Re: [APD] DIY reflector?

["S. Hieber" <shieber at yahoo_com>]

General Rule of Thumb Values for the Reflectivity of Various materials:

Black Less than                        10% 
Aluminium Foil                         55-70% depending on specularity
Semi-gloss White Paint             60-70%  depending on binders and resins, which yellow with age and UV exposure, and the types of flatteners used.
Flat White Paint                         75-80%  depending on binders and resins, which yellow with age and UV exposure, and the types of flatteners used.
Polystyrene Foam Sheeting        75-85% 
Mylar Sheeting                            60-92% depending on the quality of the metal coating and clarity of the mylar.
Miro (a brand name for a 
  specific range of types
  PVD coated aluminum, 
  also known as Multi-layer 
  Optical Coating Aluminum)         up to about 94-95%
 
Btw, "PVD" isn't for a character from Oz, it means Physical Vapour Deposition, which is a method of applying coatings to surfaces.

You can dig into the tons of stuff written on this and come up with variations in the numbers. The specific kind of materials, the curve or angles of reflectors and the distance of the bulb from the object and the reflector. . . all these things can make big diffs in overall performance of a lamp getting light to a desired surface. But generally, I believe this is a good guideline. The APD archives too have a whol elot of stuff on reflectance, specularity, and other topics peculiar.
 
sh
 
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----- Original Message ----
From: Chris Ferrell <cferrell at gmail_com>
To: aquatic-plants at actwin_com
Sent: Thursday, July 20, 2006 9:29:58 AM
Subject: Re: [APD] DIY reflector?


I've cut a thin-walled, 4" PVC pipe in half and used each side to attach to
the sides of a shop-light.  I left the sides open to help with airflow and
heat.  Since you didn't mention the looks of the thing, that's probably what
I'd do.  The white of the PVC will work well enough as a reflector to get
what you need for light.  The extra PVC will help prevent light-spillage
into the rest of the room.

I've also gone a step further and made a reflectors in an "M" shape with the
same two pieces of PVC.  You would probably need to gut the shoplight and
have more DIY work done here to make sure everything works, but it makes for
a quick and dirty reflector.  If you've seen the AH Supply 13 watt
reflectors, that's sort of the end result  (but not faceted).

Hope that helps,
Chris
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