How Does Superglue Fuming Work?

Modern fuming chamber with humidifier on right side

Superglue fuming is a chemical process to reveal and “fix” latent fingerprints on non-porous items such as bottles, firearms, knives, etc.  The process work by heating liquid cyanoacrylate (i.e. superglue) which releases gaseous vapors that adhere to the oily residue of the fingerprint. In the laboratory this is done in a fuming chamber. When I first began my career this amounted to a fish tank.  It was simple, crude, and messy. While I suppose some smaller agencies may still use these tanks the vast majority of modern labs use a chamber designed specifically for this function. These chambers control humidity and heat activation. Humidity is an important factor to control because the moisture in the chamber helps to re-hydrate the fingerprint residue. They also evacuate the dangerous fumes so the examiner isn’t exposed to them when they open the chamber up. With the old tanks we’d throw open the lid under a fume hood and run so as not to be exposed to the dangerous vapors.

Superglue developed fingerprint

Examiners can also use a fuming wand to expose items to the cyanoacrylate vapors. They are basically butane fueled lighters that heat small brass capsules of cyanoacrylate infused packing. These wands are typically used in the field on larger items that can not be moved or placed into the fuming chamber. Care must be taken not to inhale the vapors and a safety mask is recommended for use. Also, since the wand can get very hot you don’t want to lay it on anything flammable.

CSI using a fuming wand in the field

Upon development the fingerprint ridges will appear a white chalky color. In this state they may be photographed, treated with fingerprint powders and lifted, or treated with liquid dye staining reagents and photographed with an alternate light source. The impressions are much more durable than in their untreated state which means an examiner may have an opportunity to make a second or third tape lift if need be. All in all, superglue fuming is one of the most common techniques in the laboratory for processing non-porous items for fingerprints.

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About forensics4fiction

Hi there. Thank you for visiting my BLOG for crime writers. I hope you will find it interesting. I would love to hear your questions and thoughts regarding forensics and criminal investigations. I hope that the information here will help answer your questions or ignite your imagination. I am a retired senior criminalist with 15 years of forensic experience. I have served as the president of the Association for Crime Scene Reconstruction, Rocky Mountain Association of Bloodstain Pattern Analysts, and the Rocky Mountain Division of the International Association for Identification. I am triple board certified in forensic related fields and one of only 40 board-certified bloodstain pattern analysts and 80 board-certified footwear examiners worldwide In addition to writing over 60 scientific papers, I have worked as the editor of the Journal of the Association for Crime Scene Reconstruction, been interviewed by and consulted for television, books, magazines, and newspaper articles including documentaries on the Discovery Channel and National Geographic.

Posted on May 22, 2011, in The Crime Laboratory, The Crime Scene and tagged , , , , , , , , , , , , , , . Bookmark the permalink. 9 Comments.

  1. I am not a chemist and need some guidance with an idea I have.

    I can see how super glue works in fingerprint detection.

    I have an application where glass is coated with atomized polyethylene wax emulsion which leaves a wax “dot matrix” on the glass surface. After application the wax is invisible on the glass surface. The dot matrix distribution is dependent on the density of the atomized application.

    Can I use the super glue vapor method to bring out the polyethylene dot matrix “fingerprint” on the glass surface. To achieve visibility I need the vapor to either bond to the polyethylene wax or the glass. Can super glue vapor achieve either of these requirements and if not, do you have any suggestions

  2. Honestly, without knowing more about the wax I can’t say but I do know that this method can develop “waxy” deposits on glass. You may need to expose the glass to some humidity before you begin and just make sure you do it in a well ventilated area with an appropriate respirator.

  3. I am studying Criminal Investigations and this has helped me out with some of the questions that I had regarding the super glue technique. Thanks

  4. That makes me very happy Patricia. Thanks for visiting!

  5. Are there other benifits from superglue, such as getting DNA from it? using the pcr technique there must be loads of advantages..i need to know for an essay}:

  6. If you mean getting DNA from the developed prints it is theoretically possible but usually not needed. DNA swabbing occurs before fingerprint processing at both scenes and on items. Analysts are trained to evaluate which items or locations are better suited for DNA sampling before they do fingerprint processing. For example, if you recovered a beer bottle from a scene you would swab the opening (mouth) for DNA then process the bottle itself for FPs. If you recovered a gun you could swab areas not suitable for prints like the trigger or checkered parts of the grip, etc and then process it for prints. The same is true of scenes. A vehicle steering wheel is not a great surface to recover FPs but can be swabbed for DNA. Does that make sense? Obviously, if you only have a single item you’d have to evaluate a number of factors such as how the item is used, material construction, surface area, environmental conditions, etc. before deciding which of the two techniques is better suited for getting the information you need. The problem with SGF is that it binds to the residue and creates a protective coating which may interfere with ability to extract DNA (fuming time is obviously relevant). Hope that helps.

  7. Much appreciated! (fast reply!)

    furthermore i wanted to know how many advantages there are of superglue fuming method, From this technique is it possible to obtain several lifts?from research i have found out that you can add dyes in order to achive a higher quality print, so it’s more visible, such as fluorencent dyes, so under UV light it would be visual, more detail of the print!, i just want to know how many other advantages from superglue method can you get, surely there are more!

  8. Hi I’m a fingerprint specialist here in Brazil. I’m testing a superglue fuming chamber I’ve made. Is there any difference in quality using Loctite’s superglue X generic cyanoacrilate in the chamber ? My first impression was that generic cheap cyanoacrilate ester vaporizes quicklier and develops fingerprints that are not tough enough to last forever . Am I right?

  9. To be honest I’ve never tested it. I would recommend using a superglue from one of the big forensic companies.

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