# DIY Reflectors?



## jorgeimbacuan (May 31, 2006)

I am looking for a DIY reflectors for fluorescent lamps.

Any info are welcome.


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## John N. (Dec 11, 2005)

The only DIY reflector I've made was painting the inside of the bulb reflection surface area with white paint. It was easy, and worked pretty well at getting more light into the tank. Plants "pearled" with the DIY job, where it had not prior. 

-John N.


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## hoppycalif (Apr 7, 2005)

There are two problems to solve in DIYing a reflector. First is to shape the reflector so that it redirects the light from areas of the bulbs that aren't "seen" by the water down towards the water. The second is to get a reflector surface that reflects 90% or so of the light striking it in the direction you expect it to go. You can use a piece of paper, a straight edge and a protractor to figure out how to shape the reflector. The reflective surface is harder to work on. Aluminized mylar should work very well, but the problems working with it are hard to solve, and it tends to oxidize pretty quickly, losing its effectiveness. White paint reflects a lot of the light, but it is diffuse reflection, so you aren't reflecting the light in the direction you think you are. If I were to try such a project again I think I would get a piece of round aluminum rain gutter and polish it as well as I could, then coat the polished surface with sprayed lacquer, so it wouldn't immediately oxidize.

You can also use strips of glass mirror glued to a properly shaped backing. Glass mirrors aren't as good a reflector as polished aluminum unless you use front surface mirrors, which are expensive. But, glass mirrors do reflect in the direction you want them to. I haven't tried this, but some have, and have reported their efforts here.

All of this is only my opinion, of course.


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## Glouglou (Feb 21, 2006)

*The best refletor*

The best material for DIY reflector is the famous Miro Silver with 98% reflective, if you need some contact me.


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## Gomer (Feb 2, 2004)

Here is something I wrote up a while ago that should serve you well.

Aquarium Plants - Info Pages


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## jorgeimbacuan (May 31, 2006)

Thanks to all for answers.

The material used for this project, may be stainless steel (it's cheaper than aluminium, and very resistant to corrosion).
Glouglou, what is Miro Silver?

I am looking for a *good shape *for a reflector. I know that a brilliant surface is not sufficient. Many hobbists use a section of PVC pipe
Many hobbists use a section of PVC pipe, they covered with aluminum, obtaining a very poor performance.

Some time I read something on a workgroup that were developing a mathematically correct curve, for a homemade reflector. But never I knew their final work.


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## Gomer (Feb 2, 2004)

Jorge, check my link if you haven't (posted above your post). It has mathematically correct "curves" for a homemade reflector.

Miro Silver is just a highly polished aluminum surface. It is almost like a mirror.


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## Glouglou (Feb 21, 2006)

*Miro*

Miro is the best reflector available to public around.

This is a German process where highly polished pure aluminium is recover with an special optical layer.

Normal anodised aluminum lighting grades have a total reflectivity of up to 87%.

MIRO SILVER has a total reflectivity of 98%. 
This is use in Flat Screen TVs , Computer Screens , Notebook Computers , Cellphones and PDAs.
A second equally important application is the use of MIRO-Silver in lightpipes and light directing building panels. It delivers high efficiency with little transmission loss- but also stays completely white with no colour spectrum shift - even after numerous reflections. It is also extremely durable and will not fade or lose reflectivity. excellent UV-C photo-stability and resistance to corrosion and extreme temperatures.


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## jorgeimbacuan (May 31, 2006)

It is perfect!!!!

I will read it tonigth.

Thank you!


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## hoppycalif (Apr 7, 2005)

Gomer said:


> Jorge, check my link if you haven't (posted above your post). It has mathematically correct "curves" for a homemade reflector.


Tony, that is the graphical method I used when I designed my reflector a couple of years ago. But, after I got it finished I realized it is a mistake to assume the light rays come out normal to the surface of the bulb. The inside of the glass is coated with phosphors, which do the actual light emitting. Thus, the light rays leave the bulb in a diffuse manner, in all directions. You can see this by looking at a lit fluorescent bulb - you see all surfaces as being about the same brightness, even though only the portion of the bulb surface directly in line with your eye would be bright if the light could be approximated as coming out normal to the bulb surface. I have been thinking about this, looking for a shortcut method of approximating the real bulb - a surface emitter, not a line emitter. Any ideas?

Edit: I did a rough ray tracing for a bulb with light emission from the inside surface. The shape should be very much like your example, but I think if the angles were calculated it would be a bit different - enough to make a difference.


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## Glouglou (Feb 21, 2006)

*Angles of reflection*

Well on any specular surface like Miro the incoming angle become the outgoing angle. incoming 30 degrees, outgoing 30 degrees (this is not true with other type of reflector). Hoppycalf the way you calculating your output is the same that I use. 
You say that light coming out of neon come out in a diffuse maneer, that make a lot of sense...
Well, I think that whith the diagram you make you got a very good approximation of the efficiency of the reflector and the most important the recuparation of the light coming out of the upper part of the light that is redirect toward the surface of the water. I believe that you can make a kind of focus point and with a good diagram of the number of light, the space between them, the height from the surface and the size of the tank, you should be able to maximise light output with this method.

A good reflector can add 40% more light to a setup.

Let the light beam on us...


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## Gomer (Feb 2, 2004)

well, if you want to do it right, you'd treat the entire surface as a point source.


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## hoppycalif (Apr 7, 2005)

Unfortunately, my desire to do something right often collides with my lack of ability or lack of sufficient incentive to do so! I'm thinking that one could estimate the size of each reflector flat, make a mirror that size and just play around with it to see how well you can see the back half of the bulb with it. Then, add the next flat, etc. You wouldn't need a full length of the bulb set of mirrors, just short ones to determine the best angles by eyeballing it. Once the complete set of 3 per side of the bulb is propped at the selected angles, you should be able to see the back and sides of the bulb from any spot that corresponds to an in-tank location. If nothing else, this would be fun to do.


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## mulligan (Dec 30, 2006)

I just figured AH Supply reflectors probably had the right engineering built into them. So I drew an end view on autocad and then scaled it up using the difference in radius between the compact flash they use and a t-8 bulb as the scale factor.


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## hoppycalif (Apr 7, 2005)

Because the light from a fluorescent bulb actually comes from the layer of phosphors on the inside surface of the bulb envelope, that light is very similar to that from a line source at every point on the bulb's periphery. It deviates from being a line source at some angle from a right angle to the surface of the bulb at that position, because the glass envelope will reflect the light back into the bulb at a small enough angle. This is leading me to want to find a way to bury the bulb far enough into the reflector so a minimum of the "sideways" light goes into the tank - that light illluminates the tank glass instead of the plants. I haven't figured out just how such a reflector would look, unless it is just a deeper version of an AH Supply reflector. I tried doing a crude ray tracing to figure it out, but ended up trashing it because I realized that no single tube light would be bright enough in any case, so this would have to be a multiple tube ray tracing. Sorry, I'm just doing some "free form" thinking here.


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