Cut & shut - what's the problem?

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Mon 25 Aug 2008 18:52
Cut & shut - what's the problem? - movilogo
If a cruise ship can be extended by cut & shut why there is so much shouting if a car is repaired in that way?

The 'cut-and-shut' cruise ship that was sliced in half to add more rooms
/tinyurl.com/56ssqh


Link to the Daily Mail made non-clickable in accordance with the site policies on links to potentially rival publications.

Edited by Pugugly on 25/08/2008 at 18:55

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Mon 25 Aug 2008 19:00
Cut & shut - what's the problem? - Robin Reliant
Ships are not welded back together under a railway arch in Peckham.
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Mon 25 Aug 2008 19:02
Cut & shut - what's the problem? - Screwloose
movilogo

Very good point; if done properly, I've never seen the problem - or a clear definition.

If a damaged car is rebuilt from the B-post backwards with numerous new pressings, it isn't an illegal cut 'n shut - no matter how badly, or crookedly, it's welded. So what's wrong with using what is essentially a repair section welded to manufacturers standards.

Edited by Screwloose on 25/08/2008 at 19:03

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Mon 25 Aug 2008 19:02
Cut & shut - what's the problem? - Cheeky
Probably something to do with how cars peform in NCAP safety crash tests. I suppose a ship has crumple zones etc, however, the relative forces are very different for each vehicle. Also, a cut & shut car is only as good as the welder doing the work -- no manufacturer standard necessarily.

A cut and shut car can fall to bits on heavy braking, impact, going too fast around a roundabout etc. A ship has nothing relative to its size exterting similar forces upon it.

My twopenneth in any case. My knowledge of physics is particularly poor...!

Edited by Cheeky on 25/08/2008 at 19:05

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Mon 25 Aug 2008 19:09
Cut & shut - what's the problem? - Screwloose
A ship has nothing relative to its size exterting similar
forces upon it.


Apart from the waves of course..... IIRC the highest storm waves ever, reliably, recorded are over 100ft from peak to trough.


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Mon 25 Aug 2008 19:15
Cut & shut - what's the problem? - jase1
Aren't limousines by definition cut-and-shuts?

I agree -- the only real problem with a cut-and-shut is how well the job has been done.
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Mon 25 Aug 2008 19:19
Cut & shut - what's the problem? - Hamsafar
I agree with jase1, plenty of properly done and overt cut and shuts, it's the ones done on the fiddle with stolen cars and wrecks that are the problem.
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Mon 25 Aug 2008 20:23
Cut & shut - what's the problem? - Blue {P}
One of my friends paid £2K for a lovely BMW 320i saloon, lowish mileage and fully loaded with kit on an X reg, the only catch is that's it's a Cat B cut and shut, however, hacing seen the car in the flesh I couldn't find the joins even when I knew where to look and he assures me that having checked it on ramps it looks like the job was done very well.

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Mon 25 Aug 2008 20:40
Cut & shut - what's the problem? - gordonbennet
How does even the most careful welder manage to weld to original standard strong stress parts and roof pillars/sills etc where many of the reinforcing folds of steel are hidden within the outer pressing, and impossible to get to.

I'm thinking here of when i saw the roof cut from a 700 series Volvo, the A and C pillars had many folds and shapes involved inside the pillar, compare to when i saw a modern hatchback (not volvo) roof cut off similarly, even if the volvo is old hat and 'proved' to be weak according to a set up crash test.

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Mon 25 Aug 2008 20:43
Cut & shut - what's the problem? - SlidingPillar
It is possible to do it right, but what you are really doing is building a new car from the undamaged panels of two others. If all the joints are panel to panel using the same kind of repair that you'd do when fitting a new wing say, then the crash-worthiness ought not be affected. Joints mid panel - result could be lethal in a crash.

I do know someone who used to do this commercially, but I don't think it is an economically viable proposition to do properly as a trade these days.
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Mon 25 Aug 2008 20:54
Cut & shut - what's the problem? - Number_Cruncher
>>I don't think it is an economically viable proposition to do properly as a trade these days.

That's right, it can be done properly, but tends to cost more than is commercially sensible.

My father used to keep a project of this sort on the go. Either a serious body repair, or a complete re-shell. When customers didn't show for their appointment, he then had something to allow his mechanics to get on with.

By giving these cars a really good rustproofing while they were apart, these cars tended to outlast cars which hadn't had such a history.



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Mon 25 Aug 2008 20:58
Cut & shut - what's the problem? - oldnotbold
I know that there are several lengthened VW Bay window campers on the road in the UK, but since they were never the subject of an insurance claim, then I'm guessing they are legit.

Frog Island 4x4, amongst others, lengthen Land Rovers.

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Mon 25 Aug 2008 21:19
Cut & shut - what's the problem? - Screwloose

A good few years ago; a cut 'n shut was an automatic, red-ticket, fail on an MOT test. It was certainly a criminal offence to sell one.

When did that change?
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Mon 25 Aug 2008 22:10
Cut & shut - what's the problem? - Simon
Most traditonal cut & shuts are not done by chopping and joining at the manufacturers original seems, but cut more or less straight across and through the original panels into two basic halves. Thus panels are joined and welded in places that they were never originally designed to do.

If you have ever seen a 'usual' cut & shut car that has been involved in a heavy collision and broken back into the two halves, I'm sure you would never ever contemplate travelling in one.
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Mon 25 Aug 2008 22:16
Cut & shut - what's the problem? - none
Some time ago I read a report (AA or RAC) about cut/shut vehicles.
It turned out that in some repairs, the welding was so good and strong that the 'crumple zones' no longer existed.
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Mon 25 Aug 2008 23:23
Cut & shut - what's the problem? - SlidingPillar
There is a world of difference between a naughty cut and shut and making one car out of the parts of two.

The former has a seam line, and the second does not. First might fail an MOT and the second no MOT tester will ever know.
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Wed 27 Aug 2008 18:25
Cut & shut - what's the problem? - GandA
Some time ago I watched a TV programme which featured stretch limos. I can't remember the programme name but it was along the lines of Police Camera, Action rather than a Watchdog prog). It featured a limo that had been hit in the rear and the damage was quite spectacular. The back of the car was virtually destroyed up to the "stretch", or cut and shut, welds. There was very little damage forward of this point. I don't pretend to understand the physics but the weld seemed to act a strong point and reflected the forces back into the rear of the car rather than allowing them to pass through the rest of the car.
Graham G
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Tue 10 Nov 2015 14:01
Cut & shut - what's the problem? - ohsoslow
>> A ship has nothing relative to its size exterting similar >> forces upon it. Apart from the waves of course..... IIRC the highest storm waves ever, reliably, recorded are over 100ft from peak to trough.
>>


Many large ships, tankers, bulk carriers and container ships suffer from structural cracking and some have been lost at sea due to failure, often just forward of the bridge.

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Tue 26 Aug 2008 08:47
Cut & shut - what's the problem? - L'escargot
Welding together the substantial exterior plates, interior plates and supporting structures of a ship (with possibly the addition of additional supporting structures) is somewhat different from welding together (end-to-end) the thin sections of a car body. It's also probable that on its first voyage after the modification the ship was fitted with instrumentation to check its structural integrity. No doubt it also had to satisfy Lloyd's inspectors.

Edited by L'escargot on 26/08/2008 at 08:49

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Tue 26 Aug 2008 08:54
Cut & shut - what's the problem? - L'escargot
No doubt
it also had to satisfy Lloyd's inspectors.


tinyurl.com/5mylm7
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Tue 26 Aug 2008 09:12
Cut & shut - what's the problem? - ijws15
Ships are DESIGNED to be made from numerous plates welded together. Structurally they are as strong as the original.

Cars ARE NOT designed to have joins where most cut-and-shut jobs have them. They are not as strong as the original.
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Tue 26 Aug 2008 09:59
Cut & shut - what's the problem? - oilrag
I saw a Triumph Spitfire in two halves once, the ends about 5 yards apart. That was very early on a Sunday morning just outside Leeds on the M1.

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Tue 26 Aug 2008 10:54
Cut & shut - what's the problem? - Altea Ego
it was made that way
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Tue 26 Aug 2008 11:32
Cut & shut - what's the problem? - Collos25
"Aren't limousines by definition cut-and-shuts?"
No they are normally put on a ladder chassis.
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Tue 26 Aug 2008 14:02
Cut & shut - what's the problem? - Screwloose
No they are normally put on a ladder chassis.


Just like Triumph Spitfires....
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Tue 26 Aug 2008 14:11
Cut & shut - what's the problem? - Collos25
And vitesses and heralds.
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Tue 26 Aug 2008 17:31
Cut & shut - what's the problem? - Altea Ego
>> No they are normally put on a ladder chassis.
>>
Just like Triumph Spitfires....


A rotten ladder chasis
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Tue 26 Aug 2008 14:16
Cut & shut - what's the problem? - zm
AFAIK cut & shuts are not illegal either to sell or to drive. Personally i would not want to drive one or sell one. But given that many car manufacturers will sell you a brand new front bulkhead for a body shell, there must be some good methods of doing such repairs.
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Tue 26 Aug 2008 16:50
Cut & shut - what's the problem? - ianhadden
If I remember correctly, the Peugeot 406 Coupé starts life as a 4 door, nuf said!
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Tue 26 Aug 2008 17:08
Cut & shut - what's the problem? - madf
ALl cars have welded panels in the floor pan. The line of the welds normally does not continue in a line around the diameter of the car - because that weakens the car structurally.. The roof panel is one peiece front to rear and this gives strength and some dgree of torsional rigidity.

A cut and shut car tends to have a line of welds all around the car's diameter.. including panles never intended to be cut and rewelded.. eg floorpans.



Apart from anything else the flexing of the welds will tend to destroy seam sealant over the welded panesl and induce rust when water creeps in...


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Tue 26 Aug 2008 17:12
Cut & shut - what's the problem? - Number_Cruncher
>>A cut and shut car tends to have a line of welds all around the car's diameter

That's a badly done one. They can be done properly, unpicking, and replicating the manufacturer's original welding lines. But, that's expensive to do properly.

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Tue 26 Aug 2008 19:58
Cut & shut - what's the problem? - Lud
I dislike and would distrust any car lengthened beyond the longest factory spec, however well the work had been done. However a normal bodyshell extensively repaired to original or better spec seems quite all right to me.

Mercedes 600, RR Phantom or Cadillac tycoon's limo, yes. Stretch thingies, never. As for the thing the US President rides in these days, do me a favour. It's grotesque.
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Wed 27 Aug 2008 08:44
Cut & shut - what's the problem? - L'escargot
At the factory car bodies are spot-welded together with overlapping seams. Cut & shut (often) have panels gas welded end-to-end, and the parent metal melts. Sometimes the parent metal will run away from the gas flame and result in a hole which is then built back up with the welding rod. End to end welding results in a weak join and can also affect the metallurgical structure of the metal at, and close to, the join.
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Wed 27 Aug 2008 15:08
Cut & shut - what's the problem? - skorpio
I've just seen one of those new Mini Estates in the flesh. That looks like a cut 'n' shut to me!
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Wed 27 Aug 2008 15:34
Cut & shut - what's the problem? - Collos25
And they put the rear door on the wrong side in the hurry.
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Wed 27 Aug 2008 15:44
Cut & shut - what's the problem? - Mapmaker
I think they're stunning. (But I wouldn't pay 12k... or whatever they are.)
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Tue 10 Nov 2015 11:42
Cut & shut - what's the problem? - Automania

The difference between factory fresh and molested vehicles grows at a pace in line with human variety.....diverse.

There are clinical quality checks on integrity of metals, welds, alignment of each panel in todays modern cars.

We have a superich that change motors like shoes.

We have immigrants that would be grateful to drive anything, cut shut, smacked, stolen, dragging down the road friring on one cylinder.

We also have a rebellious middle class that drive rodded, redneck, super pimped, rat rods, custom cars who would spend months ribbing you folks about health and safety over weld lines. By nature they are desirable as a weld is a statement.

It is a slight grey area to be able to drive a cab and chassis - ladder frame vehicle and ignore the bodywork integrity but available for truck, limos and 4x4 style fun.

I would not be driving a smart car no matter what the claims of integrity.

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