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NCJ Number: 64911 Find in a Library
Title: USE OF MOLDED PLASTICS FOR PERMANENT PROTECTION PRESERVATION OF OBJECTS FOR ORGANIC MEDICAL STUDY
Journal: KRIMINALISTIK UND FORENSISCHE WISSENSCHAFTEN  Issue:25  Dated:(1976)  Pages:71-76
Author(s): H VONJORDAN; H FRITZ; D WINTER
Corporate Author: Johannes-Dieckmann-Str 10
Veb Deutscher Verlag Der
Wissenschaften
West Germany (Former)
Date Published: 1976
Page Count: 6
Format: Article
Language: German
Country: West Germany (Former)
Annotation: THE ADVANTAGES OF USING MOLDED PLASTICS FOR PERMANENT PRESERVATION OF EVIDENCE ARE OUTLINED.
Abstract: MOLDED PLASTIC PRESERVATION IS PREFERABLE TO DESCRIPTIONS, SKETCHES, AND PHOTOGRAPHS BECAUSE PLASTICS PERMIT EASY DUPLICATION OF EVIDENCE AND PRESERVATION FOR AS LONG AS NEEDED IN AN INVESTIGATION. MATERIALS USED MUST HAVE LOW SURFACE TENSION SO THAT THEY FLOW EASILY, OPTIMAL DUPLICATION OF DETAILS SO THAT MISCROSCOPIC COMPARISONS ARE POSSIBLE, PERMANENT RETENTION OF SHAPE, REMOVABILITY SO THAT NO SEPARATION MEDIUM IS NECESSARY, AND EASY PREPARATION TO FACILITATE USE AT THE CRIME SCENCE. IN THE PAST PLASTER OF PARIS AND THE HYDROCOLLOID NEGOCOLL WERE USED; MORE RECENTLY ALGINATES SUCH AS VEREX AND ZELEX (USED FOR MAKING DENTAL CASTS) HAVE BEEN EMPLOYED. HOWEVER, SYNTHETIC LATEXES SUCH AS LATEX SS AND CHEMILAT D1102 OR D1500 ARE NOW USED AS THEY CAN COAT A WHOLE OBJECT WITH A TRANSPARENT FILM WHICH SEPARATES EASILY IN 5 TO 10 MINUTES, AND AS THEY SWELL IN SOLVENTS SUCH AS BENZINE TO PRODUCE ENLARGEMENTS. COLD-CURING SILICON RUBBER PASTES SUCH AS SILCOFLEX ARE USED FOR LARGER OBJECTS TO AVOID SHRINKING DISTORTIONS WHEN A THICKNESS OF MORE THAN 1 MM IS NEEDED; THE PLASTIC IS MIXED WITH HARDENER ACCORDING TO THE SIZE OF THE OBJECT. HARDENING TIME VARIES WITH THE AMOUNT OF HARDENER, BUT REMAINS FAIRLY CONSTANT AT BETWEEN MINUS 15 DEGREES AND PLUS 50 DEGREES C; THE COLD-CURING FEATURE MAKES IT POSSIBLE TO USE THE SUBSTANCE AT ANY LOCATION. ALTHOUGH SHAPE AND VOLUME OF THE HARDENED SUBSTANCE REMAIN CONSTANT, CASTS OF VERY LARGE OBJECTS SHOULD BE REINFORCED WITH PLASTER OF PARIS. SILCOFLEX NEGATIVES CAN BE SILVER COATED OR TAKEN DIRECTLY FOR POSITIVE CASTS WITH ANY OF THE COMMON POSITIVE MATERIALS. INSTRUMENTS CAN BE EASILY WIPED OFF AFTER USE. A SHORT BIBLIOGRAPHY IS SUPPLIED. --IN GERMAN. (KMD)
Index Term(s): Casting techniques; Evidence preservation; Trace evidence
To cite this abstract, use the following link:
http://www.ncjrs.gov/App/publications/abstract.aspx?ID=64911

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