Serial Number Restoration

1. Serial Number Restoration

2. Serial Number – A unique number typically applied to an object by a manufacturer Serial Number Restoration – The practice of restoring an obliterated serial number by using scientific methods

3. Types of Serial Numbering Application Methods Serial numbers can be applied in a variety of methods. Each method has unique characteristics which enable them to be differentiated from each other.

4. Dot Matrix • Dot matrix engraved serial numbers are fairly shallow and are made by a succession of dots

5. Laser Engraving • Serial numbers engraved with a laser are shallow and have a “burned” appearance.

6. Stamped Serial Numbers • Stamped serial numbers are made by using a stamp with a positive impression of a number and applying sufficient pressure to impart a negative impression of the stamp on the object

7. Stamped Serial Numbers

8. Stamped Serial Numbers - Theory • The compressed area at the base of the stamping is strained below the surface of the stamp mark

9. Obliteration • When serial numbers are obliterated, they are generally ground down beyond the lowest point of the original stamping. • This results in the visible portion of the serial number being removed. • By removing the serial number, criminals hope that the object can not be identified as having been stolen.

10. Obliteration • The serial number is no longer visible due to the removal of the top layer of the metal. • The area below the obliterated layer is affected by the stamping process and is the reason serial number restoration is possible.

11. Visualizing Restorations • Serial numbers appear when they are acid etched due to specular reflection. • Specular reflection – light reflecting off a smooth surface • Diffuse reflection – light reflection off rough surfaces Specular Reflection Diffuse reflection Rough Surface Smooth Surface

12. Serial Number Restoration • An obliterated serial number typically has a surface that has been scratched so that the number is no longer recognizable

13. Serial Number Restoration • The first step in the process of restoring the serial number is to polish the surface by using sand paper in progressively finer grits. • Polishing the surface will help in visualizing the serial number.

14. Serial Number Restoration • Acid Etching – The acid reacts with the metal and produces hydrogen gas bubbles

15. Serial Number Restoration • The result of the acid etching is a restored serial number. The dark appearance of the numbers is the result of diffuse reflection.

16. Case Studies • An ATV was suspected of having been stolen from a local dealership. • When police attempted to read the VIN (Vehicle Identification Number) it was observed that it had been obliterated. • The number in question was located on the engine

17. Case Studies • The surface with the obliterated number was located on the top of the engine block

18. Case Studies • This is the area on top of the engine where the VIN number was stamped. • The first step in the restoration process will be to sand it smooth.

19. Case Studies • After the surface was sanded, Acid was applied to the engine block.

20. Case Studies • The Vehicle Identification Number was restored to H310E-06674. Using this information, police were able to verify the ATV was stolen and press charges against the suspect. H 3 1 0 E - 0 6 6 7 4