12), and given a twill tape pull handle.
- Design and construction of the outer box: Using the same design and construction steps as for the interior boxes, sketch and plan flat schematic for outer box. The height of the required interior dimension was determined by adding together the measurements from the following:
- The height of the mounted shell in the tray
- Safe amount of space above the object and shelf (about 1 ½” in this case)
- Thickness of board for the inner shelf (1/8” in this case)
- Total exterior height of two boxes
The total depth and width was determined to be slightly larger than exterior depth and width of the interior boxes. Dimensions for this box were determined in the same manner as the interior boxes: measuring from the inside out, beginning with the interior bottom and side dimensions required, and adding material thickness.
The bottom and sides of the box were cut, creased and folded first (figure 13a), and temporarily dry assembled together with tape. This action determined where to mark and fold the front flaps that would cross in front of the drop down front (figure 13b, bottom horizontal lines). The places were marked with pencil and creased with bone folder then folded. Next, the side flaps that would attach the back wall to the two side walls was marked and folded (figure 13c, top vertical lines). As with the interior boxes, the blueboard of the flaps was separated, and interior corrugation removed to reduce thickness.
The fold along the edge of the back wall and lid was then folded. The lid dimensions were measured last (figure 13c, green lines). These dimensions can be checked against the final dimensions of the dry assembled box before cutting and folding.
- Adding the shelf: Measure and cut a piece of blueboard to the depth and width needed with tabs on three sides. These tabs are inserted into corresponding slots cut into the sides of the box at the designed height (figure 14).
You will need to determine how many tabs, their size, and spacing that will provide sufficient stability for your needs. For this object the author chose to have three tabs on each of the three sides of the shelf, equally spaced, about 1 ½” long by ¾” wide. Slots for these tabs were marked and cut into the sides of the box, which measured 1/8” high by ¾” wide. Depending on the length of the side flaps, a slot will also need to be cut into each flap that will adhere the back wall to the sides (figure 14, red arrow).
- Adding rare earth magnets for closures to interior and outer boxes: While the outer box was still flat and unassembled, the rare earth magnets were added to close the front flaps of the box and to close the lids of the two interior boxes. The magnet was outlined in pencil, and the top paper of the corrugated board was cut away with a scalpel and removed. The magnet was pushed into the space, compressing the interior corrugation. Blueboard paper was then glued over top of magnet to seal in place. At this time foam padding was added as necessary to custom fit the tray in the box. At this point the box was ready for the final assembly (figure 15).
- Final assembly of the box: The box was assembled carefully by inserting the shelf in place and gluing the paper flaps to the right and left sides (figure 16). The shelf was secured in place by splitting the board of the tabs, removing the corrugation, and adhering the top and bottom paper to the sides of the box (figure 17). Paper was then glued over the tabs to tidy the appearance. The clamshell lid was assembled last around the bottom of the box to ensure an accurate fit.
- Using a clear plastic sheet, such as Mylar, a template was sketched for the interior foam support for the mounted shell (figure 18). Foam was cut and upholstered with Tyvek, then glued in place inside the box with hot melt adhesive (figure 19, red arrow). Corrugated boards were cut for the interior space around the mounted shell, then upholstered in Pacific Silvercloth® and adhered in place with double-sided tape (figure 19, green arrows). Polyethylene foam was adhered on the inside of the drop down lid in line with the edge of the shell, to gently secure the component in place.
- As the final step, the box was labeled as necessary (accession number, image of object and components) (figure 20).
- It is highly recommended that, unless you routinely make housings, practice first by constructing a small box. This will help refine technique and design, determine the best construction, and calculate additional measurements to account for thickness of the materials chosen.
- As mentioned before, measure and construct from the inside out. Triple and quadruple checking measurements is a big time-saver.
- Where possible, add necessary materials (magnets, ties, etc.) while the box is flat, which is easier to do than when the box is assembled.
This housing design was generally adapted from numerous designs already widely utilized for archival storage, but was particularly inspired by a housing made for the Winterthur Museum Archives by Winterthur/University of Delaware Program in Art Conservation graduate student Josh Summer (Class of 2017). Thank you, Josh! Thanks are also extended to William Donnelly, Conservation Technician at Winterthur Museum, whose extensive experience constructing housings provided invaluable guidance for this project.