An unexpected danger from tyres

[JohnD]

All,
You might never think of doing a bit of welding on a damaged wheel, but if you did, it could kill you!

Have a look at this thread, over on the Sideways Technologies board:

http://sideways-technologies.co.uk/f...638#entry75638

John

[JimW]

Anyone who welds a wheel with an inflated tyre really is shooting for a Darwin award.

Think of it as cleansing the gene pool.

Regards

Jim

[JohnD]

So it is, Jim, but you don't have to talk in words of one syllable, and say 'Innit?', to be ignorant of this danger!
I would have thought that I might damage the tyre, not myself. The idea of 'pyrolysis' and an explosion just wasn't on my horizon.

It's strange that some Health'n'Safety ideas get passed from industry to the general population, and some don't. This danger is clearly well known in industry, as well as you, but though I am concerned with safety this is a new warning to me. When amateur welders like me can get good advice on welding safety and apply them, why is this a lesson that gets left out?

Any other good tips?

John

[JimW]

No welding tips John.

This seems to me to be one of the areas where there may be a tendency for common sense to be insufficient and some training or, at least, a requirement that anyone who is going to use welding equipment has to have acknowledged the need for understanding, perhaps even training.

No one would ever accuse me of being over-keen on the full rigour of some H&S approaches but stored energy and heat ought to be a warning to anyone.

So, do we think that B&Q ought to be able to sell welding equipment to anyone? More energy that a shotgun shell but no requirement for training? Personally I do think they ought to be on open sale but that may not be a universal view. Perhaps one trouble would be the "gold-plating" of the requirements which would follow any regulation. NVQ anyone?

Regards

Jim

[Tim Falce]

Originally Posted by JimW

Anyone who welds a wheel with an inflated tyre really is shooting for a Darwin award.

Think of it as cleansing the gene pool.

Regards

Jim

That's similar to the woman that had bulge on a tyre sidewall so carried it on her lap in the back of the car where it exploded and killed her. I suppose in some cases you have to have seen or experienced these dangers to realise they are there.

[midgetman]

The sobering bit is that you don't have to be doing anything stupid like welding a wheel with an inflated tyre. Let the air out and heat up the wheel nuts could still be enough, and 22 hours later!

Catch 22. You can't apply heat to the nuts without taking the tyre off and you can't take the tyre off without applying heat to the nuts.

Perhaps it's a good job that the world is full of stupid people to do the the jobs we are too clever to undertake.

[RPD Motorsport]

The issue is with the heat causing pressure increase inside the tyre beyond what the wheel/tyre can contain.

If you need to heat the wheel nuts its fairly normal to remove the valve. That way pressure can not build up at all and your safe.

[JimW]

Originally Posted by RPD Motorsport

The issue is with the heat causing pressure increase inside the tyre beyond what the wheel/tyre can contain.

If you need to heat the wheel nuts its fairly normal to remove the valve. That way pressure can not build up at all and your safe.

Compare this advice with that in the video referenced in the first post. Seems it cam bite you either way.

Regards

Jim

[JohnD]

Originally Posted by RPD Motorsport

The issue is with the heat causing pressure increase inside the tyre beyond what the wheel/tyre can contain.

If you need to heat the wheel nuts its fairly normal to remove the valve. That way pressure can not build up at all and your safe.

If think it is a bit more than just the Gas Laws working, and pressure increasing as temperature rises. My (non-chemist, no knowledge of tyre technology) reading is that the initial heat produces "pyrolysis", the chemical breakdown of the rubber compound, releasing gases that increase pressure. The incraesed pressure produces heat, that drives the reaction that produces heat itself. A positive feedback, runaway reaction that inflates the tyre beyond it's yield point, when BOOM!

John

[JohnD]

Tragic confirmation of this hazard.

http://www.dailymail.co.uk/news/arti...odes-face.html

The news report says he was "using a high-pressure air hose" on a tractor tyre, but on another message board a local says that he was using heat to free a seized wheel nut of an 8-wheeler forestry truck.
And as this was a blacksmith, shows that either lesson isn't well known.

John

[RPD Motorsport]

Yes the tyre break down also contributes...

But my point was whenever you need to mess with a wheel/tyre unit remove the valve core to prevent pressure build up whatever the cause.

[midgetman]

The video clearly says that the valve is not sufficient to let out all the pressure and cited an example. In one extreme case, the tyre even re-seated itself!

[GORDON STREETER]

Originally Posted by midgetman

The video clearly says that the valve is not sufficient to let out all the pressure and cited an example. In one extreme case, the tyre even re-seated itself!

The hill climb boys in Iceland and AUS ignite butane fuel inside their tyres all the time to re seat them on those 4x4s when they come off the rim
http://www.youtube.com/watch?v=V4xahazg58M

[JohnD]

And the Aussies quickly put the valve back in!
Of course, you have to be an Ocker bloke for that to work.
If you're not, this happens:
http://www.youtube.com/watch?v=fO9M6...eature=related


Which leads me to this video.
The parent of the poor child should be shot:
http://www.youtube.com/watch?v=JV3zB...eature=related

JOhn

[GORDON STREETER]

Originally Posted by JohnD

And the Aussies quickly put the valve back in!
Of course, you have to be an Ocker bloke for that to work.
If you're not, this happens:
http://www.youtube.com/watch?v=fO9M6...eature=related


JOhn

I think they might have used a "little" bit too much.
Agreed some people haven't the sense they're born with, like my rant on the moan thread

[Peter Mallett]

Hmm,

We lost three idiots who did that. One of them left a lasting impression in the roof of the shed they were working in. And guess what? Two days later, our safety guys stopped another bunch of idiots doing the same thing.