Thursday, May 11, 2017

Antique Plaster Alginate Knife Restoration


Last year, I had the good fortune to receive the accumulated tools and materials of an acclaimed figurative sculptor who worked professionally in the modelling and fine ceramics and porcelain industry for many years. Among his vast collection of clay tools, rasps, chisels, and assorted modelling implements, I discovered a very interesting double-bladed knife tool. The steel was badly rusted, the bronze handle was covered in a thick layer of crusted patina, and the paper micarta-style handle was warped and swelled due to age. The only markings on the tool to be found were on the blade: "Adam Kalb, 162 Grand St. N.Y.". And so the research began.

Detail of Knife Inscription and Corrosion

After a good deal of research, the only references to an Adam Kalb at 162 Grand Street in New York come from "The Edison Monthly and Electrical Directory" published in July of 1919 by The New York Edison Company and the "Engineering Directory" published in 1921 by The Crawford Publishing Co. in Chicago. Both of these publications are directories of industrial suppliers, tool-makers, and distributors for the various industries and trades of the day. The exact listing reads as follows:

"Adam Kalb, 162 Grand st., New York, N. Y.  Mill, machinists', engineers', electrical and platers' and polishers' supplies. Buyer, Adam Kalb."

Upon further research, I believe the tool to be a plaster alginate knife from the dental and mold-making industry. The knife blade end is used for carving plaster mold pieces and cutting open alginate molds, while the blunt end has a slight bevel that allows it to be used as a prying tool to oped up mold pieces and safely remove patterns and models from the mold without damaging the piece or the knife blade. 
An example of a modern plaster alginate knife from the dental industry.

With the history and context of the knife firmly established and it's use and function established, it was time to restore and refinish the tool to brig back it's luster and beauty, not to mention adding a highly useful implement to my studio tool collection. The long 1-piece steel blade was easily removed from the handle by taking out the rusted set-screws, which allowed me to refinish the blade lightly and redefine and sharpen the cutting and prying edges. Next the handle was sanded down to remove the corrosion, clean up the paper and resin phenolic handle material, and re-polish the entire piece. The blade was re-installed in the handle, and the restoration was complete Here is the result:

Plaster Alginate Knife
Attributed to Adam Kalb, New York - Supplier
Circa 1920's