plexiglass to guard MH bulbs???

[fedukeford]

"Glass or Plexiglass Splash Shield - A must for metal halide lighting. Metal halides get extremely hot and one drop of water could cause the bulb to explode. A tempered glass splash shield will also help to filter out UV rays as well, usually required when using HQI metal halide bulbs."

has anyone found this true? do you have any glass or plexi galss guarding your MH bulbs? or is it just open over the tank?

thanks

 

[Paul B]

There is "special" quartz glass on MH fixtures because of the heat. Plexiglass would melt. Quickly, I would imagine.

 

[zanclus]

I have my bulbs open to the air but they are also 14" above the water. Plexi would melt if not warp with the heat of MH. I did once shatter a brand new ushio 10k when I first set up my halides splashing water on them .after that $70. mistake I am much more careful!!!

 

[fedukeford]

paul B- is that for retrofit kits?? or the hoods with like MH's Vhos and Pc's??

 

[friendlyAlien]

I have the same question ... so ... I tagging along ...

 

[M. Python]

I have my bulbs 5 inches away from the water. NOT RECOMMENDED. But I have never had them shatter, they do get salt on them. I only had one accident when I bumped a lock line out of the water with a rock and it hosed one of my halides, it exploded but no damage other then having to get a new bulb. My tank has run like this for over five years with only the one incident that I caused being careless. Safety first! I should have turned off the halides and waited for them to cool. Not only preventing the explosion of the bulb but also to prevent burns. I have bumped a bulb, they leave nice scars to add to my collection. The skin just falls off, no pain due to the nerves being destroyed on contact. You know when it happens, all you hear is PSSSSSSSSSSSSSSSSS..........................

 

[Paul B]

fedukeford. I don't really understand the question but you can't put plexiglass anywhere near a MH lamp. I am an electrician and there is special quartz lenses on MH fistures so the rain does not break them. I also do a lot of work with plexiglass and even though plexiglass does not really melt easily it will sag and warp with even a little heat. A little more heat and it burns.
Why would you want plastic near your lights?
I would imagine there is some type of plastic that some MH fistures come with but if there is, it is not plexiglass.
Paul

 

[friendlyAlien]

where do you get this quartz?

 

[Paul B]

You don't get it. It comes with MH fixtures. If you are building the fixture yourself you may have to leave the bulbs bare. Unless someone else knows where to get it. You can use regular tempered glass, just don't splash water on it when it's hot.
Paul

 

[Gary Majchrzak]

My fan cooled PFO MH fixture came with a plastic shield.
I'm not sure exactly what type of plastic, but it was thick.
It didn't warp or melt, but I replaced it because over the years it got permanently scuffed up with salt spray.
The thinner plastic I replaced it with worked well for several years, but it started to warp over time from heat.
I replaced it with glass.

In DIY MH fixtures you need to keep the halides high above the water and run a fan. Coat the inside of any wooden fixture to protect it, or heat and humidity will destroy it in a few years.

 

[dalbrecht]

Unless specially coated the plexi won't do as good a job of blocking UV that the glass does. This can be a pretty big deal in some setups