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Thread: 48" parabolic mirror reflectors

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    RL7836's Avatar
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    48" parabolic mirror reflectors

    Has anyone come across any 48" parabolic mirror reflectors?

    Previously I invested time & $$$ into AHS outfits (which I liked alot) but found that the lamps burned out at erratic times (usually just after I left for a 3 day weekend). I'm probably going to be adding an additional rack of lights in the basement for more intermediate-highland growing space & would like to have the parabolic mirrors w/ T-8 lamps. If I'm unable to find these reflectors I may give in and try the T-5's since I continue to hear good things there - & I believe they have the reflectors...
    All the best,
    Ron
    You must do the thing you think you cannot do. --- Eleanor Roosevelt

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    Californian in DC DrWurm's Avatar
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    Ron,

    I don't know if the reflectors can be readily bought individually, but this is where I got my high bay T8 fixture: http://www.contractorlighting.com/hi...badffb7a2e7158

    It comes with lights and a built-in 95% reflector (make sure you order a three prong cord too).

    If you look elsewhere, go for the ones marked high bay. High bay lights are typically designed for high ceilings, and direct light downwards strongly. On the growrack this is desirable, as all your plants are located directly below the lights. You will minimize light waste this way.

    Jason

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    Tony Paroubek's Avatar
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    A parabolic reflector over 48" fluorescent tubes? I am not familiar with any other than the ones used with a HPS or MH bulb. There are some very good aftermarket reflectors you can get to place over fluorescent tubes but they are not parabolic. I would think that a parabolic reflector would only work well with a very bright point source light source. Perhaps we are thinking of different things?

    Tony
    Is that a Nepenthes in your pocket or you just happy to see me?

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    Californian in DC DrWurm's Avatar
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    Quote Originally Posted by Tony Paroubek View Post
    A parabolic reflector over 48" fluorescent tubes? I am not familiar with any other than the ones used with a HPS or MH bulb. There are some very good aftermarket reflectors you can get to place over fluorescent tubes but they are not parabolic. I would think that a parabolic reflector would only work well with a very bright point source light source. Perhaps we are thinking of different things?

    Tony
    Tony,

    The reflector that comes mounted to my light fixture is curved along the length of each individual bulb. I suppose that curvature function is described either spherically or parabolically, just not with the same parabolic function that is used in HPS and MH reflectors.

    Jason

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    Av8tor1's Avatar
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    Ron,

    Just for academic purposes, the "ideal" fluorescent lamp reflector design would be shaped like the McDonald's arch or the letter 'M"

    This would eliminate the deadzone inherit to a pure parabolic design. Parabolic designs work best when the area within the parabola is free of obstruction and the energy source being focused is external of the reflector.

    The double arch design greatly reduces this section of reflector that would normally be blocked by the bulb itself. However, from a marketing and manufacturing standpoint this design is not cost competitive.

    But if we reduce this area (with smaller diameter bulb) this inefficency is greatly decreased, hence the big advantage of the T5 format



    Av



    Butch

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    billylh's Avatar
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    hey Ron,

    I've had these sitting around here for a while. They originally came from 2'x2' troffer lights(ceiling grid fixtures) you put them side by side and you have the 2'x4' mirror reflectors. they are a little dusty but still very reflective. let me know if you're interested.





    ~billy

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    Californian in DC DrWurm's Avatar
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    Quote Originally Posted by Av8tor1 View Post
    Just for academic purposes, the "ideal" fluorescent lamp reflector design would be shaped like the McDonald's arch or the letter 'M"
    That's interesting. I might have to do some ray tracing for a double arch design. It doesn't seem like that would be much more expensive to create. Do you know how the normal parabolic reflectors are molded? Perhaps on a press?

    Jason

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    Av8tor1's Avatar
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    jason,

    I would imagine so, but most "quality" fluorescent reflectors are actually faceted, not true parabolic. I would think the problems with the double arch would be the design of the die used in production plus the resulting mounting issues. Both of which would result in a production cost increase.

    What is ideal is not always what is practical.
    Av

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