PL-L refector shapes

[fatigues]

Awesome! Thanks for the search tip.... last time I did that, only pre-made kits came up.

This link

Is for a 24" x 48" sheet for $60!
You could make 6 reflectors out of that and still have working material so you're not saving every scrap.

Or you could just buy one for $15.99.

Given the modest savings, shipping costs and time to fabricate your own, I'm thinking "pre-made" is looking pretty good. The full 55w kit is looking even better, in terms of mounting hardware and "no second trips to the hardware store" factor.

 

[j6p]

^^ These AH Supply kits have Miro 4 reflectors which are sort of parabolic, without a "V" between the two tubes ...

I wonder if the extra space between the tubes and reflector would allow better cooling from the fan than the V configuration? Also, the AH reflector looks it might reflect a bit less than the V shape. It would be interesting to compare performance of the AH to the V, and see if there is much difference in light reflected downward and cooling.

 

[ricard0]

One more to the bunch

One more to the bunch

The AH kits are pretty nice. I'd speculate that the "V" reflector shape would probably throw more reflected light and reduce restrike. At least it appears that way on paper.

Here's my addition to the PLL club



Although for a slightly different application


I know, i know.... the MIRO material sux, but it'll have to do until i make my own with the help of this great thread

 

[Hydro-Soil]

I know, i know.... the MIRO material sux,

Yeah, turns out they don't reflect any UV

 

[ScrubNinja]

Yeah, turns out they don't reflect any UV

Hi hydro, why is that? Do they have a coating or something?

 

[Hydro-Soil]

Hi hydro, why is that? Do they have a coating or something?

Seems it was specifically designed not to reflect UV. UV is bad for business in the people area lighting business.

 

[D.I.trY]

thankyou so much for reviving this thread. nice work ricardo! regarding V shape, id agree that is the case on paper but also what i see with my eyes. I wonder, how would we mount those clips that ricardo has used on a V shape. This is what i couldn't brainstorm but my solution in my pc was to make a little hook shape out of some thick galvanised wire found in the gardenning section of my local diy store. I took a about a 10cm piece and bent it with pliars. I then had to fix this to the roof of the pc with a washer and a rivet. Not so clean but worked, so i had one end supported by the wired pins and at the other end, the U tip, by the bent wire.

thankyou for the really kind message you left me hydro. Its always a pleasure to contribute something for like-minded people.

 

[ricard0]

thankyou so much for reviving this thread. nice work ricardo! regarding V shape, id agree that is the case on paper but also what i see with my eyes. I wonder, how would we mount those clips that ricardo has used on a V shape.

Thanx for the kind words

After giving some thought to the idea you proposed, this is what i whipped out in a sketch to brainstorm the problem --->

Rough approximation of the current setup (from AH Supply in case anyone missed that)


If we use the metal clips that came with mine, we should be able to modify them to fit the reflector shape kinda like this, though the spacers won't work as is.


Thoughts??

Might also have to fabricate some custom clips if the standard ones don't work with the "V" shape reflector. Shouldn't be too hard for you metal fab'rs.

 

[D.I.trY]

Thoughts??

Might also have to fabricate some custom clips if the standard ones don't work with the "V" shape reflector. Shouldn't be too hard for you metal fab'rs.

Your sketches are great, seriously fantastic. Thanks for taking the time to draw them so carefully, scan them, and post etc. Its interesting to see how those ready made reflectors install the clips with those spacers, without having to buy one.

I dont have any clips to play with but we should be able to bend them into shape like your second sketch. The clips are really important because they hold the bulb securely and centraly to make sure the bulb is in the perfect place to maximise the V. In the way they are currently supported in my pc i gotta adjust them sometimes to make sure the bulbs stay centred.... im saying in my experience i think the clips are more important than is immediately obvious.

Im thinking these lights + a diy V shaped reflector would be awesome for other places in the house like undercabinet lighting in the kitchen, bathroom etc. to get a hell of a lot of light for your pennies... if one can be bothered. Incidently, those shitty 50W halogen spot lights may be all the craze for home lighting atm but they are always fuckign dying on me and are not cheap to replace!

Back on topic, that mount at the top made from wood ( best with triangular cross section i reckon to mount to ceiling) needn't be a long piece running along the reflector just small hand cut blocks where your clips will be and will attach both reflector and clips to ceiling. This is probably what you had in mind!

 

[ricard0]

It's the least i could do. You guys have obviously invested alot of time & work to get things this far.

As for the 1"x1" blocks, that's a great idea. I used some scrap strips of plywood to mount my lights to which ran the whole length. Using smaller blocks where they'd attach would remove some weight and make them easier to vent if one so chooses.

Also, if mounted to the blocks cut cross section as shown (isosceles right triangle), they remain flush with the top of the fixture allowing them to be modularized. Good for single strips on up

Hey, when you're finished crankin' out a few of the new design, throw us a bone and put a few on fleabay LMAO

 

[420ish]

i used vinyl gutter cut to 22 inches then mounted an outside corner bead for drywall in the middle and taped it in place with the aluminium tape and used same tape to cover the entire inside of gutter.i plan on cutting a slot in each corner bead and using a spacer under the clip to mount.when it is done i will post pics.i got the nice v from the corner bead and the gutter and corner bead cost me less then ten bucks.i already had the tape.that cost is for four reflectors

 

[Stumble]

Thank you all for this informative thread.

 

[knna]

Most materials used for reflectors dont refleck back UV, or just a little of near UV. Not only MIRO. But as far as I know, Alanod has some types of MIRO that reflects back UV at some wavebands (there is about 10 different types of MIRO).

I painted my DIY PLL's reflectors (exactly same design with tight double parabola) with heat resistant enamel with barite and yields improved a 15% since that. BTW, barite (Barium Sulphate) is very highly reflective (over 99%) but its reflect back on a lambertian pattern, that means that whatever the hood shape, some light is going to go again against the bulbs. Any diffuse reflective material will do. And barite reflectivity is very high from 430 to over 700nm, but under 430nm it absorbes way more light.

 

[fatigues]

I painted my DIY PLL's reflectors (exactly same design with tight double parabola) with heat resistant enamel with barite and yields improved a 15% since that.

knna,

If you can post a pic somewhere of your reflectors, or could post a DIY tutorial (even better) we would all appreciate that very much.

 

[WillyNilly]

Great info -much appreciated !!

 

[k1net1k]

I feel like people aren't making a big enough deal out of this.

Yeah even if these reflector exist, the fact he has done the testing explaining why it works is brilliant. I love how you can see what the plants are seeing. they see 2 extra half bright lights than they would normally get.

 

[vidro]

thanks for the reflector information

 

[marvil701]

Sorry for reviving this old thread, but making a new one wouldn't be justified just by looking at the useful information this one already has. This thread should be in the Growroom Lighting subforum.

Looking at the reflector shapes so far, it should be obvious that the M-shaped double parabola design is the way to go if you want the reflector to be almost perfect. The Adjust-A-Wings reflectors have the same shape for good reasons.
A user from the German hanfburg (= cannabis fortress) forum has used GeoGebra to design a reflector for PL-L tubes. He tried finding the ideal measurements, curvature and position by playing with various parameters of a parabola, something which programs like Mathematica would also be able to do automatically (it's called fitting functions). This is what his result looks like:
http://www.s14.directupload.net/file/d/3010/w8ce7ig7_png.htm
Which is very close to the Adjust-A-Wings design.

Unfortunately the curvature makes it very impractible in reality, at least if you wanted to construct it yourself, because shaping aluminium is next to impossible without the right tools. Of course you could create a mold out of wood and glue mylar onto it, but that's not a pretty solution either.

I guess what bakelite and DItrY have suggested on page 1 (the M-shape with out the curvature) would probably be a good compromise, although it would be nice to have a computer model verify which of those designs reflects the most light (while still being simple enough to construct easily).

Unfortunately I have no idea where to start when it comes to ray-tracing software (which would be great to find close-to-ideal shapes). Most software that I have come across so far is either very expensive (OSLO, Zemax, ...) or quite complex. Does anyone here have an idea how different designs could be easily tested (ideally using just the computer)? Any programs you guys could recommend?

Also, FYI: reflectors, especially for T8 and T5 (and also PL-L) tubes are also discussed a lot in aquaristic forums.

 

[marvil701]

I took matters into my own hands to get an almost perfect design:

http://imgur.com/PqHSiCt

The forum will only permit 150kb for a gif.

With this design next to none of the light is reflected back into the twin-tube. The only losses occur in between the tubes, but this can't really be helped and it doesn't matter that much anyway, because PL-Ls reach their greatest effifacy at 35°C, so some losses which convert to a rise in temperature are bareable.
It's quite a compact design at 10cm x 3.5cm and could be reduced in width by 1-2cm without losing too much light.

Unfortunately bending aluminium into this given shape is probably impossible in terms of DIY, so a simple approximation through polygon lines would be a sufficient substitute with most likely neglegible losses. In other words, cut a couple of 1-2cm wide aluminium stripes and arrange them as close to the parabolic curve as possible.

 

[ceylon]

hi marvil,
if u want some of these reflectors

and u'r active @hanfburg i can put some (how many u need) of them in the acm-auction@hb.

greetz ceylon