Click to search the Andrew Heiskell Braille and Talking Book Library Skip Navigation


What a Tool: The Hot Knife


Welcome to What a Tool, the inaugural post in a continuing series that will highlight some of the tools and equipment used in the Goldsmith Conservation Laboratory to perform conservation treatment on the NYPL's varied and unique collections. Episode one: the Hot Knife.

One of our many responsibilities in the conservation lab is to create custom-made housings (which are essentially protective containers) for some of the NYPL's most unusual and fragile objects. The Manuscripts and Archives Division recently acquired the Timothy Leary Archive (you can read about some of the greatest hits from the Leary papers in Archivist Jennifer Ulrich's recent blog post). Conservators treated some of the items in the collection, and that included making a special housing to protect a plaster mask made from a mold of Timothy Leary's face.

The tools used for conservation treatment are varied and interesting. Sometimes they are created specifically for the conservation profession, but often they are made for other more commonly-known industries or activities and are adapted for use by conservators. The Hot Knife is an electric tool with a heated blade that can be used to cut and shape other materials. It's most often used for hobby or craft work and has applications for creating displays, theater sets, or miniatures like train sets. In the conservation lab, the heated element can be used to cut through foam as easy as cutting butter with, well, a hot knife.

The challenge in creating a housing for the Leary mask was to make something that would enable access to the mask (notice the front side of the box that drops down), holding it firmly and securely in place while still protecting the fragile plaster. A box made of acid-free board was expertly constructed by the Preservation Division's Collections Care department, using its Kasemake box-making machine. Soft foam was contoured to fit exactly around the perimeter of the mask, and the Hot Knife was used to cut and shape a protrusion of polyethylene foam to fit precisely into a recessed area on the back of the mask. Combined with a layer of soft foam under the mask to cushion it, the housing holds the mask securely in place and provides excellent protection.

The Timothy Leary papers can be accessed though the NYPL Archives Portal ( Check back here for future episodes of What a Tool.


Patron-generated content represents the views and interpretations of the patron, not necessarily those of The New York Public Library. For more information see NYPL's Website Terms and Conditions.

Post new comment