NCJ Number
223663
Journal
Journal of Forensic Identification Volume: 58 Issue: 4 Dated: July/August 2008 Pages: 485-500
Date Published
July 2008
Length
16 pages
Annotation
This article reports on validation studies for a snow impression casting medium, i.e., sulfur cement, which is a silica-filled, modified sulfur mixture with physical properties suitable that make it an excellent replacement for pure sulfur as a hot-melt casting compound for snow impression evidence.
Abstract
The study found that sulfur cement exhibits physical properties that make it an excellent replacement for pure sulfur as a casting material for snow impression evidence. It has a much higher bending strength than pure sulfur and has a compressive strength greater than pure sulfur and comparable to dental stone. Although pure sulfur has been well-documented as a suitable material for casting snow impressions and has the advantage of speed and quality results, it requires additional equipment not usually carried in an evidence collection kit: a stove, melting pot, stirring utensil, and a respirator. Pure sulfur also tends to be brittle, which can cause difficulties for both the crime-scene officer and the laboratory examiner. Transporting pure sulfur also presents logistical problems, since it is considered a hazardous substance and cannot be mailed through the U.S. postal system. Sulfur cement is a modified sulfur mixture with added silica. The materials used in the casting are listed, and the casting method is described. 1 table, 9 references and 9 figures