Sun Tunnel

Introduction: Sun Tunnel

About: I'm the illest. Please believe me.

Hi gals and guys! In this write up I will be showing you how I made a sun tunnel for my hydroponic plant. A sun tunnel is basically a tube that has a reflective interior and uses it through an opening at the top and bottom to bounce light and direct it where you want it. It’s commercial use is for homes that want to light rooms without having to waste energy. My intention is to use it to light up a hydroponic enclosure I have set up for a habanero plant.


Big plastic bottles like 2 litter soda bottles or larger.
Rustoleum Mirror Paint in Silver
Aluminum tape
Gorilla Clear water proof tape
Goof Off
Plastic Light Panel

Step 1: Prepping Bottles

So I did this write up before but to enter it into the lighting contest there be no use of internet images and instead of just changing the one picture I accidentally deleted everything :( lol. Anyways were going to want to use as many bottles as needed to be able to reach where we want the light to shine. In my particular case I needed 5 x 2.5 litter bottles of Shasta cola from the 99 cent store. I dumped out the soda in the sink, but I here its a good toilet cleaner so to minimize waste pour yourself a cold cup of some soda and dump the rest in the toilet, I didn’t want to spend the next few weeks waiting too drink the soda so I dumped it. Then were going to want to remove the labeling of the soda. Hardest part about this step is removing the glue sticky part section that is holding the labeling. I scraped off the really sticky parts with a razor, VERY CAREFULLY of course. I then used Goof Off to remove the remaining stickiness off the bottle.

Step 2: Cutting the Bottles

In the ideal situational use of these tubes they would be installed vertically, but I wanted to instal mine at an angle out of a window. I got a feel that when there’s angles involved with the use of sun tunnels, the light is reduced but I live in an apartment building so this was my only option. The opening of the tunnel that sticks out of the window has to point vertically to be able to collect the sun light and direct it where the tunnel exits. On the opening end I only cut the pouring tip of the bottle and placed gorilla water proof clear tape on it so no insects or water get inside the house i then used tape as a stencil of the section of the bottle that would leave a 45 degree angle portion unpainted leaving the opening I needed that would collect the light. I then cut 3 bottles at the top and bottoms to leave the straight sections of the tube that would be the majority of the length of the sun tunnel. And at the very bottom I could have done it as the top but because I’m going to use a light evening panel I cut at the bottom of the bottle and a 45 degree angled cut at the top of the bottle to direct the light down towards my plant. Again theoretically you can direct the light any where you want, thing of this as a periscope but for light, its just that I got the feel from what I read online that with the more angles and length used for your sun tunnel, the less light will travel through it. Also, if I could do this again I would cut the bottles as straight and clean as possible because that would help when tapping the bottles together.

Step 3: Painting the Bottles

Ok so this is the kicker. I was originally going to cut glass and make an elaborate glass sun tunnel, horrible idea. I cut my self pretty bad trying to do it this way, thankfully I was stopped the bleeding. Anyways I through everything in the garbage and almost scrapped the project all together but I kept going. I knew I couldn’t do it with glass mirrors anymore, I just wasn’t going to try it that way again. Then I came upon a video on youtube of a guy showing you how to make a mirror our of a picture frame by painting the glass with Rustoleum Mirror Effect spray paint. I thought that I might be able to get the same effect on plastic bottles and sure enough it works. So for this step I want to emphasize that you want to take your time. If you go thick on the paint it will drip and cause pin holes that the light will escape through and you will ultimately just be wasting paint. The paint is about $8 a bottle and I used 2-3 to paint 5 sections of soda bottles. So after you test fit all the bottles and your sure of your lengths and cuts its time to paint. So remember that for the section that sticks out I used painters tape to mask off the section that was going to be the “dome” and directs the sunlight down by the opening being positioned up. There are plenty of examples online I just cant post them here for copyright issues, so do a bit of research on top of reading this write up and your version will be 100 times better. Lite coats! Like 5-7 lite coats is what we want, pass the paint lightly once, and wait 15-20 minutes before the next coat. This is how you want to do it, its not about saving time but about saving paint and doing it right to get the best products possible. Don’t speed through it and you will be better off at the end. I unfortunately learned the hard way that because the bottles are standing vertically instead of laying flat, that when you go thick on the paint it begins to drip, and when you don’t wait long enough the paint builds up and drips as well. So in the end I had sections that there where pin hole openings and as a half a**ed solution I wrapped foil over those bottles to keep the light in. Remember take your time! And i should mention that we are painting the outside of the bottles. Ok next step.

Step 4:

Step 5: Light Panel

In my window set up that will probably be different with yours, I had a window that we installed an Air conditioner in and closed off the rest of the opening with wood. So I was able to use this window by drilling a hole in it to place by solar tunnel in. I also drilled a hole on the roof of my plant enclosure. I just wanted to mention that before the details of this step which are encompassed in the fact that when using reflective material to redirect light sun spots occur and create burn holes in plants. To tackle this problem I used light paneling that you can find at Home Depot. I cut the section I needed and screwed it on to cover and even out the sun light coming out of my tunnel.

Step 6: In Conclusion

All in all I think the project cost me about $35 using tools that I already had. Way cheaper than if I would have used a commercial version of a Sun Tunnel. This is a very hobbyist, diy version but I think it has plenty of room for improvement and I hope if you take on this project you do your own write up and tell us how you did it to improve upon this idea. Thanks gals and guys for your time, bye!

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    3 years ago

    Very clever idea, and a nice recycling Instructable.