acid attacks or lock testing

Gary Stephenson

I saw a picture of a tool once for introducing acid into the Chubb 6K174 isolator keylock to dissolve the levers, does anyone have any details of acid attacks or manufacturers testing against this method?
I was told the mixture of brass and steel levers and the drain hole in the bottom of the 174 lock were design features to mitigate this attack.

Cepasaccus

The European safe test is also testing attacks to the lock installed in that safe to be tested. That is why there is a qualified lock list coming with the safe which nobody gets. One attack which they do consider is the melting of the lock (zamak case). For protection there are relockers and bolt extensions made from steel. In their tool list is also acid and alkali with 10 RU/min and a BV of 7 for 1 liter. So they do probably consider this too. Grade III safe has an RU value of 120. When using just 1 liter of acid it means that the safe must not be open in about 11 minutes. My guess is, that in modern locks the zamak case will be destroyed before the levers in which case the relockers and bolt extensions will stop the burglar. But if the bolt stump (zamak) goes first, then the lock is open with a wire (BV 1).

safeman

Gary Stephenson wrote
I saw a picture of a tool once for introducing acid into the Chubb 6K174 isolator keylock to dissolve the levers, does anyone have any details of acid attacks or manufacturers testing against this method?
I was told the mixture of brass and steel levers and the drain hole in the bottom of the 174 lock were design features to mitigate this attack.

Gary, I don’t know of any criminal attacks using acid, well not in this century, only legitimate test work as this old post describes.

From memory it took around 30 very stressful minutes to open. The main difficulty was obtaining a syringe with no brass components to apply the acid.
Incidentally the old Tann 4S 7-lever Guarded Lever lock always had 2 steel levers within the pack.

[unknown]

Cepasaccus

You have made the error with sulfuric acid as being part of aqua regia, which was corrected in a later post. It was then not discussed if the fuming sulfuric acid was also an error. I never have used fuming sulfuric acid. If someone would ask me for what I would try, I would say fuming or non-fuming nitric acid and would try first the non-fuming, concentrated version.

There was in Germany a Proctor model from the 80s, which had an integrated relocker attached to a wire passing through the inside of the cover. I don’t think it was designed with acid attacks in mind. As far as I know it was designed as a countermeasure for milling attacks through the lafette hole. But it might be tripped by acid too.

safeman

Cepasaccus wrote
You have made the error with sulfuric acid as being part of aqua regia, which was corrected in a later post. It was then not discussed if the fuming sulfuric acid was also an error. I never have used fuming sulfuric acid. If someone would ask me for what I would try, I would say fuming or non-fuming nitric acid and would try first the non-fuming, concentrated version.

There was in Germany a Proctor model from the 80s, which had an integrated relocker attached to a wire passing through the inside of the cover. I don’t think it was designed with acid attacks in mind. As far as I know it was designed as a countermeasure for milling attacks through the lafette hole. But it might be tripped by acid too.

Cepasaccus, thank you for your comments. The only reason that I responded to the Banks request was to put the Security Manager’s mind at rest. He was being way over the top but was my best customer. He envisaged an acid attack on a double high line of 30 Stratford Sterling Kromer Novum locked light cash safe which housed much of the Bank’s cash reserves within the main Chatwood strongroom. His thinking was that by applying acid into safe No.1 right through to No.30 by the time the last one had been injected the first one would be open.

The thought that the Lafette could be compromised by these methods seem ludicrous but I’m not in any way qualified in other than basic safe locking. I did however come up against the Lafette when asked to open a Bode Panzer in what had been the German Consulate in Glasgow in 1950. Fortunately a member of the NHS staff now in occupancy realised that a strange little object in her desk drawer might be connected to the safe with no keyholes.

[unknown]

Cepasaccus

Had a look into the catalogue:

“Ausführung K85, Schutz gegen chemische und Bohrangriffe” (Variant K85, protection against chemical and drill attacks)

The patent for this relocker is DE3226444A.

Tom Gordon

Not mentioned here is that corrosion rates are very significantly higher at 60 degrees C- not hotter

Billy B Edwards Jr. CML

In the late 1980’s the US Military included an acid test. To my knowledge Only S&G’s 813B padlock could pass the test. They developed a special chemical coating that stopped the acid attack against the Medeco cylinder utilized in the lock. Coincidentally the coating process turned the color of the brass to an olive drab color. While I have no personal knowledge regarding the subsequent models, I’m sure the test would still contain the acid element.
BBE

Cepasaccus

MIL-DTL-43607J w/ Amendment 1, 29 JULY 2010
PADLOCK, KEY OPERATED, HIGH SECURITY, SHROUDED SHACKLE

3.3.1.1 Dissimilar metals. Dissimilar metals, as defined in MIL-STD-889, shall be coated, plated, or
electrically insulated from one another to minimize or prevent galvanic corrosion.

4.5.1.11 Salt spray (fog) resistance test. The padlock and keys, with keys not inserted in the
cylinder plug, shall be subjected to 96 hours of salt spray (fog) in accordance with ASTM B 117.
After 96 hours, rinse the padlock and keys in tap water, and examine for evidence of deterioration of
any component. Any evidence of deterioration, except for minor corrosion spots that obviously do not
affect the performance of the padlock, shall constitute failure of this test (see 3.5.2.9).

Gary Stephenson

cheers fellas, all very interesting.

Gary Stephenson

found some old photos, not the best quality unfortunately, and a memo.

Gary Stephenson

more examples

Gary Stephenson

chubb lock

Gary Stephenson

The later open case version of the 6K18 lock

Gary Stephenson

Photos aren’t the best quality, but I think this is the plastic bolt (lightweight version) of the 6k18, I don’t know if the use of this bolt was tried to thwart an acid attack or for other reasons.

Cepasaccus

Thanks for sharing these old photos.

According to EN 1134-1 1 liter acid is a base value of 7 and a RU value of 10 per minute of usage. In case of the optimized 10 minutes it is total 107 RU. No idea how they would rate additional equipment to inject the liquid and move the bolt. A grade III safe hast to provide 120 RU. So it would have nearly failed this test or not.