Myths about mirrors.

Ok. so this is my first post. ive been doing non stop research for the past 2 months about everything having to do with growing. everything from the lighting to the microorganisms in the dirt to the metabolism of plants. this is my first post so i want your opinions after i explain what i think about mirrors.

so first off i looked up things about light and how it reflects of surfaces. most people know about specular and diffuse reflection. white paint has a diffuse reflection while mylar and mirrors have specular reflection. this is due to the metal in the mylar and the mirror.

Everything i have found online about mirrors and growing is that everyone says they dont work cause it absorbs light. this is true in a sense. most mirrors are made of silver with a little tin mixed in to make it adhere to the glass. well guess what!!! silver reflects most of the visible spectrum BUT DOES NOT REFLECT MUCH OF THE BLUE SPECTRUM IN WHICH PLANTS USE
Check out this link. it is a graph of different metals and what they reflect
http://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Image-Metal-reflectance.png/350px-Image-Metal-reflectance.png

as you can see silver lacks the 200-400 nm which is all the blue and UVA that the plant needs. this makes mirrors unsuitable for growing, but more so in vegetative growth. it would work great for flowering as it reflects the orange and red as good as aluminum

which brings me to my next point. a lot of people do not know what mylar is made of. if you look into it you will find mylar is simply DuPont's name for its plastic that is attached to a vapor deposited layer of ALUMINIUM. which gives it a extreme polished surface which reflects light more specularly.

the fact is that aluminium itself reflects 98-99% of all visible light regardless of how polished it is. it also reflects infrared (heat) energy. this reflection of IR is what causes "hot spots" these are actually not caused by 1 flat reflection like a mirror but more by many tiny reflections of creased foil or mylar concentrating a large amount of IR into one spot.

I think (this is only a hypothesis) 2 things. 1) lining all your walls in pure aluminium based mirrors would be just as effective as properly stretched and mounted mylar and would actually be easier to work with. 2) mirrors would not create hot spots unless they are extremely close to the bulb and plant. simply put hotspots dont happen if ur plant is far enough away from the light source.

here is my next idea for a perfect reflector for hoticultural use. take aluminum tape and tape a wall up so that it is completely covered in a layer of reflective aluminum tape. then take flat/matte white paint and cover this layer of tape in a thin layer of this paint. the surface of white paint will make all light hitting it become diffused and all light that passes through the thin layer of paint gets reflected back at the paint by the layer of aluminium and continues to get difussed. Tell me what you think

You do know what a mirror is don't you? It's a piece of glass that has been covered on the back with aluminum. Glass has been proven to absorb light. If you are taking the glass component out of it, it isn't a mirror anymore, it is aluminum. Silver isn't used anymore to produce mirrors, so your theory already has a hole in it.

As far as covering walls in aluminum tape and then painting over them, you do know what a roll of that tape goes for don't you? Your idea has no pratical application or advantage over today's mylar.

Serapis said:

You do know what a mirror is don't you? It's a piece of glass that has been covered on the back with aluminum. Glass has been proven to absorb light. If you are taking the glass component out of it, it isn't a mirror anymore, it is aluminum. Silver isn't used anymore to produce mirrors, so your theory already has a hole in it.

As far as covering walls in aluminum tape and then painting over them, you do know what a roll of that tape goes for don't you? Your idea has no pratical application or advantage over today's mylar.

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Thank you.You poked the hole before i did.

OK now what about mirrors. what do you have about mirrors and reflection. if most mirrors are made of aluminum then what i said holds true. i have found no evidence that mirrors absorb more light then they reflect. mylar is simply a mirror then without the glass. i can see that very little light is lost from the transition of mediums but glass doesnt absorb or reflect light unless there is a high angle of attack of the light. so tell me or link me to a sight that explains how mirrors absorb light because the only evidence ive found is that silver mirrors would not reflect blue while aluminum mirrors would reflect nearly all light. here is a company makeing mirrors without the glass if that is the only problem with mirrors http://www.glasslessmirror.com/services.htm

and i know that aluminum tape is expensive i was mostly useing it as an example. more just trying to say covering aluminum in thin white paint would cause more reflection than plain white paint and more diffused reflection of the same light. that way even if you get many creases in your foil then the paint would diffuse the light.

A roll of tape goes for 8 bucks canadian for a small roll or 19 for a huge roll ---------> I used it in my current grow-------->https://www.rollitup.org/cfl-growing/359988-second-attempt-kalebs-2nd-grow.html

I had always wondered about mirrors, I thought they'd be great

I suggest you use a light meter and run some tests Godfather, perhaps you can prove the entire growing community wrong. You would still have to prove they are MORE effective than mylar or you are just wasting your time.

never meant to make it seem more effective then mylar. more like more available. mirrors work fine assumeing its an aluminum mirror. and i can see how if you have a 300sq ft grow room ur not gona go use mirrors. im talking for the closet grower who has access to mirror can line a grow room with mirrors and it will be just as effective if not more effective due to the fact that it is a perfect reflection. the only difference between mylar and mirrors is the glass. you will lose no more then 1% light from the glass. look it up it is lost through heat. im just saying that they do not absorb as much light as everyone just says withotu any knowledge to back it up, if you have a thousend feet to cover mylar is definatly going to be cheaper and easier. but mirrors are far more available and work just as good

mirrors break would have to be cut to size and would need to be washed near daily, if you can deal with that alone give it a shot man take pix and start a journal

mr.mike said:

mirrors break would have to be cut to size and would need to be washed near daily, if you can deal with that alone give it a shot man take pix and start a journal

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LOL, EXACTLY.... And how much weight are you hanging on the walls? anyone can go to eBay or Amazon.com and buy mylar. There is no sense in trying to reinvent the wheel.

Serapis said:

There is no sense in trying to reinvent the wheel.

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I gotta bust you on that statement Serapis.

The facts are already out there about everything we have for reflectivity, the hows and whys and what to use and there's always room for improvment.

Rock wheel----->Wood wheel----->Steel Wheel------>Rubber wheel

Without people experimenting things become static and advancement and growth don't happen.


Safe growing to you all and that's just a thought I had and take care


~Kaleb

I suggest you take a physics class dude, If you have.. Remember beers law? It states A=log I/Io where A= absorption I=Intensity after glass absorption and Io=intensity before glass absorption (intensity being light) Io will allows be a larger number because the light he's no substance to go through (ie. Air) once it hits the glass it slows down because of the difference in density between materials. Once it bounces off the reflective part of the glass, it looses more energy because of reflection.. But The remaining light will continue on to the plants.. Being I. The log graph shows even more energy you put in the system it will always decrease by the same amount...wasting money in lights and also those much needed electrons that the chlorophyll would love to absorb.

Cheers!

Dude, you forgot cheese wheel. The pinnacle of the evolution of thought.

Not that I would personally use mirrors, but just to play devils advocate....
If glass is so harmfully light absorbent why are cool tubes made of glass?

the glass that the cool tube uses is strong enough to withstand the heat that's generated by the gasses, anything else that would do that probably isn't clear. Since the bulb is the origin of the light, it's the strongest the light will be.. but after that, external glass would just absorb more light and why would you want to loose more light?

you also have to take into account the thickness of the glass, the thickness of the reflective material, the type of reflective material and what other energy is reflected other than light. Heat would be a big issue, especially in a small closet grow. but you would think the glass would act as a thermal barrier too. i know if you try to look through a window with a F.L.I.R. camera and its not calibrated proper, you wont see shit, a mirror would be 10x worse for the camera because of how much thermal energy it reflects. Think myth busters, when they fooled the I.R. motion sensor with the pane of glass...

Ok, I am glad for this discussion.
I have a few boxes of acrylic-mirror scrap that we use in the construction of the widget we build at work. It is anywhere from 16"X6" to 16"X2.5". I could do a 4-sided 6'X6'X8 easily.

It seems to me that a flat-on, single, big mirror would reflect at one angle. Not worth it. But what if I painted cardboard (free from work)white, and attached the scrap mirrors at odd angles with silicone adhesive, and used it to reflect up from the floor, or from the walls, etc. Multiple reflective surfaces at differing angles. To ultimately use and reflect the light, you would have to mount the mirror from the back of the cardboard, and have the acrylic mirror surface flush with the white cardboard screen. Like cut a hole in the cardboard and duct tape the sumbitch in place. Do it over a 4-foot section, and make a total of 4, and a fan and light.

If anyone thinks this acrylic mirror is not as reflective as glass, you are wrong. But the science of the wavelengths and shit, well, that's up to you.

I'm gonna do it. I make an offer on my first house this week!!!

Word.