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SuperSharpies burning through spansets


timmeh2

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Hello BR

 

Maybe a repost (please delete / call me an idiot as appropriate) but this popped up on my bookface wall so I thought I would share.

 

All the best

Timmeh

 

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This is the result of the new Super sharpie being 7M away. It's deemed that it only takes seconds for this to happen and the same issues are happening with soft span in areas where they still use softies to raise truss. With the advent of all the new super lights like the super sharpie we need to look at safety in a new light.

I have just had an issue with a chain bag melting at 7M away from the light source on

So we did a little test....

From 7M away the chain bag was smoldering in 15 seconds

The spanset with 12KG hanging on it took 15 seconds to burn to the nylon inner core.

In Europe and the middle east GAC flex is not common place and people still hang trusses on spansets , I would advise riggers to find out what lights are in the rig before making any decisions and survey the rig during the focusprocess to ensure no unforeseen disasters and fires...

Food for thought ......

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Food for thought possibly. Although the damage to the chain bag in that picture does look more mechanical to me. I'm not wholly convinced that post is entirely genuine.

 

I don't think this happened from a super sharpy at all. If it were damaged by heat, you would not expect to see the fabric around the edge of the hole frayed, you would expect to see it melted together.

 

That said, what this might be is a hole created by a super sharpy, and then the whole somewhat enlarged by the chain going through it - if the bag was full when melted.

 

But as I've previously posted, I have held a blow torch to a loaded spanset and it took several minutes to melt through it. That's a blow torch, a direct source of a lot of heat, very close. So, sorry to the OP, I have absolutely no belief that a moving light can do it in 15 seconds.

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Clay paky had some super sharpys at floor level at Plasa, I put my hand in the beam to check how hot they were, and it was hot but didn't burn my hand or anything. That was a couple of metres away so I don't see how this could happen at 7 metres.
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Clay paky had some super sharpys at floor level at Plasa, I put my hand in the beam to check how hot they were, and it was hot but didn't burn my hand or anything. That was a couple of metres away so I don't see how this could happen at 7 metres.

 

If you had a matte black hand you may have spotted the difference!

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So we did a little test....

From 7M away the chain bag was smoldering in 15 seconds

The spanset with 12KG hanging on it took 15 seconds to burn to the nylon inner core.

 

This is surely something the destructive types on the Blue Room can test. Who's got some Super Sharpys in the warehouse or on a show and could test the heat in the beam?

 

I've seen that video of frying bacon with Sharpys but that was quite a few sharpys at close range and took a few minutes. Burning in 15 seconds at 7m distance... just doesn't sound possible.

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This is surely something the destructive types on the Blue Room can test. Who's got some Super Sharpys in the warehouse or on a show and could test the heat in the beam?

 

I've seen that video of frying bacon with Sharpys but that was quite a few sharpys at close range and took a few minutes. Burning in 15 seconds at 7m distance... just doesn't sound possible.

 

I had some faux sharpies on an event (not even good imitations, they had a 2-3deg beam) - they were under a 1" lexan stage and 1m away from a kabuki drop. It started to smoulder within seconds if they were turned on before the cloth was removed, so I certainly believe it.

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I had some faux sharpies on an event (not even good imitations, they had a 2-3deg beam) - they were under a 1" lexan stage and 1m away from a kabuki drop. It started to smoulder within seconds if they were turned on before the cloth was removed, so I certainly believe it.

 

1m is very different to 7m though. You'd be setting fire to the stage floor with the rig at trim height.

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Whether the post is true or not, I have melted a hole the fabric of a chair in about five minutes with a Rush MH3!

It certainly made me think about how I use those type of fixtures now!

 

No doubt about that. The LSD Icon (which is going back a ways now), had a weird focal 'hot spot' about 2' in front of the lens. It was a common party trick at the time for lampies to light a cigarette on it. A fair bit of Marley was ruined in the early days as rigs were powered up at working height.

 

Contrary to the text of that post, GACflex (Steelflex/Softsteel/etc..) is fairly commonplace throughout Europe, and becoming more so. Though Spannies are still used, obviously.

 

That post (which I'm still taking with a big pinch of salt) skates straight over the issue of the chain bag itself and on to SpanSets. A chain spill is not a trivial event, and I don't see any proposal to replace the chain bag with a steel box (thank goodness), so if this is a genuine issue then care with the lights is called for regardless of how the truss is slung.

 

By the by if a chain spill initiated at the top of the gaping hole pictured, that bag was too full - not big enough for the hoist it was attached to. That's something that gives cause for concern from time to time. Klein buckets being largely phased out and replaced with ARS (and ARS-style) bags oven the last few years has improved things greatly, but chain spills are still way too common.

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...and it's worth pointing out that any heat source capable of causing such significant damage to a soft spanset is also going to do some significant damage to a metal set; not as quickly but still some serious damage. Since this hasn't been mentioned ANYWHERE else except relating to the posting above and as others have pointed out the whole thing seems very suspicious I remain thoroughly unconvinced.
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...and it's worth pointing out that any heat source capable of causing such significant damage to a soft spanset is also going to do some significant damage to a metal set

 

In the general "what happens if the building is on fire!?" sense that used to be trotted out fairly often as a reason why SpanSets shouldn't be used, I agree completely.

 

Not necessarily the case with a very localised heat source though. The issue is as much to do with the thermal conductivity of the sling as anything else in that a very localised heat source will result in very localised heating.

If you put your mind to it, you could quite easily cut a polyester round sling with a soldering iron. Beyond trashing any plastic coating (or the outer sleeve of a GACflex sling), not so with steel.

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