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Mylar/Foylon vs Aluminum Foil *Title Fight*

Discussion in 'Indoor Growing' started by TeaTreeOil, Mar 27, 2009.

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    TeaTreeOil Well-Known Member

    Hello, how are you gentlemen? Doing well, I hope.

    I ask you to sit back, and consider the following.

    Mylar® is a trade name for a material from DuPont that consists of PET(polyester) fiber. Reflective Mylar® is made from aluminum deposit or technically is metallized and here to Mylar (polyester fiber).

    Foylon is foil laminated reflective material. Pretty much aluminum foil on fiber mesh. And is generally said to be superior to Mylar. Mostly for durability reasons.

    Aluminum foil is typically nearly pure aluminum.

    Aluminum foil is often claimed to have 50%, give or take 10%, reflectivity. Yet it is also claimed to create hot spots. This is counter-intuitive. IR light is treated similarly to visible light. They are both the same 'material'. Aluminum offers 95% IR reflectivity and 90% visible reflectivity. So if the 95% is enough to 'cook', the 90% is enough to grow! See: http://images.google.com/images?hl=...uminum reflectivity&um=1&ie=UTF-8&sa=N&tab=wi

    Yea, ®, you're paying for it, I'll include it!

    How does a supposedly poor reflector create hot spots?

    It just doesn't make sense. Why are the most suggested reflectors the same essential surface as aluminum foil? Aluminum itself!

    Think for yourself. :peace:

    PS. You may also want to look up the material safety sheets for Mylar. Apparently it supports combustion. Unlike aluminum foil.
    Brick Top

    Brick Top New Member

    Yet once again you are dishing out inaccurate information. Aluminum foil is made from aluminum alloy and not pure (99.9%) aluminum or nearly pure aluminum.

    Did you by chance happen to notice in the above that it clearly states that the aluminum used for aluminum foil is an alloy? An aluminum alloy is not pure (99.9% pure) aluminum or nearly pure aluminum.

    It may begin as pure (99.9%) aluminum but once it is combined with the other materials to make it into an alloy it is no longer pure (99.9%) aluminum or nearly pure aluminum.


    mindphuk Well-Known Member

    Of course you also are ignoring previous discussions (http://www.rollitup.org/grow-room-design-setup/168489-reflective-material-2.html) where it was pointed out that since foil is so thin, it is not able to conduct heat energy that it absorbs and re-radiates the small percent that it does which is why it makes such a good heat barrier. Of course thicker aluminum and foil bonded to other material can conduct heat and absorb more heat energy. Just like the experiment I mentioned by holding a piece of foil into an open flame vs. holding an aluminum bar the same 2 dimensional shape but thicker, you will drop the aluminum bar due to heat from conduction but will be able to hold the foil no problem because of lack of conduction (try it with aluminum flatware like a butter knife).

    You also are ignoring that aluminized polyester is still polyester and not a sheet of metal. It will retain much of the thermal properties of the polyester.
    Brick Top

    Brick Top New Member

    GrowRoom Reflectivity
    Choosing the right surface for the walls of your grow room is very important, as up to 40% of your total yield comes from the edge, and the right wall surface can increase the amount of light those plants receive by up to 30%! Artificial lighting diminishes exponentially with distance, so it is important to ‘contain’ as much of this light as possible, and direct it accordingly. Reflective surfaces also help illuminate the lower portions of the garden, providing lower buds with light and heat energy.

    To get the best results with your light and walls, it is important to get the walls as close as possible to your garden to ensure the least amount of light is wasted. As a caveat, the percentages provided are only useful as a general guideline, as they present the range of reflectivity of the particular surfaces. The high percentage presents the best possible circumstances for that material (for example a 99% reflectivity rating for mylar sheeting would be under ideal conditions - no creases, completely flat, no discoloration, etc).

    The best way to determine how well your grow room walls reflect light would be to purchase a light meter and measure your light directly; then take an opaque board and hold it a few inches off one of your walls with the light meter below the board in such a fashion that the light reflects off the wall and onto the light meter. You can then compare the difference between the two and determine a percentage from those numbers, the closer the two numbers are, the better your wall reflects light. It is important that in both measurements, your light meter is the same distance from the light, otherwise your results will be skewed.

    Also important to note is that radiant light energy refers to electromagnetic (EM) radiation with a wavelength between 400-700 nanometers (nm) and radiant heat energy correlates to EM radiation with a wavelength between 800-2000nm.

    Listed below are some of the most commonly used materials used for grow room walls:


    A more durable version of mylar, made of spun polyester fabric and reinforced with foil laminate. Foylon is resistant to most solutions, won't tear or fade, and can be wiped or washed clean.

    A great solution for growers who are interested in long term use, and though it may be slightly more expensive than mylar, its durability will more than make up for its cost. It has the ability to reflect about 95% of the light and approximately 85% of the heat energy, so a good ventilation system should be used in conjunction with folyon.

    A recommended method to attach Foylon to the walls would be using Velcro, as it makes taking it down for cleaning much easier nd reduces the risk of tearing, creasing or bending it. If this is used for your walls, making sure you get it flush with the wall with no pockets of air between it and the wall to prevent hotspots.


    A highly reflective polyester film that comes in varying thickness, the most common being 1 and 2 mm thick. The 2mm thick mylar while not quite as durable as the foylon, is fairly rugged. The 1mm thick mylar tears fairly easily, so taking it down for cleaning is quite difficult without damaging it in the process. Both types of mylar are able to reflect approximately 92-97% reflective, giving it the potential to be more reflective than foylon, but because foylon is more easily cleaned without damaging it as well as it being harder to crease, foylon usually ends up being slightly more reflective. Important to note is that mylar reflects radiant heat energy just as well as foylon (around 85%), so proper ventilation is necessary if mylar is used in your grow room. Attaching this to walls can be done in a similar fashion as foylon, and the same caution should be used to avoid creating hotspots in your room. The 1mm thick mylar stands a fair chance of being creased or ripped in the process unfortunately, even if Velcro is used to attach to the walls.

    C3 anti-detection film: (I'd sleep better at night if I had this.)

    A specialized type of mylar that exhibits the same properties as the 2mm thick mylar, but in addition to reflecting approximately 92-97% of the light, it also is 90% infrared proof, making your grow room all but invisible to IR scanning. This can also be attached in the same manner as foylon or mylar, and the same caution should be used to avoid creating hotspots in your room.

    Flat white paint:

    Self explanatory; a great option for large grow rooms or for people who are interested in a low maintenance wall. Flat white paint has the ability to reflect between 75-85% of the light, and does not create hotspots. Adding a fungicide is recommended when painting.

    Glossy and eggshell whites not reflect light as efficiently as flat white. Semi-gloss paint for example, only has the ability to reflect between 55-60% of the light. Also important to remember when using paint is that any smears or blemishes on the surface take away from how reflective the wall is so care should be taken to avoid marking or staining the walls. Titanium white paint is very reflective; however it is usually only used on reflectors due to its high cost.

    White/Black plastic (also known as panda plastic or "poly"):

    "Poly" is useful if you are setting up a temporary grow room or don’t want to damage the walls. Poly is easily cleaned.

    The purpose of the black side is to not allow any light to pass through the plastic, which ensures your dark cycle remains dark. The white side is 75-90% reflective. Choose a 6 "mill" thickness of poly for maximum light blockage and duribility.

    If this plastic is put too close to the light, you will obviously melt it so be careful!. Panda plastic does not create hotspots. Poly can be attached to the walls by using carpenter’s nails or using tape glue or similar means. This can be used as a cheap alternative to mylar if painting your grow room is out of the question.

    Polystyrene Foam Sheeting (more commonly known as Styrofoam):

    This is excellent for harsh environment growrooms (your attic for example), provided you have a good ventilation system and a way to keep the temperatures from rising too high (an a/c unit or similar) as it is an excellent insulator.

    It is also a great material for use in a temporary setup or for use as a "travelling reflector" on a light mover, where weight is a concern. It is approximately 75-85% light reflective so it is comparable to using a flat white paint. Foam will not create hot spots. Rigid foam can be purchased in sheets, and can be used as a free standing wall or can be taped, glued or nailed to the wall, the last generally being the most successful method.

    [​IMG]Emergency Blankets:

    These are ultra thin polyester blankets that are sold in most camping stores and are constructed of a single layer of polyester film that is covered with a layer of vapor deposited aluminum.

    It is not very effective at reflecting light because it is so thin. Holding it between you and a light source, many small holes are noticed at the intersections of creases and the entire blanket is translucent to begin with, this coupled with the many creases that are in it when you purchase it takes away a significant amount of it reflectivity. It is very easily creased as well which also detracts from its ability to reflect light. And while it is reflects nearly 90% of radiant heat energy, it is only able to reflect around 70% of the light.

    The largest advantage of using this type of material is that it is very cheap and therefore easily replaced. Emergency blankets can create hotspots if not attached flush to the wall so it is important that no air gaps exist between it and your supporting wall. The easiest way to attach this is to use tape (Aluminum or metal tape is recommended), as it tears very easily once it is cut or punctured.

    Aluminum Foil:

    Aluminum foil is no more than 55% reflective - if used, make sure that the dull side is the one that is used to reflect the light. When it becomes creased its reflectivity is even lower (around 35%.) It is also very dangerous to use because it creates hotspots easily, is electrically conductive, and is a fire hazard when it is in close contact with HID lighting. Attaching this to walls is a pain and usually using aluminum tape or glue is the best way. This should only be used as a last resort, and even then its usefulness is questionable.

    TeaTreeOil Well-Known Member

    Here's a chart I composited, It compares Al(aluminum), Au(gold), Ag(silver), Reflective Mylar®(red-dotted line), and ESR(Enhanced Specular Reflector Film blue-dotted line). 400-700 nm is PAR, the rest of the chart isn't as significant. But it is important to note, apparently, aluminum is aluminum. Also, Reflective Mylar® conforms to the curve of an aluminum mirror.

    They're both around 90-91% in this narrow region.

    Yes, aluminum foil is made from an alloy, so are most hood reflectors. Aluminum foil is made from an aluminum alloy which contains between 92 and 99 percent aluminum.

    Mylar® can hold a charge, and may support flame(combustion). Aluminum foil self-extinguishes. This makes me think nearly pure aluminum foil is safer.

    You can find the safety sheets on Reflective Mylar® here: http://www.dupontteijinfilms.com/

    According to 'Ask a Scientist' which side of the foil is of little significance. Though one notes the dull side isn't specular, which is pretty important for intense(low loss) reflection. Be warned, the discussion spans all 3 forms of heat transfer. It may be confusing.

    Foylon vs foil. We're actually comparing foil with foil at this point. :lol:


    Attached Files:

    Brick Top

    Brick Top New Member

    What most light hoods are made of is not the point, the point is what high quality light hoods are made of and that are made of pure (99.9%) aluminum that is pebbled or textured and highly polished and has a reflective coating applied to it.

    You have on numerous occasions tried to claim that the reflective capability of aluminum foil is the same as or very closely matches the high quality aluminum reflective hoods when that is so far beyond just being absurd that it is indescribable.

    If what you have claimed was true who in the world would spend a large sum of money on a quality reflective hood when they could just use cheap aluminum foil easily found in anyone’s kitchen?

    Why would you not read/hear people like Greenman and Jorge Cervantes in their videos and tapes saying ‘I use aluminum foil for my light hood and to cover the walls of my grow room’ instead of them telling about the high quality aluminum reflective hoods and Mylar they use?

    Do you honestly believe that you know more about growing than Greenman and Jorge Cervantes? Do you honestly believe that you have more experience growing than Greenman and Jorge Cervantes?

    People, if you have any brains at all don’t listen to the baloney the little clown shoe is feeding you about how good aluminum foil is and do like the true pros do instead.

    As for your links, well the first was Wiki so that can be considered to be less than credible. A professional author decided to test Wiki so he wrote a biography page about himself and in less than one year every single piece of information he had written about himself had been edited out and by others and was replaced with things that were untrue.

    Don’t trust Wiki or expect others to trust it either since it can be edited by people other than who provided the initial information.

    The next link was a link about Mylar so that proved nothing about aluminum foil.

    The next link supports what you claimed about the percentage of pure aluminum (99.9%) in aluminum foil but it does not jibe with other information that is on the web and in books so I do have to consider it to be dubious at best. It does not in any way go into any detail about how perfectly smooth aluminum foil quickly loses what little reflective capability it has with each crinkle and wrinkle and fold and taped tear etc. It also does not state that like quality reflective hoods aluminum foil has a reflective coating added to increase its reflectivity.

    The next link is a question and answer board, containing three entire questions and answers, about aluminum foil and talks about the heat reflectivity and conductivity of aluminum foil and while that may have some bearing in regards to heat transfer it is in no way validation of anything at all about aluminum foils reflectivity of light. The page talks about grilling hamburgers on a grill and storing food in a refrigerator and if it is better to have the shiny side or the dull side toward or away from different foods and why.

    The last link is about Vikuiti™ Enhanced Specular Reflector Film (ESR) which utilizes 3M multi-layer optical film technology to create a highly efficient, specular, reflector so that is hardly aluminum foil and if you believe it is aluminum foil just by chance I happen to own a bridge that connects a couple boroughs of New York, Brooklyn and Manhattan, and I would be willing to part with it for a very reasonable price.

    So of your five supporting links only one half credibly supports one single claim that you made and the rest are either not credible or meaningless or both in regards to actual aluminum foil.

    But as usual you have taken your typical W. C. Fields approach to try to make yourself appear to be knowledgeable and accurate.

    Your "if you can't dazzle them with brilliance, baffle them with bull" tactic won’t fool people who already know. The only ones you might fool are people who know even less than you do, which I pray there are not many of.

    TeaTreeOil Well-Known Member


    TeaTreeOil Well-Known Member

    It's up to 95-97%.

    You tell me.

    Paid product endorsement?

    Growing weed? Probably not. Properties of materials, yes, I would say I know more than them combined. It's a heavy area of study for CAD/3D artists.

    Aren't you just precious.

    So read the references. :roll:

    If you have time to bicker with me... you have time to read.

    It explains the post. You did read the post. Right?

    By whom? From where? You're all talk and no show. Boring!

    Radiant energy includes light. Both are radiant EM waves. The only difference is frequency and wave length.

    It explains the post. You did read the post. Right?

    It explains the post. You did read the post. Right?

    Aren't you just precious.

    TeaTreeOil Well-Known Member

    I have this to add:


    (yes, that's aluminum foil)

    Attached Files:


    mindphuk Well-Known Member

    what an absolute waste of bandwidth.:blsmoke:

    Was there an actual point to that?

    TeaTreeOil Well-Known Member

    The light temperature reflecting off the foil is within 97% of the bulb. Even at 7 feet away the foil is actually brighter than the bulb(as it's reflecting light upon itself from the wings).

    Just look at it, it looks like another bulb. It is clearly, broadly reflecting visible light. Not just IR. Though, this is why it can cause hot spots. It's an excellent reflector of both IR and visible light, just as reflective Mylar is. This makes sense. As they're both more or less bare aluminum surfaces(aluminum oxide coating naturally forms and protects the surface indefinitely when just exposed to air).
    Brick Top

    Brick Top New Member

    Your inaccurate beliefs have been shot down in flames several times here before by myself and also by others but for some inexplicable reason you persist in making inaccurate claims and handing out horrible advice to people who know even less than you do, which I find to be almost unfathomable, why do you do it?

    Do you really need me to tell you? It is because what you believe has been proven to be totally inaccurate by professional growers and by the use of facts that unequivocally refute what you so inaccurately claim time and time again. That is why intelligent people do not rely on aluminum foil for a reflective material and instead purchase much better products and professionally made reflective light hoods.


    TeaTreeOil Well-Known Member

    I think anyone who can manage Googling:

    aluminum foil radiant energy or click this: http://www.google.com/search?client...diant+energy&sourceid=opera&ie=utf-8&oe=utf-8

    Will easily find tens of thousands of sources which counter your 'single source' claims.

    Thousands of researchers, developers, scientists behind developing, manufacturing, and testing these materials... versus unknown online book.

    You're fucking kidding me!

    What do I hope to gain? Not having to read the same old bullshit ad nauseum, mostly.

    You do not shoot me down in flames. You keep changing your figures, and they're still wrong! You use the IR reflective numbers as the general indicator, and then use NIR(the same as a IR remote control!) values for the IR values. Keep your precious HoF award.

    I provided the graphs for bare aluminum versus Reflective Mylar. They're nearly identical. Bare aluminum is actually better due to the thickness.

    Apparently you lack the ability to process new information. I don't think you have anything more to add to this thread. *hint hint*

    PS. Grow up.

    TeaTreeOil Well-Known Member


    TeaTreeOil Well-Known Member


    mindphuk Well-Known Member

    Where do you get that from 25% less lux?

    Did you notice their painted reflector has higher reflectivity than some of their hammer finish and embossed aluminum reflectors?

    TeaTreeOil Well-Known Member

    160 watts total, 3000 lumen bulbs, versus 64 watts total, 2900 lumen bulbs.

    160 watts does 4% better than 64 watts. Just an example of how T8 is quite a bit better than T12, multiplied with a poor reflector.... Just awful. 2.5 times the power price for the same light(and more bulbs to buy!).

    The math is actually 129% over white, between the identical bulb comparisons. For the same electrical cost.

    That's significant. Think of it as... 3 bulbs without reflectors versus 4 bulbs without reflectors, to put it into concrete real-life terms.. but you pay the same price for electricity.

    Wouldn't you rather pay 75%, or rather have the same light intensity as paying 75% but pay 100%. Seems like a no-brainer!

    The Anolux Gold coating is minimally 72%, the white reflector is around 74% on average(lux). Plus, as the graph I have provided clearly shows, gold doesn't match up to silver or aluminum in visible light reflectivity. Gold would be alright for HPS or Warm White CFLs, but not MH or Daylight CFLs. Lots of wasted light below 500 nm wavelengths. But it has superior IR(heat) reflectivity, which could be bad.

    All the rest of the Anolux surfaces are minimally 84% or better. Or minimally 10% superior to the white reflector surface. The surface used(Anolux Miro IV) is minimally 25% superior, that's where they get their figure.

    Those Canadians at Anomet... emphasis not on the best, or averages, but the minimums. Interesting way to list their products. Never seen others promote their products this way! I like it.

    Notice as the diffuse % increases, reflectivity generally drops. Except where the surface is designed to do both, but image clarity disappears.

    TeaTreeOil Well-Known Member

    I posted this in another thread about IR barriers.


    It's even used in space to protect astronauts: http://www.radiantguard.com/reflective-foil-insulation.html


    http://www.insulation4less.com/ (they have a guy that explains it)


    Here's a direct comparison between a brand of Aluminum Foil and Reflective Mylar(metallized plastic films). http://www.troutcreektruss.com/Products/Rigid-Board-Comparison.pdf


    mindphuk Well-Known Member

    So instead of comparing the painted white reflector with the same bulb setup, where they point out 25% (actually 23%) less light, you chose to try to compare a 4 bulb T12 with a 2 bulb T8 and then assess that difference to the reflector? Your mental gymnastics somehow comes up with a "twice the lumens(or bulbs)" to surpass the better reflector, implying the reflector must be twice as efficient when it clearly is only 25%.

    TeaTreeOil Well-Known Member

    Yes, the reflector is minimally 25% better. I completely agree.

    256.7 - 199 = 57.7 lux difference

    57.7/199 = .2899

    So, the amount increased, compared to the original, is 29%, rounded, sorry if you don't like rounding.

    I say 29%, consider it how you like.

    I suppose if we go in the opposite direction we can conclude it is 33% greater, maximum.
    chronicj69 likes this.
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