DIY - glass mirrors in the fixture?

Pszemol · 07-20-2002, 02:58 PM

I noticed, everybody is using polished aluminium in their PC/VHO reflectors.
What about thin glass mirrors? If I cut strips of glass and form a reflector with them - would they work better than aluminium reflector?
If I form strips the way they overlap but they do not stick to each other I would let hot air to circulate better between gaps...

Let's say like that:
------ ..... top mirror reflecting light strigth to water
/ oo \ ..... PC/VHO bulb surrounded with two, side mirrors fixed on an angle
~~~~~ ..... water surface

Hot air will circulate up from the bulb between mirrors and up to the vents in the fixture behind mirrors... What do you think about this idea?

Zephrant · 07-23-2002, 01:02 AM

On the surface (pun intended), glass mirrors sounds like a good idea, and I tried it some time ago on a 55 with FL lights. However it is the "glass" portion of the mirror that hurts- Assuming the glass is normal, 90% Transmissive, you loose 90% of the light going though it to hit the mirrored surface, then 90% of the remaining light on the way back out.

Net loss: 19% of the light, or 81% of the light gets reflected back.

Using plexi-glass mirror is slightly better, 92% in, 92% out = 85% usable light.

A good specular aluminum reflector gets in the high 90's for reflected light I believe.

Zeph

Pszemol · 07-23-2002, 01:22 AM

hm... thanks... I did not think about that...
It is so obvious after you've describe this :-)

07-20-2002, 02:58 PM	#1
Pszemol Just Moved In Join Date: Jan 2002 Location: La Grange, IL Posts: 42	DIY - glass mirrors in the fixture? I noticed, everybody is using polished aluminium in their PC/VHO reflectors. What about thin glass mirrors? If I cut strips of glass and form a reflector with them - would they work better than aluminium reflector? If I form strips the way they overlap but they do not stick to each other I would let hot air to circulate better between gaps... Let's say like that: ------ ..... top mirror reflecting light strigth to water / oo \ ..... PC/VHO bulb surrounded with two, side mirrors fixed on an angle ~~~~~ ..... water surface Hot air will circulate up from the bulb between mirrors and up to the vents in the fixture behind mirrors... What do you think about this idea?

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07-23-2002, 01:02 AM	#2
Zephrant Reefer Join Date: Jul 2002 Location: Spokane, WA Posts: 9	On the surface (pun intended), glass mirrors sounds like a good idea, and I tried it some time ago on a 55 with FL lights. However it is the "glass" portion of the mirror that hurts- Assuming the glass is normal, 90% Transmissive, you loose 90% of the light going though it to hit the mirrored surface, then 90% of the remaining light on the way back out. Net loss: 19% of the light, or 81% of the light gets reflected back. Using plexi-glass mirror is slightly better, 92% in, 92% out = 85% usable light. A good specular aluminum reflector gets in the high 90's for reflected light I believe. Zeph

07-23-2002, 01:22 AM	#3
Pszemol Just Moved In Join Date: Jan 2002 Location: La Grange, IL Posts: 42	hm... thanks... I did not think about that... It is so obvious after you've describe this :-)

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