You've probably seen or read about this before in books or on TV; the grizzled old police detective steps into the scene of the crime and sees the lighter/handgun/baseball bat left behind by the criminal. He takes the evidence home, and with the power of super glue extracts a perfect print and catches the thief. But how does it work? Super glue is made of cyanoacrylate, a substance that, when heated to a vapour, reacts with the oily residue left behind by the pores of the finger to create a fingerprint on a piece of evidence, such as a gun. if the evidence is put in a heated airtight container with high humidity (this is where the dish of hot water comes in) along with super glue the super glue will boil away into the immediate atmosphere and will eventually settle on the residue left behind by the finger. The reaction gives the residue a whitish appearance, making the fingerprint easy to see.
Step 1: What You Need:
- Duct tape or masking tape
- Small container (to hold hot water)
- Super glue
- A heat source, such as an incandescent light bulb (I used the base of a lava lamp)
- A piece of "evidence" with a fingerprint on it (smooth, hard materials like plastic, metal and glass work best)
Step 2: Preparation
- Cut a small hole in the side of the box to accommodate the power cord of your heat source.
- Place the tinfoil dish as close to the heat source as possible, and place the small container opposite it.
- Put your evidence between the tinfoil dish and small container.
Step 3: Developing the Print
- Boil some water and fill your small container with it.
- Squeeze a nickel-sided drop of super glue into the tinfoil dish, then close the box.
- Tape around the lid to make the box airtight. The faster you do this the better.
- Check on the evidence after 30-45 minutes. If nothing has happened, add a little more super glue and wait another 30 minutes.