DIY diffusers for LEDs

Discussion in 'Do It Yourself (DIY)' started by EMeyer, Jan 11, 2019.

  1. EMeyer

    EMeyer Member

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    Many have complained about disco ball effects and hot spots with black box LEDs. Like many, I've experimented with using diffusers to reduce this. I'm not satisfied with how its gone and am wondering if anyone else has found a better solution.

    I've tried the plastic sheets sold at Home Depot for diffusing fluorescent fixtures. This gave about 30% reduction in PAR but produced a visibly more even spread without major hotspots. After turning them up to overcome the reduced PAR things looked good. It was promising enough to run them that way for nearly a year before finally admitting it was not helping. Many corals went downhill and grow was reduced overall.

    Plastic is optically not a good choice, since it absorbs some wavelengths more than glass and especially as it ages. My theory is that the plastic diffusers were making the spectrum worse for corals.

    I'd like to try a glass diffuser but cant find any easy materials for DIY. Privacy glass would be good, frosted glass might work too. Has anyone tried anything like this?
     
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  2. Kayden Hutchings

    Kayden Hutchings Active Member R2R Secret Santa Build Thread Contributor

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    Home Depot diffusers are not the most effective. I would get a piece of frosted acrylic and mount it about an inch or two away from the light.. the issues with frosted glass is mounting it. I see no way you could without a canopy.
     
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  3. dantimdad

    dantimdad Valuable Member R2R Supporter R2R Excellence Award R2R Secret Santa Build Thread Contributor North Alabama Reef Club

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    Working on a frosted glass mount.

    I wanted to try several different materials. When I get it down pat, I will post my steps to doing it.

    It will work for all materials if it pans out.
     
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  4. EMeyer

    EMeyer Member

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    I dont understand the difficulty with frosted glass. Why not just replace the glass panel of the black box directly with frosted glass? If I could find any that is what I would try.
     
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  5. dantimdad

    dantimdad Valuable Member R2R Supporter R2R Excellence Award R2R Secret Santa Build Thread Contributor North Alabama Reef Club

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    I thought about it. IMO, diffusers work better a little farther from the LEDs especially if you have lenses on them.

    I removed almost all the lenses on mine but still want about 1.5 to 2" from the actual bulbs.
     
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  6. EMeyer

    EMeyer Member

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    I've removed lenses from the LEDs on my shallow frag tank. It gives me maximal spread and minimal hotspots, and still has plenty of PAR to penetrate the ~6-8" of water in that tank.

    On deeper tanks, I've found that removing lenses makes it impossible to get decent PAR (>300).

    I have read that its ideal to put diffusers far from the light but its so impractical. If I can find frosted glass anywhere I'm gonna try replacing the clear glass with it.
     
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  7. dantimdad

    dantimdad Valuable Member R2R Supporter R2R Excellence Award R2R Secret Santa Build Thread Contributor North Alabama Reef Club

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    Actually, look at flippers 4 pups tank.

    He removed the lenses. Fantastic growth and PAR
     
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  8. redfishbluefish

    redfishbluefish Stay Positive, Stay Productive Staff Member Team R2R R2R Supporter R2R Excellence Award Build Thread Contributor Article Contributor NJRC Member

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    Why not try clear acrylic and use sandpaper to sand it. I'd start with 400 or 320 grit. If that doesn't give you enough "frosting", sand the other side.

    If you still wish to use glass, sandblasting with "frost" the glass.
     
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  9. dantimdad

    dantimdad Valuable Member R2R Supporter R2R Excellence Award R2R Secret Santa Build Thread Contributor North Alabama Reef Club

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    That's one of them I am trying. Just using several different grits on different pieces.
     
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  10. Saveafish

    Saveafish Well-Known Member Build Thread Contributor

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    No no no. Take all the lenses OFF. Than get egg crate. Don't use the frosted sheet panel. I did it. I'll post pics.
     
    Last edited: Jan 11, 2019
  11. Saveafish

    Saveafish Well-Known Member Build Thread Contributor

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    IMG_0076.JPG IMG_0075.JPG F IMG_0073.JPG Here.
     
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  12. dantimdad

    dantimdad Valuable Member R2R Supporter R2R Excellence Award R2R Secret Santa Build Thread Contributor North Alabama Reef Club

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    I'm not following how the eggcrate can help with hotspots and blending.

    Not arguing. I curious. I want to come up with the best solution for diffusing these things.
     
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  13. Saveafish

    Saveafish Well-Known Member Build Thread Contributor

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    This was my try and fails. With the lenses it made hot spots. Without lenses it was too wide of a spread. The egg crate seems to be in the middle. It was by accident I found it out. I used one to hold my light on my rack while I was tinkering and saw such a good spread. I was darn here we go. I'm loving it. I was also able to lower them closer to the tank as well.
    I'm thinking it defuses the light lower under the LEDs, causing a mixed spread.
     
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  14. dantimdad

    dantimdad Valuable Member R2R Supporter R2R Excellence Award R2R Secret Santa Build Thread Contributor North Alabama Reef Club

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    ok, well, if have eggcrate laying around, it won't hurt to try it too.

    So now, I have 6 different grits of sanded plexi, prismatic plastic and will add the eggcrate to the mix.

    Can't wait to get testing this.
     
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  15. Saveafish

    Saveafish Well-Known Member Build Thread Contributor

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    Yea test day.
     
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  16. Thingsibuild

    Thingsibuild Active Member

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    I'm wondering how it works also.
     
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  17. Saveafish

    Saveafish Well-Known Member Build Thread Contributor

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  18. Lingwendil

    Lingwendil Active Member Build Thread Contributor

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    Why not use the acrylic that is intended specifically for light diffusion?

    https://www.acrylite.co/acrylic-products/sheet/diffusion-grade-satin-ice.html

    I've used it on a handful of large scale installations, as well as smaller builds, it works very well, much better than the hardware store stuff. I like this stuff in particular the most-

    https://www.acrylite.co/satinice-optimum-light-diffusion-colorless-0d010-df.html

    With this one being a good option as well-

    https://www.acrylite.co/satinice-optimum-light-diffusion-wd852-df.html


    It works very well, but with any diffusion panel you need a few inches at least (six or more is better) between the emitters and the panel for good mixing.
     
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  19. Saveafish

    Saveafish Well-Known Member Build Thread Contributor

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    IMG_0077.PNG Here.
     
  20. Matt Carden

    Matt Carden Well-Known Member Partner Member 2019

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    I was planning on using eggcrate as a cover for jumping fish. The eggcrate would be 5-6 inches from the bottom of light. That would be nice if it also worked to diffuse my light.
     
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