Mylar

[BeanAnimal]

Nobody said that those "other" reflectors were good or that a DIY unit would not outperform a poorly made OEM unit.

Also rich, it's not the "cutting" tolernaces. It is the design itself. The shape of the reflector dictates the footprint (focus) of light that will be cast. I agree that open ended designes are leaving efficiency on the table.

As well as the "focus" the angle of each ray of light is important as well. Steep angles penetrate the water, and shallow angles bounce off. The shape of the reflector determines these angles.

The shape of the reflector also determines how many times a given light ray will bounce before it reaches it's target. Each bounce reduces the efficiency due to scatter.

The surface material dicates the amount of light the bounces (or is lost to scatter). This includes not only the actual choice of material, but also imperfections in the material. These would include bumbs, wrinkles, dents, waves... whatever.

Thicker mylar will lay flatter with less surface distortion. There however is a reason it is not used for primary reflectors, highly polished aluminum works better and is easier to maintain and fabricate.

Putting tinfoil above VHO lamps is better than having no reflector at all, this certainly does not make a tinfoil reflector good. It just makes it better than nothing.

If your contention is that his DIY unit will be better than poorly designed refector, then I would agree. I never disagreed.

Honestly, do you guys read the posts in the threads or just a few sentances and then shoot of on a tangent?

 

[RichConley]

Bean, I know all of the above.

This just reminds me of the the thread about penductors where you went over and over about how you'd never match an engineered design, and it turned out that most of the DIY eductors smoked the penductor, because the penductor was crap.

I do agree with you that mistakes will be magnified, IE an angle being off 5' means light reflection will be off 10'. My contention is I dont think that even the good reflectors are as highly engineered as you think. These are mass produced units.

Theres a reason the horticulture guys have mylar on their walls: these things arent that good. If they were, you'd have light on the ground, and plants, and thats it.

 

[BeanAnimal]

Rich... I never said the penductor was good. I said they were CHEAP for what they did. The meat of the discussion was about DIY eduction vs engineered eduction. Also, I surely don't remember ANYBODY showing thier DIY eductor was more efficient than any other eductor (Engineered or DIY).

Actually come to think of it, that discussion was fairly cordial except for the part where you and a few others went on the attack. Each time we tried to talk about the facts, somebody flew off on a tangent or personal attack... so yeah this reminds me of that thread as well. Hrmm You were there... and now your here!

Is your purpose here to discredit me? It sure looks like it. Talk about going out of your way to cause trouble.

The mylar on the walls helps to get all of the leaves some light... .even the ones that are shadowed by the overhead lights. Why let that light go out the window when you can get some of it on target.

With regards to the units available.. I would direct you to Sanjays website where some real world numbers can be compared.

 

[RichConley]

<a href=showthread.php?s=&postid=7149169#post7149169 target=_blank>Originally posted</a> by BeanAnimal

The mylar on the walls helps to get all of the leaves some light... .even the ones that are shadowed by the overhead lights. Why let that light go out the window when you can get some of it on target.

With regards to the units available.. I would direct you to Sanjays website where some real world numbers can be compared.

If the reflectors were great, none of the light would be reaching the walls. As to sanjay's site, its great, but it compares reflectors. It doesnt have a perfect output anywhere.

My point isnt to discredit you Bean, my point is that you always seem to assume that products ARE efficiently engineered, which to my experience, in this hobby, is completely innacurate. Every thread I have been involved in with you, you are always arguing for the manufacturer.

In regards to the eductor thread, plenty of people showed that theirs were much better than the penductor. Even had videos. You kept bringing up engineered eductors, but no one could find a well engineered one that would run on the pressure of an aquarium pump.

I'm not arguing that a well designed and engineered reflector wont destroy his DIY. What I'm arguing is that any of them are really that well engineered. The level of optimization you are talking about costs tons of money, and extremely fine tolerances for design. Making something 90% effective is cheap. Making it 97? really expensive.

Electricity is still relatively cheap. It just isnt worth it to spend millions to get 2 or 3 more percentage points. Also, optimizing these things to a reasonable level isnt that bad, you can do it in matlab.

If these things were fully optimized, or optimized to even a complex degree, there would be no facets in them. They would be all curves, and they would cost thousands.

 

[BeanAnimal]

I don't know where you keep getting the idea that the I feel there is an abundance of well engineered products in this hobby. I feel that 99.9% of the stuff is pure junk.

I feel that there are a LOT of areas that DIY can produce better or more efficient products or solutions. I don't feel that DIY venturis and reflectors are in that categorey. It's that simple.

YOU decided to hop and and mold my positon to fit your premise. You have changed the debate and attempted to show that I am wrong.

The fact is that the better reflectors available to this hobby will be much more efficient than the average guys DIY design with of all things, MYLAR, glued to it. THAT SIMPLE. Yet you and a few others here tant to twist this into something it's not. Even going as far as accusing me of being biased towards manufacturers, being wrong in other threads, and not supporting DIY.

The better OEM reflectors are cheap. In this case the LUMINARCS are available for less the $100 from the police auction sites. The NEW HOBBY SPECIFIC LUMINARCS will be available anyday for a MSRP of $149 from SLS.

SO LETS GO BACK TO SQUARE ONE. Build a DIY Luminarc and lose a few percent due to build differences. Toss in the MYLAR and lose a few more percent to surface problems and reflectivity issues. If you can live with 10-20% less PAR then go for it... if you need every photon you can get.. then your wasting your time.

Please go back and read that paragraph berfore you respond. That is and has been the entire point my position.




Nobody was able to measure the output of the eductors... we all agreed that it was subjective. Why do you insist on making that part of this discussion. Rich.. honestly can you just focus on the topic at hand.

 

[BeanAnimal]

<a href=showthread.php?s=&postid=7149538#post7149538 target=_blank>Originally posted</a> by RichConley
If the reflectors were great, none of the light would be reaching the walls. As to sanjay's site, its great, but it compares reflectors. It doesnt have a perfect output anywhere.

Let me say this again... the mylar on the walls is to help light get to the under leaves and areas that would otherwise be shadowed. A "perferct" reflector could not achieve this.

Yes Rich, it compares reflectors. Anybody with a small amount of sense can then compare the par or footprint of various reflectors to deterime the differences per application. In other words it is easy to tell which reflectors have a better design. If one wanted to measure their own reflector, Sanjays numbers could be used as a reference point.

 

[RichConley]

<a href=showthread.php?s=&postid=7149834#post7149834 target=_blank>Originally posted</a> by BeanAnimal
Let me say this again... the mylar on the walls is to help light get to the under leaves and areas that would otherwise be shadowed. A "perferct" reflector could not achieve this.

I understand that bean. The thing is, if the reflectors were designed to optimum efficiency, using mylar on the walls like that wouldnt be effective. It wouldnt work because there would be no light reaching the walls. It would be all going straight down. In our application, all that light is lost.

Yes Rich, it compares reflectors. Anybody with a small amount of sense can then compare the par or footprint of various reflectors to deterime the differences per application. In other words it is easy to tell which reflectors have a better design. If one wanted to measure their own reflector, Sanjays numbers could be used as a reference point.

yes, it tells you which reflectors are better than others, but there is no baseline. Its like comparing a honda civic, a ford focus and a toyota corolla, and concluding that the corolla is fast. Its not. Its just faster than the other two.

His pages are all relative. Theyre great if you're trying to pick between two reflectors, but not very useful if you're trying to create a new design.

When it comes down to it, an optimum design for us would be all light going straight down. Even luminarcs dont come close to that.

Also, any increase in faceting would improve that. For an optimum design, we'd end up with something looking like a sattelite dish. A 3D parabolic design.

As to the spectral aluminum vs mylar, the highest aluminum I have been able to find is 95-97%. And that stuff is EXPENSIVE. Way more expensive than the lumenarc, just in materials. The lumenarcs are probably using the 93-95% stuff that is reasonably priced. Mylar is in that same range, 90-95%.

You keep bringing it up that you wont get mylar completely flat, but I dont see that as an issue. (most mylar I've seen has sticky backing, so you dont need any glue, so its really easy to get on, and get flat.) A perfect reflector wouldnt be flat, it would be curved. Yeah, you'll lose a little light, but most of it will be still reflected generally down, which is about as good as you're going to get from the design anyways.


As to the venturis, many DIYers have tested with airflow meters, and for under $2, have made venturis that suck much more air than the Kent ones that you keep reccomending on the same pumps.

 

[rforrest3]

I still think people are missing the boat here. It is a DIY thread. If someone wants to save a little monay and build something that is better than nothing or an improvement of what they are using today, then great. I am here to try and find a better reflector than what I currently have. With that said mylar would be better than the open ended reflectors I am currently using. I may not be getting what the manufactured high end one does, but it will be better than what I have.

Bean, I have bit my tounge and not said anything when you are posting until now. I have read many of threads that you have posted to(I don't think I have seen one you haven't posted to) and you are always on the defensive. I am a peoson who comes here and reads but do not post much. It always seems that you are against any design someone comes up with. I'm glad you have the time and money to engineer things and get the best product out there by DIY. I just like to read what people are trying and improve apon that and use DIY designs.

Please help us all get the best for our organisms and move on.

I will leave it at that.

 

[BeanAnimal]

I understand that bean. The thing is, if the reflectors were designed to optimum efficiency , using mylar on the walls like that wouldnt be effective. It wouldnt work because there would be no light reaching the walls. It would be all going straight down. In our application, all that light is lost.

So what rich? This has nothing to do with the arguement at hand. Honestly, why can't you ever keep focus on something simple. With each post you spin further from the original point.

WE ARE TALKING ABOUT A DIY COPY OF THAT SAME REFLECTOR!!!!

Please try to focus (no pun) intened.

yes, it tells you which reflectors are better than others, but there is no baseline. Its like comparing a honda civic, a ford focus and a toyota corolla, and concluding that the corolla is fast. Its not. Its just faster than the other two.

Again so what rich... IT'S A BASELINE and perfectly relavant to our inteneded purpose. Again please try to focus. We are talking about a DIY LUMINARC vs the REAL THING. We are talking about A DIY LUMINARC with MYLAR.

His pages are all relative. Theyre great if you're trying to pick between two reflectors, but not very useful if you're trying to create a new design.

Here you go again.. spinning wildly off topic. Nobody said ANYTHING about a new design, other than that it takes a good bit of science and calculation. Please try to focus on the point. We are talking about a DIY LUMINARC vs the REAL DEAL.

When it comes down to it, an optimum design for us would be all light going straight down. Even luminarcs dont come close to that.

What makes you think so? Again WAY OFF TOPIC.. but this could not be further from the truth. The optimum reflector would focus light downard and at all angles less than the "critical" angle. This would create less shadown area... but this is a debate for another in depth thread.... THAT HAS NOTHING TO DO WITH THIS THREAD.

Also, any increase in faceting would improve that. For an optimum design, we'd end up with something looking like a sattelite dish. A 3D parabolic design.

We are not talking about an optimum design... we are talking about a LUMINARC and a DIY COPY.

As to the spectral aluminum vs mylar, the highest aluminum I have been able to find is 95-97%. And that stuff is EXPENSIVE. Way more expensive than the lumenarc, just in materials. The lumenarcs are probably using the 93-95% stuff that is reasonably priced. Mylar is in that same range, 90-95%.

And finally you touch on something relavant. If you bothered to read the thread, you would see that the "sola" tube material is available and rather cheap in some cases. If I remember it is a 98% material. 95% mylar will not end up being 95% efficient in terms of light placement. Again this has to do with it's surface properties and the fact that it can not be made to lay perfect. Also if you look into mylar you will notice that any it is easily damaged with microscopic fissures. These redice the reflectivity significantly. MYLAR is the substrate. It has a metal film, attached to it. The film is the delicate part.

You keep bringing it up that you wont get mylar completely flat, but I dont see that as an issue. (most mylar I've seen has sticky backing, so you dont need any glue, so its really easy to get on, and get flat.) A perfect reflector wouldnt be flat, it would be curved. Yeah, you'll lose a little light, but most of it will be still reflected generally down, which is about as good as you're going to get from the design anyways.

I don't know if I should laugh at this or respond. Rich from context you should have been able to deduct that "flat" was in reference to the surface conformation to the desired shape, not a "flat plane". Secondly, "genrally down" means nothing. If the light is not being reflected at an angle equal to, or greater than the critical angle, it will bounce off of the surface and be lost anyway.

Furthermore, since you keep talking about facets, curves and parabolas.... The reason we don't have "dish" shaped reflectors is simply due to size. Well placed facets can reduce the size of the curves and reflector. Bulb diameter and the shadow it casts are also a significant obstacle that must be designed around. These are issues that some of the better reflectors have worked around to some extent... something tht a DIY guys is not going to be able to do... UNLESS HE COPIES A DESIGN... and then Rich.. we are back to square one and the the fact that a COPY will not likely perform as well as the original.

As to the venturis, many DIYers have tested with airflow meters, and for under $2, have made venturis that suck much more air than the Kent ones that you keep reccomending on the same pumps.

Um Rich.. I never said the KENT was a good design. Again I stated that it is cheap and works well enough... please don't confuse me with others (FPPF comes to mind).

You may also want to note that many of those "DIY" venturis were not venturis at all. Instead they were placed in the inlet side of the pumps and driven by SUCTION from that pump. A simple hole with a piece of hose stuffed in it will do that. An angle at the end of the hose will help to prevent turbulance.

Why do you insist on trying to bring up old threads to prove your point? I certainly have not quoted anything you have spouted in the past and do not intend to. Please, keep this in context and stop grandstanding.

 

[BeanAnimal]

I still think people are missing the boat here. It is a DIY thread. If someone wants to save a little monay and build something that is better than nothing or an improvement of what they are using today, then great.

By all means I 100% agree. I have never disagree with this premise and have said so many times. You simply have chosen not to see that.

I am here to try and find a better reflector than what I currently have. With that said mylar would be better than the open ended reflectors I am currently using. I may not be getting what the manufactured high end one does, but it will be better than what I have.

A very valid problem and DIY is a possible solution. However, the point here was that the chosen design is readily available at a very small cost. The second point was that the MYLAR is likely waste of time if the unit is already being made from aluminum. I mentioned that the "sola" material was available and others had success with it.... as well as posted a link to some fairly inexpensive MYLAR anyway. Instead of moving on.. some people decided to argue and here we are. We have people bringing up old threads (YOU AND RICH). People arguing about stuff that was never said...

Bean, I have bit my tounge and not said anything when you are posting until now.

Bah.. you have posted twice my friend.. both times attacking me. So you must not be very good at bitting your tongue.

I have read many of threads that you have posted to(I don't think I have seen one you haven't posted to) and you are always on the defensive.

That is a load of BS. Sadly it is folks just like yourself who provoke this crap. Just look above at your first post, and then your "i bite my tongue" comment.

I am a peoson who comes here and reads but do not post much. It always seems that you are against any design someone comes up with.

Again that is nonsense. I contribute where I can, with what knoweldge I have. Folks like then stop in and start a fight becuae you feel differently. Sadly you seem to feel you hold the high ground becuse you are championing somebodies idea because you agree with it. Thats nonsense too. You somehow feel it gives YOU the right to moderate the thread or the answers? Instead of contributing something usefull, yuo just CANT BITE YOUR TONGUE and throw a few insults in. PLEASE GO READ BOTH OF YOUR CONTRIBUTION HERE AS AN EXAMPLE.

Sir, your worse then me. You came here to hurl mud, not help. My intentions were to discuss teh ideas, technology or science regarding this project.

I'm glad you have the time and money to engineer things and get the best product out there by DIY. I just like to read what people are trying and improve apon that and use DIY designs.

I never said I get eht best product by DIY. You made a sarcastic comment about my proejcts and DIY status.. I simply clarified my position.

Part of DIY is learning from others or trial and error. Did you forget that the OP asked a question here? Sadly he did not like the answer, even to the extent of creating a second user account to start a fight.... now that was kind of funny.

DIY can be very rewarding... I have said that all along. I think if you re-read this entire thread, you will find that A few of your have caused an arguement just for the sake of doing so.

Please help us all get the best for our organisms and move on.
I will leave it at that.

What in the world makes you think that your "Last word" means anything. Your the guy who has dragged this back into the mud twice. At least Rich has posted some good information. Honestly all you have done is cause trouble here.

Bean

 

[budhorse775]

wont mylar lose its reflection if it gets wet?

 

[MiddletonMark]

And it does seem to get permanently damaged IME from salt spray.

Personally, if looking to save a buck - I would just go on one of the California police auction sites and buy one off their drug-seizures.

Same reflector, way cheaper ...

But if you like to DIY ... DIY away

 

[BeanAnimal]

Reflective Mylar is made of a layer if MYLAR plastic coated on the back side with ALUMINUM (in most cases).

The Mylar fim protects the aluminum backing, so it is waterproof. It is cleaned very easily becuase it is plastic and does not tarnish.

 

[MiddletonMark]

And guys - let's avoid the personal slams at each other.

It doesn't advance either of your arguments, tends to make others shy away from joining the discussion ... and if kept up, will be addressed by more than a polite warning

And back to mylar ...

 

[BeanAnimal]

Never had it under salt spray... Mark does it deteriorate or do you think it is surface scratches or discoloration?

 

[RichConley]

<a href=showthread.php?s=&postid=7150753#post7150753 target=_blank>Originally posted</a> by MiddletonMark
And it does seem to get permanently damaged IME from salt spray.

Personally, if looking to save a buck - I would just go on one of the California police auction sites and buy one off their drug-seizures.

Same reflector, way cheaper ...

But if you like to DIY ... DIY away

The problem is, salt spray destroys aluminum too. SO thats not really a consideration.


Bean, chill out. You have to learn to not get so emotional about this stuff.

Your main contention here is that a copy of a design can not be as efficient as the original design. If the original design was perfect, I would agree, as any deviation would cause issues. The lumenarc design is not even close to perfect, and because of that, slight changes in design may not be to the detriment of the final product at all.

Facets, are not there to reduce space, or any crap like that. They are there to make the design easier to fabricate. No other reason. They make it a reasonable cost. Every time you increase the number of facets, you increase the efficiency of the reflector (its a optimization curve, ending with no facets, but a smooth curve)


For some of us Bean, there isnt much expendable income. $130 for a reflector isnt cheap. If he can put out something thats comparable for $30, then he should, because it will be much better than his old reflectors. If you have no constructive advice that is within the constraints of peoples needs/means, then please dont post.

 

[BeanAnimal]

Who said I had extra expendable income.... I expend it all.

Rich I agree with part of your reasoning for facets. However, the "smooth" curve is not as simple as it sounds because the bulb complicates the issue. I would also agree that it is easier to make 5 folds instead of a single parabolic curve, as the complex curve is hard to bend and hold.

Why can't you guys just post without saying stuff like "chill out"? It's so sad it's funny.

 

[rforrest3]

Bean, I sent you a PM to not distract from this thread any longer. Not trying to fight anymore and if you can show me the threads you say I attacked you I will post them here for others to see.

Lets be friends now.

 

[RichConley]

<a href=showthread.php?s=&postid=7150897#post7150897 target=_blank>Originally posted</a> by BeanAnimal
Why can't you guys just post without saying stuff like "chill out"? It's so sad it's funny.

Bean, I asked you to chill out because your last few posts have been very confrontational, and full of personal insults. Its so sad, its funny.

 

[BeanAnimal]

Re-reading my earlier post I also realize that the comment regarding "space" and "facets" was not wholey correct. I was thinking of sound waves, not direct geometric reflections.

FWIW a "horn" type of speaker design can be made smaller by folding the horn and/or reshaping the curve. Where the optimum design may have a throat of a few inches and a mouth as wide as 30', a comprise can be made in several areas to reduce the size of the horn to what you would see for sound reinforcement at a concert for example. Sadly light does not expand like a sound wave.. it reflects with geometrical precision, so my comments were off base.