[organicreefer]

anybody made one?how?out of what?id like a four foot reflector to hold all three of my halides.something simple,maybe a peice of sheet metal "folded "to a half round shape?any ideas/help appreciated

[MarkS]

Check out: http://www.aquatictech.com/lighting.html

Scroll down to the bottom. They sell spectral aluminum in 12"x48" for $20. They only charge $1 per fold.

[organicreefer]

thanks alot mark!

[scubadude]

I went to HD tonite and came up with some fairly cheap pieces of flashing (it looks almost identical to spectral alum.) and am gonna attempt to build my own reflector....found some really neat stuff that should work great....if your not in a hurry then wait!! I will post pics of the stuff i got and some Ideas i came up with I called aquatictech today and wanted them to fabricate my custom reflector (they have a caption under the spectral alum. that says we can build any reflector), and mine was fairly simple yet they didnt want to build it....so im on my own on this one!

[organicreefer]

scuba ,i just received a letter back from aquatictech,and they dont want to build mine either,looking forward to those pics

[scubadude]

Go to home depot and go to the roofing supplys and if you cant find it then as for aluminum flashing for roofs. They should have rolls of it....you can either do like me and buy a roof panel (thats the long piece that looks like a spider reflector) get some really good snips to cut this stuff with....and I recommend wearing leather gloves cuz the stuff is Razor sharp! I was gonna post pics of the status of my reflector but im still in the works on it.....this will atleast give you something to ponder on.

[scubadude]

ontop of the Dark Green trash can that is a Roll of flashing its 10" x 10' which is the size i wanted....that have all kinds there....and the stuff is REAL easy to bend....just dont get it too thick and grab your snips in HD if you dont have them and test cut a small corner of the flashing to make sure they cut good HTH

[organicreefer]

hmm, that roof panel looks interesting,couple bends /unbends and it would be kinda like a spiderlight ref.,whats youre plans for that thing?i know youre still working on it but update as soon as you can i want to finish the reflectors so i can post pics of my new hood,im pretty proud of it

[icemark]

Actually that flashing won't work that great... while yes it is flexible and easily bent; the refective quality is rather poor according to Sanjay's latest testing.

You would be much better off using the White coated version of that same flashing, or if you want to keep what you have; get some polishing compound and a good orbital buffer and start shining it up. (which is what I do for my DIY hoods).

The aluminum flashing by itself you'll notice has small scratchs in the surface and is not mirror smooth. Spectral Aluminum is much more mirror like.

[dattack]

I agree. I use the aluminum flashings also but the reflective property is even less than a painted white hood. The only use I could find for them was as a grounding material although I am uncertain to if it could do that job also.

[Mobious]

If you are going to use this reflector in a hood.. why not just do away with it and paint the inside of the hood white?

[scubadude]

can someone give me the link to sanjays report on the reflectivity of the flashing and other materials?

I would appreciate it

[dattack]

Try this study and look under featured articles, especially the one on reflective materials.

http://www.reefs.org/library/aquariu...ers/index.html

[scubadude]

Heres the deal....all of the mentioned items are good quality materials for reflectors! However each one has different characteristic for example if you look in the charts polished/specular alum. has better reflectivity than flashing, however it does not have as good of a diffusion percentage as the flashing....so I guess this is all depending on what you are looking to get out of your reflector amongst other variables....for example HQI lights are known to have not near as much diffusion as regular mogul MH's .....since im going with 3 HQI's in my hood wouldnt it be better to have a bit more diffusion then reflectivity? just a thought....u guys have made me stop right in the middle of my reflector making process and rethink....but im not sure if im picking the fly poo poo out of the pepper here! (a southern boy saying) Maybe I will try to fire the bulbs with the flashing and see how it looks....and if i dont like it then buy some spectral alum.

[scubadude]

I had to refresh myself and look in the Dictionary mahself :P

Specular - Of, resembling, or produced by a mirror or speculum.

I would think that this concentrates the lighting just on the area beneath the bulb!

Difuse - To spread about or scatter; disseminate.

So if the reflecter is bent/angled correctly wouldnt this help spread the lighting to all of the tank area...and not outside if the reflector is bent/angled correctly

[dattack]

I am in no way a light expert but what I got from the article is that white paint is about equivalent to aluminum flashing in terms of reflectivity (diffuse). The only problem will diffuse reflectivity which is inherent in white paint/aluminum flashings is that the light is reflected at no particular angle and has no particular focus.
Let's say you use aluminum flashings and bent it to to shape to fit your needs. You would have light bent at random bouncing around your reflector. The loss of light would be in fact the light that has been absorbed by the lamp and the fixture itself. So much of the light lost would be through restrike. The diffuse reflecticity of this light is pretty much random and lost of light will be noticeable.
If specular aluminum is used, the light will inevitably follow a nice path because incident flux's angle is the same as reflective flux's angle. Therefore, your light will not be bouncing around like crazy and restrike something in the canopy that will absorb the light.

I don't have HQI so I am not sure if there is much restrike with them given that it is a smaller fixture? A metal halide bulb on the other hand is a big bulb and can absorb most of the light that eventually bounces back to it. So the key thing you need to know is how much of the light will be absorbed back by your fixture. Therefore, you want to find a reflective material that can be easily clean off with there is salt on it and one that doesn't corrode.

[organicreefer]

this paragraph near the end caught my eye:

Further complicating matters is the fact that the light source plays a significant role in determining the best reflector criteria. A tank lighted by a quasi-point source light like a metal halide bulb requires greater diffusion than a tank lighted by a source that already diffuses the light, such as a fluorescent bulb. This is one irony of the evolution of reef tank lighting. Fluorescent lighting has traditionally relied on white reflectors that end up further diffusing already diffused light. Metal halide lighting has generally used polished aluminum, which focuses an already focused light source. It would appear that perhaps the hobby has not optimized either light source.

[dattack]

Yes, it is somewhat a confusing paper. He goes to say aluminum flashing sucks yet it is a good diffuser in terms of a good point light source.
I have read Sanjay's paper somewhere but am unable to find it. Anybody have the link?

[scubadude]

Im still playing around though too....I have tested and love the spread!

[dattack]

Looks good to me!