Old car body repairs - advice sought...

[Grunff]

Well, yes and no. Yes in that it contains a huge amount of stored energy, which if released quickly enough can have some very unpleasant consequenses. No in that it's actually pretty difficult to get a cylinder to explode.

When I used to do a lot of lab time, I saw many instances of cylinder abuse. The two most memorable incidents resulted in a) a cylinder tumbling down two flights of stairs, and b) a whole bunch of cylinders falling off a lorry. No cylinders exploded on either occasion.

The department's safety officer, who had been doing the same job for some 35 years, and had seen far more accidents than I had, couldn't recall a single cylinder failure in all his time at the unoversity. He said that valve failures were pretty common though.

Given this, I can't think of many things a home user could do to cause a cylinder to blow - except maybe torch it!

[:::Jerry::::]

You wouldn't but those who know what they are talking about will, as I've said in another message this is my trade so please don't tell me what should and shouldn't be done, As for the filler, on another part of the xar you would have at least a 50/50 chance but on a door there is little chance of it staying in place, it might not drop out but it's ver likely to crack and allow water in behind - even with so called dlexable fillers that are around these days..

Still means something has been skimped on....

Well that would depend on what paint is being used and has been used in the past not to mention what it's condition is, sorry but you can't advise on this sort of thing blind - other than to say strip it back to bare metal.

[Andy Dingley]

Garage fire will burst an oxygen cylinder, unless the brigade get a hose onto it and cool it.

I found a burnt-out and ruptured O2 cylinder a while ago. I thin there had been a car fire on top of it - hopefully the local chavs took some shrapnel when it went. If I'd not been cycling I'd have dragged it home and made something from it - splendid "banana peel" split down the side.

[:::Jerry::::]

< Rhetorically speaking >

Oil the valve of the Oxygen cylinder ?..... < /Rhetorically speaking >

[Grunff]

Makes you wonder how that situation came to be. Where they got the cylinder from, how they got it there, whether they did it on purpose...mind boggles.

[Pete C]

OK, what about epoxy resin and fibreglass cloth? Epoxy sticks very well to bare metal, it's used to line drinks cans to stop the contents reacting with the aluminium. It also has a long history of use in boat building and repair.

I'd agree that it's better to mig in new metal but depending on the skill/facilities available and the value/lifespan of the car it's not always worth it.

cheers, Pete.

[dave]

Try

Its an American forum for 4wd Mk1 passats which they call Quantum syncros. They are the same body style as the GL5 of your year. Although they based in the U.S I know there is at least one guy from Lincon whose username is Scot. He responded to my post for parts so it might be worth a browse.

[:::Jerry::::]

And it also has a long history of cracking and crazing, doors [1] flex far more than any other part of the bodywork and if the frame it's self is weak things get far worse.

[1] when I say doors, I also include tail gates.

Then it is not worth doing at all, a fibreglass repair could be breaking up within the year, time and money wasted....

It would be better to spend the money on having plates welded in and then finish off with something like 'Bondaprimer' and say "sod it" to the way it looks IMO.

[Richard Porter]

It's the ascetylene ones that are really nasty. If they're knocked over or involved in a fire you have to play water on them for 24 hours because the stuff is so unstable.

[Mark]

LOL Now I have heard it all. Try explaining that one to Mr MOT inspector. when you have Brazed a patch on something as Non-Structural as a sill.

[:::Jerry::::]

Are you SURE about that, and if you are perhaps you can direct people to an online (or 'hard') copy of the H&S etc. rules etc. relating to the use and safety of Ox-acetylene equipment.

[Richard Porter]

No, but I know it's what the fire brigade does if they're dealing with acetylene cylinders in a fire, and they'll evacuate neighbouring houses. Actually I have got some safety guidelines from a welding course I did but I'm not going to dig them out now.

[Grunff]

Hmm...

The acetylene bottles are at much lower pressure than the o2. This is because the acetylene is dissolved in acetone, which is in turn adsorbed onto clay powder.

I don't buy your 24 hour assertion.

[Andy Dingley]

Not if they do finally explode - nasty, but much smaller blast radius.

The cooling schedule for both after a fire is similar.

[:::Jerry::::]

I suggest you do look them out, certainly before you go near any Ox-acetylene equipment....

[Andy Dingley]

In some ways oxygen is safer, because if you don't annoy it, it won't annoy you. An oxygen cylinder will not _spontaneously_ explode, it needs some external interference to cause it.

Acetylene can get into an explosive state all on its own. An initial accident and root cause may be as minor as a welding flashback. Nothing obviously happens, so the operator thinks that it's "safe". A few hours later the building explodes.

Even a relatively minor perturbation of high-pressure acetylene can cause the cylinder contents to begin decomposing. If the cylinder isn't cooled with a hose, cooled quickly, and cooled and monitored for many hours afterwards, then it's almost guaranteed to explode. A cylinder that's getting warm on its own, is making a noise, or is vibrating (!) is in a really dangerous state. It usually takes a few hours before the explosion, which is time to deal with it. However some famous examples (there's one on the front of the HSE acetylene leaflet) have happened in minutes.

I've heard it said that if an acetylene cylinder is warm, you ring the fire brigade. If it's already vibrating, you just run like f*ck right then and don't stop for anything !

[mike]

where any fire involves acetylene cylinders, for the past few years it has been standard practise for the fire brigade to establish a 24hr 100metre radius exclusion zone, to the degree of closing roads (and in recent memory, a railway line) and evacuating houses - believe me, because i've been stuck in the ensuing traffic jams

[Richard Porter]

If you want to be helpful post something useful.

Btw, the '24 hours' isn't an assertion on my part, I'm just telling you what I've heard reported. I expect in practice it could be a longer or shorter time before the cylinders are deemed safe.

[mike]

I've been delayed twice in the past 12 months - fire near cylinder in a works yard - A576 closed for the full 24 hrs shed containing cylinder caught fire. The shed was at the rear of some houses that fronted on to the A58 - A58 shut for the full 24 hrs thats' the Greater Manchester Fire Brigade

I also found the following on West Sussex' FB website - 'Because of the explosion risk, the main south coast railway line that runs past the building had to be closed, causing major disruption for rail travellers. A safety cordon of 200m had to be sealed off and a number of businesses on nearby industrial estates were also evacuated in an operation co-ordinated by Police. We are working hard to minimise the disruption being caused, but because of the volatile nature of acetylene cylinders when involved in fire, firefighting operations will have to continue for a period of 24 hours, before we can be satisfied the cylinders are safe to move, and premises will be able to reoccupy'

[N. Thornton]

If all you want is an MOT pass why not just stick cloth tape over it, then its legal. (That wont apply to structural stuff of course.)

Best option is replace the doors, but if you cant, its a matter of metal sheet and weld or rivet, preferably weld.

NT