Another cold elliptical reflector source

chooch · 8th January 2005, 06:31 PM

I came across another company that has cold elliptical reflectors. An interesting note is the average life is rated at 1000h. Does this apply to all cold reflectors or is the life dependent on the type of coating used? If a cold reflector needs to be replaced every few thousand hours, we may as well just take our chances with spherical first surface reflectors.

Gordon

http://www.dwdmfilter.com/reflectors/elliprfl.htm

Me2! · 10th January 2005, 03:33 AM

Make your own ellipse, coat it with heat resistant glue (not contact cement obviously), and press mylar strips ~15degree wedges onto the surface.

How do you make an ellipse? Locate your 2 focuses and tie a loose string to the points. the surface the string sweeps out when you slide something like a small bead along it is an ellipse.

How long for the string, how to anchor the focci, etc you will have to decide based on the size and materials.

ace3000_1 · 10th January 2005, 04:17 AM

Quote:

Make your own ellipse, coat it with heat resistant glue (not contact cement obviously), and press mylar strips ~15degree wedges onto the surface.

LOL, mylar is a fire hazard, its also a very poor surface to reflect light.

Trev

Me2! · 11th January 2005, 03:17 AM

I thought mylar reflected >95%??

"Mylar can be aluminized, allowing reflection of up to 99% of light and heat. Like aluminium foil, aluminized Mylar has a shiny reflective side and a dull side. Mylar does not tear easily, like tin foil and aluminum foil."
from:
http://en.wikipedia.org/wiki/Mylar

You mean I gotta scrape out my new reflector? U sure about a heat hazard?

This is a heat shield made of mylar:

http://www.aircraftspruce.com/catalo...tshieldkit.php

Me2! · 11th January 2005, 03:24 AM

http://www.dupontteijinfilms.com/dat...iew/h67160.pdf

Originally i didnt want to use mylar with a MH bulb, but I think if its not close its ok.

Im still cheesed that I can't use CF bulbs btw.

ace3000_1 · 11th January 2005, 04:15 AM

Quote:

Originally i didnt want to use mylar with a MH bulb, but I think if its not close its ok.

And it wont be close in a reflector? lol. Aluminium foil will burn too. A 250w MH will burn the paint off of a coke can in about 6mins, they run at 300deg c.

One thing you got to look at, how are you going to fit mylar in a sphere evenly? Ill be honest with you, its easier and just as cheap to just buy a reflector, its also safer.

The surface of mylar is no where near as good as a profesional coating. Mylar isnt that flat for starters under a microscope, and the stuff that is, will cost you an arm and a leg.

Trev

ace3000_1 · 11th January 2005, 04:25 AM

Quote:

I thought mylar reflected >95%??

It can, (depending on coating). But in strait lines? nope.

Trev

Me2! · 11th January 2005, 04:28 AM

300C is good to know. Yes, that is above the mylar melt point. So you are saying our projectors can double to roast the spuds in a pinch.

Ive been looking for a good reflector buy havnt had any luck. Ive checked out the film industry par30s- not ideal. Anyone tried the reflector from a multimedia projector after the bulb has burnt out? They have integrated ballasts in the fixture?

TaskMaster · 11th January 2005, 04:28 AM

Where can you buy the reflectors you mean?

Me2! · 11th January 2005, 04:30 AM

Yes, I would greatly appreciate a tip on reflector sources.

8th January 2005, 06:31 PM	#1
chooch diyAudio Member Join Date: Oct 2004	Another cold elliptical reflector source I came across another company that has cold elliptical reflectors. An interesting note is the average life is rated at 1000h. Does this apply to all cold reflectors or is the life dependent on the type of coating used? If a cold reflector needs to be replaced every few thousand hours, we may as well just take our chances with spherical first surface reflectors. Gordon http://www.dwdmfilter.com/reflectors/elliprfl.htm

11th January 2005, 03:24 AM	#5
Me2! diyAudio Member Join Date: Dec 2004 Location: BC	dupont mylar specs http://www.dupontteijinfilms.com/dat...iew/h67160.pdf Originally i didnt want to use mylar with a MH bulb, but I think if its not close its ok. Im still cheesed that I can't use CF bulbs btw.

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10th January 2005, 03:33 AM	#2
Me2! diyAudio Member Join Date: Dec 2004 Location: BC	Make your own ellipse, coat it with heat resistant glue (not contact cement obviously), and press mylar strips ~15degree wedges onto the surface. How do you make an ellipse? Locate your 2 focuses and tie a loose string to the points. the surface the string sweeps out when you slide something like a small bead along it is an ellipse. How long for the string, how to anchor the focci, etc you will have to decide based on the size and materials.

11th January 2005, 03:17 AM	#4
Me2! diyAudio Member Join Date: Dec 2004 Location: BC	I thought mylar reflected >95%?? "Mylar can be aluminized, allowing reflection of up to 99% of light and heat. Like aluminium foil, aluminized Mylar has a shiny reflective side and a dull side. Mylar does not tear easily, like tin foil and aluminum foil." from: http://en.wikipedia.org/wiki/Mylar You mean I gotta scrape out my new reflector? U sure about a heat hazard? This is a heat shield made of mylar: http://www.aircraftspruce.com/catalo...tshieldkit.php

11th January 2005, 04:28 AM	#8
Me2! diyAudio Member Join Date: Dec 2004 Location: BC	300C is good to know. Yes, that is above the mylar melt point. So you are saying our projectors can double to roast the spuds in a pinch. Ive been looking for a good reflector buy havnt had any luck. Ive checked out the film industry par30s- not ideal. Anyone tried the reflector from a multimedia projector after the bulb has burnt out? They have integrated ballasts in the fixture?

11th January 2005, 04:28 AM	#9
TaskMaster diyAudio Member Join Date: Jan 2005 Location: USA	Where can you buy the reflectors you mean?

11th January 2005, 04:30 AM	#10
Me2! diyAudio Member Join Date: Dec 2004 Location: BC	Yes, I would greatly appreciate a tip on reflector sources.

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