Exploding Par 64

[smyles]

Just come in to a venue with an orchestra and during a rehearsal one of the par 64's overhead exploded, with a shower of glass, but continued to work. On closer inspection it appears the lens on the front of the lamp has been blown out, but the capsule inside is still intact so it continued to light.

The tech here informed me a few have been doing over the last couple of weeks.

 

Never seen this before, is this likely to be a dodgy batch of lamps?

[timsabre]

Could be. Could be something on the lens e.g. Dead fly stuck to it or something like that. I've seen them explode occasionally, it's usually water drips when in use outside, but I have seen a couple go for no apparent reason.

[Dave m]

They do go with a bang!

[Roderick]

Or could it be that the lamps are inserted incorrectly?

If something is preventing the lens to expand when it gets hot, it will scatter.

Try testing all PAR64's and see if the lamp turns easily.

[ianknight]

Check all your retaining rings in the PAR's - someone's been overzealous and pushed them in tight to the PAR unit. I had something similar with hire stock a few years back - one of the prep guys didn't realise the rings were supposed to have a looseness to them & we lost three units because the glass couldn't expand as the unit ran :(

[gareth]

Ian's dead right about checking the retaining rings. If the lamp is clamped too tightly into the unit it won't have the freedom of movement that it needs in order to expand and contract with the change in temperature. I used to fight a continuous (and generally losing) battle to educate some of my ex-colleagues about the fact that it's a lamp retaining ring and not a lamp clamp!