Posts Tagged ‘foil impressioning’

Advanced foil impressioning

Monday, February 1st, 2010

In 2002 I already demonstrated the theory behind the ‘foil impressioning‘ method at the H2K2 conference in New York. The foil impressioning method is nice because it will open quite a number of high security locks and requires relatively little skill to do so. The only thing you need to have is a key cut to the deepest position (preferably a little deeper) and some adhesive aluminum tape that is used in the automotive and heating industry. You apply the adhesive tape over the holes of the key, trim the edges a bit and insert it into the lock. All you need to do now is put some turning pressure on the key and make small ‘up and down’ movements. The pins that are not in the correct position will bind and become stuck in the lock. These pins will push the tape in a little when the key is pushed upwards, and in the next round of ‘turning and rocking the key up and down’ these binding pins will keep pushing in the tape deeper and deeper until shear line is reached. The interesting thing is that once a pin reaches the ‘shear line’ (opening position), it is no longer stuck and will not push in the tape deeper. The key will fit itself …

It is a great technique that is around for quite some time. In my collection of picktools I have some impressioning kits made for the locksmith market in 1995 and 1996. These kits use either foil or candle wax to keep the pins in place. If you take a close look on this key for example, you can see they milled a small fraction of the thickness of the key to make room for the foil. The key including the foil will push all pins to the highest position (or so we hope).

This brings us to the two disadvantages with this method. First of all, if there is a high cut and a deep cut next to each other, the foil is not flexible enough to cope with the difference. In this case you must pierce the tape if the lock does not open in a couple of minutes to allow the deep pin to sink deeper into the foil. And if the pin in the lock is short (a low cut in the key), there is a chance the pin will start to bind because it is not exactly on ‘shear line’. And once this short pin starts pushing the foil in, you lost (as it will sink in deeper and deeper and you will never open the lock). One other disadvantage is that if the profile of the key is not fully flat (meaning if has a serious profile) the tape can not be applied correctly. If you try to put tape over (for instance) this profile, the edges of the profile of the lock will tear the tape when entering the lock. But that latest problem has been solved now by a Chinese tool manufacturer!

Before and after a round of self impressioning

Just brand new on the market is a kit that uses a clever technique to also open dimple locks that have a serious profile (and are not one solid square piece of metal). The kit was brought to my attention when visiting Israel with Jord Knaap and Han Fey last week. A local locksmith called Raf (well known from the UK bumpkey forum) invited us to his shop and proudly showed me this tool and technique. The way the tool works is that you first take some aluminum foil and make a ‘U shaped’ form (using the special tool to do so) and make small incisions on pre-determined positions. Next thing you do is put the foil over a special blank that already has the profile of your target lock. The clever thing about this tool is that the ‘U shaped foil tube’ is wrapped around some sort of needle, and the foil can not be pushed in when entering the lock! Once the key is inserted, the needle is taken out from the back of the tool, and the pins are now resting on the foil. Because of the cuts in the foil, each pin will stand on it’s own ‘island’ of foil, and when it is pushed in will not disturb the neighboring pin! I have played around with it a little, and the design is really very clever and works fast and reliable!

There is something to complain though. The tool itself is made from ehrm …. not the best quality steel and will break after several tries. Nevertheless it is a great tool for it’s value, and I am sure this new method of ‘foil tubing’ can be applied to many more locks too ….

Thank you Raf (and friends) for the good time, and of course for your excellent video demonstration of this great new tool!