Mylar

[reefnewbie54321]

I was thinking about using mylar for my Lumenarc type reflector and I have a few questions.

Do you think it is as effective as polished aluminum?

"Mylar is a metalized plastic sheeting. It will reflect about 98% of the light that hits it." quote from some hydro store

"Space Age Reflector Agro Mylar Sheeting 1m x 1.4m 95-97% reflective" quote from hydro store

"Mylar is the most reflective material you can buy with over 95% of light been reflected back." another quote from a hydro store

<a href=showthread.php?s=&postid=7105043#post7105043 target=_blank>Originally posted</a> by calvin415
I was able to find this description from rplastics, the don't carry the metallized polyester but hopefully Mylar is Mylar...

MylarÃ"šÃ‚® polyester film or sheet is a flexible, exceptionally strong and durable film with properties that make it most suitable for many industrial applications. Mylar polyester sheet and film is inert to water and acts as a moisture barrier as well as being unaffected by oils, greases and most aromatics.

Even under attack by these conditions, MylarÃ"šÃ‚® polyester sheet or film will retain its superior properties and remain tough, clear and flexible from minus -100Ã"šÃ‚°F (-73.33Ã"šÃ‚° C) to over 300Ã"šÃ‚°F (148.88Ã"šÃ‚° C), and since MylarÃ"šÃ‚® polyester contains no plasticizers, it will not become brittle or yellow with age under these or other normal conditions.

I cant find the quote now but there was something on one of the sites that said mylar didnt have something calles plastizoids or something of that sort and therfore wont turn yellow or loose its reflectivity.

So far it looks pretty good,

-Dirt Cheap which is always nice
-90-98% reflectivity (there are alos different qualities of mylar and different thicknesses wich provide different effectivness so I will be on the look out of the "best of the best")
-Can take the heat
-Suposivly last a long time and should turn yellow or loose it reflectivity with age (need to research this aspect a bit more)

BUT

with all good thing there are always some concerns,

-mylar wasnt made for this purpose and I suspect its life expectancy wont be to long and since no one realy uses this for reflectives I dont if this is going to be true or not
-dont know how I am going to glue this to the reflector, I dont think I will even be able to use glue at all. Maybe thumbtacks or rivets and such.

All input would be appreciated, and anyone who has experience with using mylar as a reflective material would be even more helpful. As far as im concerned polished aluminum is better but by how much a meer 5% more efficent. Im not shelling out 45$ for a sheet of aluminum when I can get a roll of this for 15$ if theres only a 5% difference.

And most importantly with all DIY projects you usualy dont get good at it till the 2 or 3rd time around. With a whole roll of this stuff I bet I could pump out 6 of these and keep the best 2 and still make it for dirt cheap. Maybe even trade the others for frags and such.

 

[BeanAnimal]

There is a lot to cover...

firstly the mylar may be highly reflective, but you will not be able to get it flat enough to matter. Secondly, DIY reflectors are a waste of time (for the most part). You simply can not achieve the same focus and engineering that a well designed reflector does. Reflectors (good ones) are highly engineered pieces of equipment that provide the most light to the desired focus area, with the leat amount of reflections and scattering. This is something you simply can't even come close to achieving by eyeballing it.

Bean

 

[dvanacker]

Mylar is highly reflective stuff.......Most of our good relectors and coral growing hardware comes from the agricultural and hydroponic industry. They usually pioneer the technology and then we kinda tweak it abit for our aquarium purposes.

So my bet is mylar is probably a good product. I have seen the stuff before and I think if I DIY a reflector I would try gluing this stuff down.

 

[reefnewbie54321]

Well I have a copy of an AutoCAD BluePrints for the "Lumenarc Reflector" that got deleted from the DIY forum for legal reasons that had to do with patent issues ect. so I'm pretty sure this DIY reflector was designed pretty well.

If I were to glue it down do you think it would take the heat? and if it were to take the heat do you think the glue might be flamable?

EDIT: anyone have any suggestions on what glue product I should use?

 

[BeanAnimal]

The mylar is a very poor choice. As I stated you will never get it smooth enough to be efficient. You will have better results with white paint than you will with the mylar. Why not just use specular aluminum or the material the original "diy" project used (sola tube extension material).

Better yet, why not just buy the fixture, they are dirt cheap at the websites that sell siezed drug dealers equipment.

Bean

 

[reefnewbie54321]

I have experience with grow light fixtures, there poorley made and not fit for an aquarium. Grow rooms that are using these fixtures are plastered with mylar and dont depend on the effeicincy of a reflector.

I also have experience with mylar and I see no probelms with it. I have glued mylar down plenty of times and have never had any problems with it wrinkling on me.

A roll of mylars $15 and I have 3 4x8 sheets of aluminum flashing in my garage. Box of rivits is $5 so all together I have a cost of $20. A 30x30 sheets makes one reflector so thats enough materials to make 24 and with the scraps I could probably throw together another 6. All I want is 2 so that gives me 28 practice reflectors, I'm sure I will get the hang of it by then

 

[Maxxumless]

Iââ"šÂ¬Ã¢"žÂ¢ve had it in my hood for about a year now and I simply canââ"šÂ¬Ã¢"žÂ¢t find one thing bad about it. I used spray adhesive (3M I believe ââ"šÂ¬Ã¢â‚¬Å“ its been a while), it didnââ"šÂ¬Ã¢"žÂ¢t go on smooth as silk but I used normal reflectors screwed right on top of it. Therefore, Iââ"šÂ¬Ã¢"žÂ¢m losing nothing by having it there. There is a significant difference in light intensity. Itââ"šÂ¬Ã¢"žÂ¢s more than obvious. Most people that down it probably never tried it or implemented it wrong. Iââ"šÂ¬Ã¢"žÂ¢ve never cleaned it as my hood is pretty big and I donââ"šÂ¬Ã¢"žÂ¢t have any splashing on the surface. I have three 65W and one 96W PCs in the tank and everyone that has seen it swears I use MHââ"šÂ¬Ã¢"žÂ¢s or T5ââ"šÂ¬Ã¢"žÂ¢s ââ"šÂ¬Ã¢â‚¬Å“ its just that bright.

 

[BeanAnimal]

With all due respect, your experience with mylar is not in a direct radiating reflector where efficiency is the entire reason for it's design. Lining the walls of a greenhouse provides the "lost" light a way to get back to the plants, as well allowing the otherwise shadowed plants and leaves to receive some light.

You asked for help or opinions, yet you seem to not want to hear the replies unless they coincide with your plans.

There is simply NO WAY that you can get the mylar flat enough to be as efficient as a piece of rolled sheet metal. It may look flat and shiny, but it is far from flat. Every light ray that bounces off at a slightly incorrect angle will have to be reflected more than the intended number of times to get to the surface of the water. The loss in efficiency is tremendous.

This bring is back to DIY reflectors... even slight variations make a HUGE difference. Unless the "DIY" plans are exact, with little or no variance to the original engineered (assuming it was designed on a computer) reflector, and your fabrication skills can keep these tolernaces, your wasting your time and money.

Let me make this clear. Lets say the "original" is 95% efficient. Lets say becuase of errors in the "blueprints" the DIY design is 90% efficient. Lets then assume that your project is slightly different than the ORIGINAL and the COPY, but lets say you do a good job. So now we are at 85% efficiency. Add your Mylar and it's problems, your down to say 80% efficiency. In reality using a PAR memter your DIY model with MYLAR will likely be somewhere at least 75% as efficient as the origianl. If your trying to eeek every photon out of your light source this is very poor investment. If you could care less and just want to DIY, then there is no problem.

Again direct radiating reflectors are very highly engineered surfaces. Every angle is important, bulb placement is important. A bulb radiates in all direction. The idea is to get that light to the desired focus area with as few bounces as possible. Every surface imperfection severeley degrades the performance of the reflector. Mylar will create a very substantial surface problem, thus driving the efficiency of the reflector way down.

You mention "getting the hang of it". It is not really a matter of the your skillset, it is a matter of the design tolernaces and your chosen materials. If you just want to DIY something, then have a blast... the project will be rewarding even if it is not as good as the real thing.

Maxxum.... you are augmenting your reflectors by allowing light that bounces off the water surface to possibly be reflected back to the tank... of course this can not hurt and you may have increased your overall PAR and light spread. This is a lot different than trying to use the material is a primary direct reflector.

In the end you have simple decision to make. Is the significant loss in efficiency acceptable for this DIY project or do you need all the light you can get.

 

[dvanacker]

I do agree......it would be next to impossible to DIY a reflector that is as effiecent as the original.

Every little ripple, bend or cut would have to be perfect which is impossible.

 

[olemos]

<a href=showthread.php?s=&postid=7136207#post7136207 target=_blank>Originally posted</a> by dvanacker
I do agree......it would be next to impossible to DIY a reflector that is as effiecent as the original.

I have to disagree, the choice of material may be a problem but not the shape, if you have the rite dimensions, there is a total of 9 pieces and if they are cut rite, there is only ONE possible way that they fit together, so if they fit together, it has to be of equal shape as the original.

 

[olemos]

Beananimal, on Sanjays tests, he not only shows, but also states that a white painted surface is a bad choice.

 

[laramieh]

Unsupported Claims

Unsupported Claims

Can we see some light measurements to support the claims that DIY reflectors are not as efficient? It seems to me that if the mylar was close to flat the tiny imperfections would merely cancel each other out.

 

[BeanAnimal]

<a href=showthread.php?s=&postid=7136854#post7136854 target=_blank>Originally posted</a> by olemos
I have to disagree, the choice of material may be a problem but not the shape, if you have the rite dimensions, there is a total of 9 pieces and if they are cut rite, there is only ONE possible way that they fit together, so if they fit together, it has to be of equal shape as the original.

With respect, I don't think you understand how a reflector works with regards to efficiency. Yes you can measure the pieces, but even a slight variation will result in a totaly different focuc. Bulb placement is as important. Honestly, if you do not undertstand that, then this conversation is pointless. I agree that if you could exactly match the shape then your only viariable would be the reflective surface and bulb position... Like I said, a "copy" of a "copy" is not likely going to be anywhere near "exact".

Bean

 

[BeanAnimal]

<a href=showthread.php?s=&postid=7136870#post7136870 target=_blank>Originally posted</a> by olemos
Beananimal, on Sanjays tests, he not only shows, but also states that a white painted surface is a bad choice.

EXACTLY! And my point was the using mylar is as bad.

 

[BeanAnimal]

Re: Unsupported Claims

Re: Unsupported Claims

<a href=showthread.php?s=&postid=7137829#post7137829 target=_blank>Originally posted</a> by laramieh
Can we see some light measurements to support the claims that DIY reflectors are not as efficient? It seems to me that if the mylar was close to flat the tiny imperfections would merely cancel each other out.

There is no need for measurments. If you ask this, then you don't understand how these things work. Light and reflections are a very deginite physical science. With enough math, or a computer, you could easily design a reflector and then bend it or form it using the appropriate method. This is a far cry from slapping some mylar in a DIY box and calling it a reflector, no different than taking some glass and sandpaper and trying to fashion a lens.

"I made a lens a DIY NIKON lens" would be a very parallel arguement.

 

[olemos]

<a href=showthread.php?s=&postid=7137873#post7137873 target=_blank>Originally posted</a> by BeanAnimal
With respect, I don't think you understand how a reflector works with regards to efficiency. Yes you can measure the pieces, but even a slight variation will result in a totaly different focuc. Bulb placement is as important. Honestly, if you do not undertstand that, then this conversation is pointless. I agree that if you could exactly match the shape then your only viariable would be the reflective surface and bulb position... Like I said, a "copy" of a "copy" is not likely going to be anywhere near "exact".

Bean

Ok,If we go buy that, then it is almost impossible, even on a reflector that you buy, because it come with a lamp holder that you have to put in place and adjust ( you mite not put it in the same position that the technicians did when they did the calculations), bulbs from different manufactures have different lengths (if your not using the same bulb the technicians did for the calculations your not going to get the same results)
This is a DIY project it will never be the exact thing but I don't think the end results would be a significant difference.

 

[BeanAnimal]

I think the differences may be more significant than you think. Take the top three DE reflectors in sanjays tests. All three are fiarly hi-tech designs. Look at the differences in those alone. Are the real "luminarcs" they highly engineered? That I don't know. I just know that there is a lot more to a reflector than most people think. Like I said, if the DIY project is for fun and the realization is that the output may be significantly less than the OEM unit, then all is good. If the intent of the project is to build a better cheaper moustrap, then it is a waste of time.

Bean

 

[reefnewbie54321]

If your so agiant DIY projects why are you in a DIY forum?

Mylar isnt as efficient as polished aluminum but these tiny imperfections that your talking about arent gunna make that much of a difference. It will make a slight difference but its not enough to make me buy a sheet of polished aluminum. Have you ever even used Mylar? From what ive read you make it seem like this stuff is imposibble to get flat ... its not that hard.

 

[Maxxumless]

<a href=showthread.php?s=&postid=7138285#post7138285 target=_blank>Originally posted</a> by BeanAnimal
I think the differences may be more significant than you think. Take the top three DE reflectors in sanjays tests. All three are fiarly hi-tech designs. Look at the differences in those alone. Are the real "luminarcs" they highly engineered? That I don't know. I just know that there is a lot more to a reflector than most people think. Like I said, if the DIY project is for fun and the realization is that the output may be significantly less than the OEM unit, then all is good. If the intent of the project is to build a better cheaper moustrap, then it is a waste of time.

Bean

What type of tolerances are we talkââ"šÂ¬Ã¢"žÂ¢en about here Bean? I would say that 99% of the projects here do not measure within those set by professional engineers or the precision of multi-million dollar lathes and fabricators. This is a DIY forum and its not necessarily the aim of those here to be that critical of performance. Itââ"šÂ¬Ã¢"žÂ¢s the tweaking, testing, implementation and for me the cost savings that bring me to DIY.

On Beanââ"šÂ¬Ã¢"žÂ¢s side however, getting more than 90% of the light to ââ"šÂ¬Ã‹Å“stayââ"šÂ¬Ã¢"žÂ¢ in the tank is exceptionally hard and companies have designed very specialized reflectors to attain that. My route took both things into account by using a reflector then mylar to reduce lost light (mainly reflected back off the water). My hood is almost totally enclosed therefore I probably am reaching 98 or more percent efficiency. By implementing both methods I have attained what I know are tangible results (tested by a light meter in a plastic bag ).

 

[BeanAnimal]

<a href=showthread.php?s=&postid=7138681#post7138681 target=_blank>Originally posted</a> by reefnewbie54321
If your so agiant DIY projects why are you in a DIY forum?

Mylar isnt as efficient as polished aluminum but these tiny imperfections that your talking about arent gunna make that much of a difference. It will make a slight difference but its not enough to make me buy a sheet of polished aluminum. Have you ever even used Mylar? From what ive read you make it seem like this stuff is imposibble to get flat ... its not that hard.

I am not against DIY. You asked a question and I answered it with factual information. You either do not grasp the content or are unwilling to listen to it. The former being something I and others are willing to help with, the later being your right. A question was posed and good information has been given, do with it what you please.

I am not sure you understand what "flat" means in the contect we are talking about. If mylar is not as efficient as polished aluminum and a little more efficiency is lost because of the DIY surface imperfections.. then a whole lot of efficiency is lost. We are not even yet talking about the reflector design itself.

If you feel so strongly, then build the thing, buy or borow a PAR meter and test it against other meterials and the "real thing". I already know the answer, but you will then have your own proof.

Your right "It's not that hard", you just got the context wrong. It should not be that hard to understand why the Mylar is not a good choice.

My skimmer is DIY, as is my SUMP, my controller, my top-off system, my water change system, my light pulley system... I have tons of DIY. I design and etch my own circuit boards. I Brew beer, build my own audio amplifiers, build high end speaker systems, build wood projects and tons of other DIY stuff. I don't bother with reflectors, just as I don't try to build my own PUMP or lightbulb.

Bean