DIY metal halide canopy

[Travis55]

So my mh fixture is uuuuggglllyyyy. Can i build a wood canopy to go around the fixture? It holds 2 175w bulbs and 2 t5 ho.

 

[ccCapt]

I would pull that tin foil off. It will only scatter the light around. You will get better results with the flat white metal only.

 

[jondamon]

I would pull that tin foil off. It will only scatter the light around. You will get better results with the flat white metal only.

I agree completely about the flat white being better than the tin foil.

One thing I would be concerned with would be the build up of heat if you encased the whole fixture in wood.

Something as simple as a PC fan blowing through the wooden enclosure to remove the heat would work.


Jon


(I used to use these lights to grow stuff in another life 600w versions). Lol.

 

[Travis55]

I agree completely about the flat white being better than the tin foil.

One thing I would be concerned with would be the build up of heat if you encased the whole fixture in wood.

Something as simple as a PC fan blowing through the wooden enclosure to remove the heat would work.

Jon

(I used to use these lights to grow stuff in another life 600w versions). Lol.

I think the foil put more light down... but thats just me. Im still hunting for some cheapie reflectors. Anything better than what i have.

Also i scavenged these out of a minifridge. Heat sinks and all.

 

[jondamon]

The foil will appear to direct light downwards but unless you have ZERO creases in the foil it won't spread light evenly.

There are films on the market that you can use.

Mylar, diamond reflective sheeting , orca film etc.

 

[Travis55]

The foil will appear to direct light downwards but unless you have ZERO creases in the foil it won't spread light evenly.

There are films on the market that you can use.

Mylar, diamond reflective sheeting , orca film etc.

What about chrome spray paint?

 

[jondamon]

What about chrome spray paint?

To be honest Travis55 you would have difficulty keeping chrome paint even and it probably wouldn't obtain the same reflectivity as leaving it white.

Keeping it white as it is you should be getting around 80% reflectivity.

Tin foil with zero creases around 85% reflectivity.


Chrome paint with even coverage maybe if you're lucky 85% reflectivity.

However with chrome paint I would be concerned with offgasing.


Seriously I would leave it white as it is, I used to use diamond reflective sheeting on walls. My reflectors that housed my 600w lamps used to have a bubbled aluminium reflective panel above them but it was also computer designed to give the best spread of light downwards.

With metal halide lamps have you thought about water splash on the glass tube?

The reason I ask is that MH Lamps use gasses to ignite and keep the light spectrum you need and they burn hotter ALOT hotter than T5's T8's etc so a small amount of water on the glass tube could cool the bulb too much and cause a blow out.

This would obviously depend on the proximity of the MH to the water level.



Jon

 

[Travis55]

To be honest Travis55 you would have difficulty keeping chrome paint even and it probably wouldn't obtain the same reflectivity as leaving it white.

Keeping it white as it is you should be getting around 80% reflectivity.

Tin foil with zero creases around 85% reflectivity.

Chrome paint with even coverage maybe if you're lucky 85% reflectivity.

However with chrome paint I would be concerned with offgasing.

Seriously I would leave it white as it is, I used to use diamond reflective sheeting on walls. My reflectors that housed my 600w lamps used to have a bubbled aluminium reflective panel above them but it was also computer designed to give the best spread of light downwards.

With metal halide lamps have you thought about water splash on the glass tube?

The reason I ask is that MH Lamps use gasses to ignite and keep the light spectrum you need and they burn hotter ALOT hotter than T5's T8's etc so a small amount of water on the glass tube could cool the bulb too much and cause a blow out.

This would obviously depend on the proximity of the MH to the water level.

Jon

The fixture will be 8-10" away from the water