Yikes. Is this normal for a MH bulb?

[BlueDevil]

Broke out my Sunmaster 400W MetalHalide bulb the other night in a bid to get ready for some pre-spring sproutin.

I noticed the inner bulb has accumulated a white phosphorous like coating on the top and bottom thirds of the structure, but everything else within the glass (wires, fuse, etc) seem fine. Is that build up normal?

I plugged it into my Lumatek digital and sure enough it began it's incremental fire-up like everything was fine. This ballast will supposedly remain off if there is a problem detected with the bulb.

Anyone else experienced this before? Is this something I should be worried about?


tia!

BlueDevil Reviewed by BlueDevil on 02-14-2008. Yikes. Is this normal for a MH bulb? Broke out my Sunmaster 400W MetalHalide bulb the other night in a bid to get ready for some pre-spring sproutin. I noticed the inner bulb has accumulated a white phosphorous like coating on the top and bottom thirds of the structure, but everything else within the glass (wires, fuse, etc) seem fine. Is that build up normal? I plugged it into my Lumatek digital and sure enough it began it's incremental fire-up like everything was fine. This ballast will supposedly remain off if there is Rating: 5

[Mr. Clandestine]

I'm pretty sure that stuff is just a residual substance from one of the chemicals used inside the arc tube. I've seen that in both 400W and 600W conversion bulbs that I used in the past, and all seemed to operate just fine for me. I've also used both Sunmaster and Hortilux conversion bulbs, and they both had that same residue. Nothing to worry about, as long as it's lighting up, you're good to go! :thumbsup:

[BlueDevil]

*whew*

I was hoping to hear that. Not exactly a topic I was willing to broach with my local hardware store know-it-all...
That's what I was leaning towards as well, although my nagging pessimistic side kept whispering things to the tune of 'That means it's about to reach critical mass! Get ready for a fire!'

Much appreciated sneaky one, you've set my mind at ease. :thumbsup:

[Mr. Clandestine]

That's what I was leaning towards as well, although my nagging pessimistic side kept whispering things to the tune of 'That means it's about to reach critical mass! Get ready for a fire!'

Haha, I had a pretty similar reaction initially, along the lines of: 'I paid dearly for this thing, waited TWO weeks for it to arrive, and now that it's here, it looks BROKEN...or used!' To this day I've yet to have any mechanical issues with the bulbs. Similar to your ballast, many MH bulbs are also designed to experience passive failure (or self-extinguish) if the outer envelope is cracked, or if there's something else wrong with it. But even those that aren't designed with any safety features probably won't experience sudden nonpassive failure (rupture/explosion) unless you severely mishandled the bulb beforehand (i.e. - clubbed someone over the head with it... intentionally sprayed it with Windex while still hot... etc.)

Much appreciated sneaky one, you've set my mind at ease. :thumbsup:

Aye, glad my sneakiness could be of service!