How to Replicate Fingerprints




Introduction: How to Replicate Fingerprints

Some maker friends and I stay in the college's hostel, and getting out of hostel after 9.30 pm is difficult, as you need all sorts of permissions from the administrators. Also, our biometric fingerprint attendance is taken, to ensure that no one is outside without permission.

To liberate ourselves from this pain, we made moulds for faking our fingerprints. Now, the possibilities are many using these moulds, but keep in mind, we are hacking to improve upon the technologies, not misusing it.

Step 1: Materials Required

( x1 5 g each) Sugru

(x1 stick) Hot Glue, and

(x1 Tube) Fevicol adhesive (school glue)

Step 2: Methodology

The first sugru mould on which we press the finger has the negative image/impression of our fingerprint.

We take another mould material and place it over the negative mould. This new mould has the positive impression, which we can use to replicate fingerprints. It's that easy.

Beware security guys, here we come!!

Step 3: Put First Impression on Sugru

First mix sugru well in your hands, so that it becomes soft. Now, make it flat like a disc. Press your finger onto the sugru disc. Make sure that you don't move/shake your hand much while taking impression.

Now, you have created a negative impression on the sugru mould.

Let Sugru cure for one day.

For the sake of this instructable, let's call this the negative (-ve) mould.

Step 4: Make the Positive Impression Mould

Now, you have the sugru negative (-ve) mould. Now which material do you want the mould to be? You have 3 options:

1. We can use fevicol / white adhesive. Use a brush to apply glue over the sugru -ve mould and let it dry. Gently peel it off after drying.

2. Use a glue gun and pour hot glue on a flat surface (you can apply powder to make it easy to remove).

When the glue is still molten, press your sugru -ve mould on it, so that the fingerprint part of the mould is in contact with the hot glue.

3. Use sugru again! Get some more Sugru and press it on the negative mould. Let it cure for one day and remove it to get your final mould.

After letting the mould dry, call it the 'positive mould'.

Step 5: Now, Get Ready for Testing!

Now get your final positive mould and press it on a stamp pad. How does the new fingerprint look? Compare it with your original fingerprint.

Let me know if you were able to cheat any fingerprint readers, you might also try fooling readers using the negative mould !!

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    9 Discussions


    4 years ago

    I use Instamorph (polycaprolactone) for the mold and Oogo (caulk) for the cast. Much cheaper than Sugru!


    5 years ago on Step 5

    ohh...... the happy new year's trick ? hehe....... good one.......


    5 years ago on Introduction

    This is awesome! What of the 3 options for your positive mould would you say worked the best?


    Reply 5 years ago on Introduction

    The fevicol one was good, but Mseal is also nice. The thing with Sugru and Fevicol is that they bend, so the gap between the lines changes depending upon the bend, Abhinav?


    This is like spy stuff.. it would be cool to make something to cover your own fingerprints with someone elses.