Vacuum fuming is a relatively new cyanoacrylate fuming process. Traditional superglue fuming methods involve placing evidence in a fuming tank or chamber and exposed to cyanoacrylate fumes in a normal atmospheric environment. The fumes are allowed to flow “naturally” from the source of the superglue. One concern of using the traditional method is that items placed closer to the source of the cyanoacrylate fumes run the risk of over-development while items on the other side of a larger tank may not get as much exposure to the fumes. Large items like plastic garbage bags have to be fully outstretched so all surfaces are exposed to the fumes. The vacuum method addresses this concern. Vacuum fuming tank with pump The apparatus design is relatively straightforward. The tank consists of a metal tube which is sealed on one end and has a removable thick plastic lid for the other end. A vacuum pump is attached to the tank and there is a pressure gauge mounted on the outside of the tube tank. Items to be fumed are placed inside the fuming tank but it isn’t necessary to open up plastic bags or keep items separated to get proper exposure to the cyanoacrylate fumes. That is not to say you want to force pack items in there like a washing machine but you don’t have to be as concerned about evidence spacing. After the items are placed in the tank the cyanoacrylate pack or dish is placed in the tank or taped to the lid. Once the lid is on the pump is turned on and the air is evacuated from the chamber. Items can typically be removed for examination after about 20 minutes although there is no danger of over-fuming that can occur with traditional fuming chambers. One risk is that you can’t process pressurized items like aerosol cans, unopened soft drinks/beer, or other similar products unless you want a real mess and possible explosion. Of course, that might be something you could consider having a crime lab intern do on accident thereby ruining crucial evidence in the case. Fingerprint on knife developed with cyanoacrylate fuming Surprisingly, not many crime labs have these types of fuming chambers. Many rely on the more common fuming tanks for a variety of reasons. Even if they do have vacuum tanks they may not be used very often. We do have one in our Flint lab. GCCW
Posted on: Mon, 07 Jul 2014 03:14:47 +0000
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