Acidified Hydrogen peroxide

[ Return to: Main Page || Non-Porous Surfaces || Metal Surfaces || Cartridges ]

Chemical Name:
Acidified Hydrogen peroxide

Surface Used On:
Brass cartridge cases.

Sensitive To:
Repelled by sebaceous components.

Development Color:	Method to Record:	Hazard:	Protective Clothing:	Fume Hood Use:
Gray				Yes

Reagent Characteristics

Development Complete When:

Source of Error:

Incompatibilities:

Precautions:

Storage Container:

Safety:

Recommendations:

Similar Reagents

Sequential Reagents
(Not necessarily in this order.)

Abridged Reagent Sequence

Visual Examination
|
Cyanoacrylate
|
Gun Blueing
|
* Acidified H₂0₂ *
|
Visual Examination

Acidified Hydrogen Peroxide FORMULA:

14.1 ml of 5% household vinegar

20.0 ml of 3% household 
	      Hydrogen peroxide

PROCEDURE OF APPLICATION

1. Light fuming of cartridges
with cyanoacrylate ester. Do not
fume in a superglue chamber.

2. Immerse cartridges in
the reagent. Gently stir and
roll cartridges in the solution.

3. Monitor closely for development.

4. Halt development by
immersing in water bath
for 2 minutes.  Air dry.

NOTES:

Lacquered steel cartridges or
those cartridges with a polymer 
jacket around the casing will resist 
the oxidation/reduction resulting in 
little or no development with this 
formulation.

Ridge Detail Visualized by:

Visible chemical/stain reaction.

Reagent Applicabilities:

Non-Porous surfaces
Post-Cyanoacrylate
Cartridge surfaces

Other Chemical Name(s):

Process Summary:
Acidified Hydrogen peroxide is used to clean lead from bullets, and has been found to remove excess gun blueing from cartridges. This reagent can also be used by itself to reveal friction ridge detail with less chance of over-development as compared to gun blueing. The reagent etches the cartridge's metal surface not protected by sebaceous-containing latent print residue. A gray-colored coating is developed on the regions that have been etched. Cartridges should first be briefly fumed with cyanoacrylate ester, then immersed into the acidified hydrogen peroxide solution. A water bath stops the chemical reaction.

Accepted Deviations:
The hydrogen peroxide solution and the vingear are household products that may be purchased at your local grocery store or pharmacy. The use of cyanoacrylate fuming as a pretreatment may be skipped. A clear lacquer spray can be applied to the cartridge cases to stabilize the development process, and, to enhance the contrast of the developed friction ridge detail.

Supporting Reference Materials:
1. "Use of Acidified Hydrogen Peroxide to Remove Excess Gun Blue from Gun Blue-Treated Cartridge Cases and to Develop Latent Prints on Untreated Cartridge Cases", Cantu, A.A., Leben, D.A., Ramotowski, R., Kopera, J., Simms, J.R., Jor. Forensic Sciences, Vol. 43, No. 2, pp. 294 - 298.
2. "Evaluation of Gun Blueing Solutions and their Ability to Develop Latent Fingerprints on Cartridge Cases", The Chesapeake Examiner, Vol. 8, No. 10, October 1996.
3. "Visualization of Sebaceous Fingerpirnts on Fired Cartridge Cases: A Laboratory Study", Migron, Y.,Hocherman, G., Springer, E., Almog, J., and Mandler, D., J. Forensic Sciences, Vol. 43, No. 3, May 1998, pp. 543-548.

[ Return to: Main Page || Non-Porous Surfaces || Metal Surfaces || Cartridges ]