Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Raising a destroyed (ground down) Hull I. D. # on an Aluminum boat

Q. I'm a firearms examiner at the [surname deleted for privacy by Editor] Police Dept. Crime Lab. I'm working on a research project involving serial number restoration on titanium and scandium alloy firearms. In a nutshell, serial number restoration uses chemical etchants (acids) to enhance obliterated characters from metals where plastic deformation has occurred in the crystalline structure of the metal.

What acids can SAFELY be used (i.e., Not HF) on Titanium? Any thoughts on what to use on Scandium?

Thanks in advance...

Jill E [surname deleted for privacy by Editor]
Crime Lab - Florida

Q. I am a Marine Deputy Sheriff and we are trying to raise the HIN on an aluminum boat that has been purposely ground down so as to try to disguise the proper ownership of this vessel. I recently attended a training session that showed how to use a chemical soup [ ... ] but the instructor wasn't quite clear on this.

Nicholas J [surname deleted for privacy by Editor]
- Coos Bay, Oregon

March 30, 2009

Hi, Jill; hi, Nicholas. There are many books and blogs describing such methods:

- "Crime Scene Training" at www.csitechblog.com/2011/07/how-crime-labs-restore-obliterated-serial-numbers.html
- "Idaho State Police Firearm/Toolmark Procedure Manual, Section 7: Serial Number Restoration" at www.isp.idaho.gov/forensics/documents/currentAMs/Firearms/Section%207%20serial%20number%20restoration%20rev%200.pdf
- "Serial Number" at what-when-how.com/forensic-sciences/serial-number/
- "Handbook of Methods for the Restoration of Obliterated Serial Numbers" by Richard S. Treptow at books.google.com.br/books/about/Handbook_of_Methods_for_the_Restoration.html?hl=pt-BR&id=0_HdHAAACAAJ

... but we deleted your partial explanations so that we don't make it easy for people who have ground off serial numbers to check the reliability of their work if you described an unpublished method :-)

If any reader can fill you in on these details that weren't clear, we will be happy to direct their response to you or put them in contact with you.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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