Observations from the recent viewing of the TPTV film "Golden Sewers"

Have just enjoyed watching the film “Golden Sewers” on TPTV which I thought was a good example of the typical safe-breaking genre but was taken by two things. The film, based upon a true story in France featured members of a gang breaking into an underground vault with oxygen and propane gas cylinders, the latter clearly marked as being supplied by Calor Gas, unlikely considering that the break-in took place in Nice.

Secondly, the Oxy/Propane torches employed by the characters in the film are used for cutting through steel bars and for the sealing up from the inside the large heavily plated steel door. I wonder just how practical would this arrangement would have been as surely Oxy/Acetylene would have been the more usual combination of gases for this type of work?

Artistic licence

Like all those 1900-1980 period dramas where no-one smokes

I think acetylene was preferred by safe breakers everywhere in the past. Maybe the new generation use propane? Wouldn't think it as hot or as quick as the acetylene. Yes artistic license by movie types who are not engineers.

Nothing new. Remember the Lawrence of Arabia movie with Peter O'Toole made in the 1960s? The ship sailing up the Suez in it had a 1960s motor ship's low funnel (Blue Funnel Line IIRC) and not the tall stacks a coal-fired triple-expansion engined steamer of WW1 vintage.

The only purpose of the fuel gas when cutting is to get the metal cherry red. Once at temperature the cutting process does not need a fuel gas, as the reaction between hot iron and oxygen is exothermic. Once started the cutting process is self-sustaining. So oxy-propane is fine for cutting, and is widely used commercially as propane is cheaper and easier to handle than acetylene.

Andrew

Yes Oxy Acetylene is hotter and would get the cut started but the process is exothermic and once started can be kept going with the fuel gas turned OFF - I've done it many times just because I can ! Propane would be a bit slower but once started will keep going as fast !

The Canerbury tales - the millers tale, set in 14-15th century yet the stubble fields clearly showed that a combine harvester had been use, the straw laid in swaths ! Ah well, Noel.

Correct except the flame produced by a Thermic Lance is hotter than Oxy-Acetylene! The volume of heat produced by a lance is typically higher too unless the Oxy-Acetylene torch is massive.

Oxy-Acetylene 3000 to 3480°C, Thermic Lance 2730 to 4500°C

The lance consists of a steel tube, several feet long and packed with fine steel wire and some flux. Oxygen is fed in one end and the other ignited with a flame hotter than 1600°C : usually Oxy-Acetylene or Oxy-Propane.

The burning steel produces a puddle of molten Iron Oxides hotter than the melting point of steel, which serves to concentrate and promote heat flow into the target whilst directing hot Oxygen into it. Run flat out and Oxygen rich, the flame is well above the boiling point of steel, and the vapour also ignites adding even more energy to the burn.

Although Thermic Lances easily cut Concrete, Steel and pretty much everything else, they're not precision tools! Used to break into a safe or vault, there's a high-risk the contents will be destroyed by the huge amount of heat.

Anyone know what the hottest possible chemical flame temperature is?

I think Hydrogen and Fluorine burn hotter than 4500°C but high temperature facts are hard to come by. Another possibility is Fluorine Tetrachloride, which I remember fondly because Asbestos burns in it!

Dave

Edited By SillyOldDuffer on 29/10/2022 14:52:20

Come on SOD or are you showing off some obscure knowledge?

The use of fluorine/fluorine compounds may be technically correct regarding burning temperatures achievable but it is hardly realistic stuff to be hauling about safe breaking from within sewers! Especially nasty material to be near

Sorry to be pedantic Brian

A misunderstanding. I digressed into hot burning substances out of interest rather than meaning to suggest they were practically useful for safe breaking! Far too dangerous and - like a Thermic Lance - all too likely to destroy whatever is in the safe.

The film industry is good at spectacle and tends to slide over mere details. For example, a Thermic Lance produces a lot of heat and smoke, so bad in a confined space like a tunnel something elaborate would have to be done to protect the crooks whilst not calling attention to the robbery.

Another method that doesn't work in practice is to bore a hole in the roof, fill the vault with water, and then freeze it. The force exerted when water expands as it freezes is sufficient to burst safes, but the process also soaks and crushes the contents. And before the master criminal can escape with the loot he has to melt a large quantity of ice - not easy to do quickly!

I enjoyed 'Sewers of Gold' though. Anyone know if Albert Spaggiari used a thermic lance in the real robbery? He definitely welded the vault doors shut from the inside to delay discovery.

Dave

when I worked in an industry which used a lot of Fluorine gas we had to attend an induction on its hazards. They hung up a raw pork chop (similar constituents to human flesh) and directed a jet of fluorine at it, whereupon it burst into flames. No source of ignition, no heat, made you concentrate. It is very nasty stuff, which is why industry prefers to use Hydrogen Fluoride, and that's nasty enough in its own right

Hi, as Andrew Johnston has said, oxy-propane is often in industry for cutting iron/steel, and more often in scrap yards, as propane is cheaper, and you don't need to get the metal up to melting point, but you do need a different cutting nozzle, which is a two part one, the inner part being made of brass, and an outer shield made of copper. A thermic lance doesn't need a fuel gas supply, it just needs the end heating up with any type of flame capable to get it up to a cherry red, even a blacksmith's forge will do, and then the oxygen is turned on once it's hot and the reaction will keep going, the lance being a consumable.

Regards Nick.

Edited By Nicholas Farr on 31/10/2022 07:56:23

Anyway, the film itself "Sewers Of Gold" or sometimes titled "The Brain" with Ian Mcshane has been a bit of a favourite of mine since I first saw it as a youngster, but mainly for the final scenes.

As a young motorcycle fan, the sight of Mcshane escaping on the back of a Kawasaki Z1000 and blasting away through the streets and out onto the open roads, with the roar of the big four engine through a 4 into 1 exhaust, was just fabulous.

At least they got the bike right that time!

Unlike Steve McQueen in "The Great Escape" in the famous jump over the fence scene. The supposedly stolen German military WW2 BMW was obviously a 1961 Triumph TR6. It would have been more spectacular on a 1944 BMW I am sure!

My old mate's favourite grouse to accuracy in film and in paintings was scenes of horse drawn carts and carriages on grassy lanes with just the two wheel tracks showing.

regards Martin

Edited By Martin Kyte on 31/10/2022 12:10:57

Robert de Niro used a variant of this idea in The Score; having filled the safe with water from the sprinkler system he lowered an explosive charge into it - his explanation "it's just physics".

I shall look out for Golden Sewers.