General Cycling Discussion - Freon vs. Padlock

I've seen several postings here recently stating that a thief could easily shatter the cylinder of any lock using a can of freon. I go to wondering if this is true or just an urban legend. It just happens that I had an old Masterlock No. 1 padlock (the ubiquitous 'standard' laminarted steel lock) and a spare can of R134a coolant laying around so I decided to conduct an experiment for the benefit of the bikeforums readership.

Although R134a is the standard coolant used in automobiles today. It costs a couple bucks per 12 oz can at walmart and is probably the coolant most easily accessible by a thief. Although the old R12 is still available from ebay, it costs approximately $20 per can and is unlikely to be used by a thief for stealing a bike. R134a does not cool as well as R12 in an air conditioner so I would not expect it to freeze a lock quite as well as R12. nonetheless, that's what is available and will be referred to as freon for this discussion.

The idea behind breaking a lock with freon is to direct a stream of liquid freon into the keyhoe of the lock. The theory is that the evaporating freon will rapidly cool the cylinder so cold that the metal becomes brittle. A hard blow with a hammer will cause the cylinder to shatter and allow the shackle to release.

Before anyone attempts to duplicate this experiment, I should remind them to be very cautious when handling any freon-like product. Freon gets extremely cold when it changes from liquid to gas and the vapor can freeze you skin and cause frostbite. Frostbite is serious and can result in amputations, blindness, and surely other nasty conditions. You must wear proper safety equipement and know what you are doing. This doesn't imply that I knew what I was doing, so don't use my description as an example of the proper way to handle this stuff.

What I did was clamp the shackle of the lock in a pair of vice grips which I held using a cloth lined rubber glove. I connected a standard automobile recharge hose to the can of freon. Holding the lock with the keyhole straight up, I opened the valve on the can and held the can upside down so the liquid freon would flow through the hose. I held the end of the hose against the lock cylinder and allowed the entire can to drain out onto the lock.

While the can was draining, I was able to observe liquid running on the lock and into the cylinder. I could also see frost form on the outer surface of the lock.

When the can was empty, I quickly took a hammer and delivered several hard blows to the keyway area of the lock attempting to shatter the cylinder.

The results.

After repeated blows, including some with the lock held against the driveway, there was no evidence of any shattering or damage of any kind to the cylinder of the lock. The outside of the lock did exhibit some minor damage. The plastic 'bumper' arond the base of the lock broke off after several blows. One of the steel laminations comprising the body showed a slight outward bowing, and the rivets on the bottom of the lock were flattened by the impacts of the hammer.

The lock did not open. I attempted to turn the cylinder with a screwdriver without success.

Conclusion. The use of freon to defeat a lock is not a viable technique. My test was against a single lock. Other locks may or may not be susceptible to this attack. However, the lock I used was a low end lock and would likely be most susceptible to attack.

I recommend thieves continue to invest your money in bolt cutters and car jacks.

R-134a is a Freon replacement. I don't think it gets as cold as Freon does. A special license is required to buy Freon, and releasing it into the environment is bad mojo. I know at one time you could report someone and collect the $10,000 fine they ended up paying. I don't know that the difference is enough that your experiment in invalid, it may very well be, but 134a isn't quite the same as Freon.

Yes, you are correct, as I had stated in the original post R134a is different stuff than freon. However, few thieves surely would be willing to fork out $20 a can for something that might not work. If the supposed freon attack were so foolproof, I would have expected R134a to also work. Since it didn't, I would not be concerned about this form of attack. This was the whole point of the experiment.

I suspect that the claim that freon could break a lock probably stems from the possible use of liquid nitrogen to freeze a lock to the point that it becomes brittle. Not having access to liquid nitrogen I could not try that on the lock to verify whether it would work. However, like R12, I would not expect thieves to have ready access to liquid nitrogen.

BTW, even though you supposedly need a license to buy R12, it is available in the small cans on ebay. You just need to sign a form that you plan to resell it.

Yeah, I would think that liquid nitrogen might be an entirely different matter, and the average thief may not know what's what...which is a scary thought in itself.

Yeah, I would think that liquid nitrogen might be an entirely different matter, and the average thief may not know what's what...which is a scary thought in itself.

I worked in a lab with dry ice (-110F) and liquid nitrogen (-320F). I froze my specialized bike computer with dry ice when I was bored one day, after it warmed up it kept working, I still use it now. I froze a small pad lock with liquid nitrogen and dropped it onto a hard floor, nothing happened.

I froze a small pad lock with liquid nitrogen and dropped it onto a hard floor, nothing happened.
I guess this only happens on TV... :p

I had always heard about using liquid nitrogen, not freon, to crack locks. I think the medical profession uses liquid nitrogen to do thinks like wart removal... :eek:

I've got some NOS R12 around from the bad old days, but at $20 a can, I'm not running any tests. :D

Anyway, why bother when a BIC pen is way cheaper and safer? :mad:

not again with the super cold stuff............................................

I guess this only happens on TV... :p

I had always heard about using liquid nitrogen, not freon, to crack locks. I think the medical profession uses liquid nitrogen to do thinks like wart removal... :eek:

I've got some NOS R12 around from the bad old days, but at $20 a can, I'm not running any tests. :D

Anyway, why bother when a BIC pen is way cheaper and safer? :mad:

It might've cracked if I hit it with a hammer but I didn't have one. Where the curve is useful is in knowing if a material, say for a crumple zone in a car, would exhibit ductile or brittle behavior at a certain temperature. As far as lock picking is concerned, there are better ways. Such as installing loose poles in the ground and having people lock their bikes to them then lifting the pole and walking away.

not again with the super cold stuff............................................

Well, super hot would do too. You can buy one of those 5400 degree NOS torches and vaporize the lock cylinder.

Maybe you need some liquid helium to defeat it. That however would be big bucks and very hard to transport. Liquid Nitogren on the other hand is not really that hard to get and it is actually cheaper then soda, well it was a couple of years ago when i found out the price.

When the can was empty, I quickly took a hammer and delivered several hard blows to the keyway area of the lock attempting to shatter the cylinder.

.

What kind of hammer did you use?
I was under the impression this involved using a sledgehammer.

Stacy

I actually used the back end of a heavy hatchet, which was heavier than a standard claw hammer. I would have used a sledge hammer, but as I could not see how a thief could effectively wield a sledge against the lock unless it could be braced against an immovable object. Hitting it with a sledge would also likely deform the case of the lock if it did not shatter and make it even more difficult to open even if the cylinder did shatter. A sledge would also be difficult to direct at the cylinder itself which was the essence of the test.

I believe that a sledgehammer would ultimately defeat the lock give enough good blows regardless of how cold the lock was. My impression was that the r134a (or freon) would get the lock so cold that it would be brittle and should not take extreme force to break. In my experiment, the bottom steel lamination did not even crack, let alone shatter, even though it received the most contact with the coolant and was struck directly with the hammer.

I'm not sure, and I'm not about to buy a lock and some freon (or whatever), and try it, but wouldnt you have to hit the very middle of the lock, the area where the key went in?
Or did you do that, and I just read it wrong?

EDIT: Wouldn't the claw nail remover part of the hammer be better?

I repeatedly hit the keyway of the lock with the hammer. BTW, the claw part of a hammer is not suitable for striking objects with any force. The curvature is wrong and the thin material is liable to break. I used the butt end of a hatchet (it's heavier than a regular hammer) for maximum energy trasfer to the lock. I did consider using a punch or small chisel to strike directly at the cylinder itself, but decided that thieves would not likely be so precise in their actions and it would generally take more than one person to hold the lock, punch and hammer to be effective.

I subsequently did some googling on the subject and the only references I can find that are even close to definitive on this subject is that apparently some car anti-theft devices (The Club) were made with an inferior lock housing which was susceptible to a freon attack. There was also a claim by someone that early models of U-locks were overhardened to the point that they were too brittle and were susceptible.

It may be that this is a good reason for case hardening locks as opposed to through hardening. A case hardened lock would have more resilient metal at its core to resist shattering and a very hard outside to resist cutting. It's kind of like how a samauri sword was tempered or how your teeth are comprised.

....car anti-theft devices (The Club) were made with an inferior lock housing which was susceptible to a freon attack.
Speaking of "The Club", don't they use a similar tubular cyclinder locking mechanism to the Krypto locks (I never used one so I don't know the answer...)?

Speaking of "The Club", don't they use a similar tubular cyclinder locking mechanism to the Krypto locks (I never used one so I don't know the answer...)?


Yes, my co-worker opened his the Bic Pen.