# Reflector coatings/surfaces



## cat (Nov 23, 2007)

What are the various light reflector coatings/surfaces? 

*electroless nickel*
(I read somewhere that there's a significant loss of light with it.) 

*polished aluminium*
(Greater loss of light than electroless nickel?) 

What is commonly used on our flashlights - on the aluminium reflectors? 
What about "plastic chrome" (whatever the correct name is?) (That would be what the plastic reflectors are done with.) 

:thinking:


----------



## 65535 (Nov 24, 2007)

I believe it's a mirrorized PVD aluminum coating.


----------



## cat (Nov 24, 2007)

Thanks. Plenty to sift through on google. Found this - silver with silica coating - sounds good):



> A reflector lamp has a generally parabolic shaped housing (12) with an interior surface coated with a layer (14) of silver having a protective layer (16) of a stable protective material, such as silica, disposed thereon.


----------



## Nereus (Nov 24, 2007)

Cat, I guess that you may find this thread interesting.

-N


----------



## saabluster (Nov 24, 2007)

cat said:


> Thanks. Plenty to sift through on google. Found this - silver with silica coating - sounds good):


I just sent off three of my reflectors to be recoated in 99.999% pure AL with an overcoat of SiO2. Should give me a good boost in output.:twothumbs I took readings of two of my lights before I sent it off so I could compare it after I get it back. I'll try to remember to post the results.


----------



## vetkaw63 (Nov 25, 2007)

saabluster said:


> I just sent off three of my reflectors to be recoated in 99.999% pure AL with an overcoat of SiO2. Should give me a good boost in output.:twothumbs I took readings of two of my lights before I sent it off so I could compare it after I get it back. I'll try to remember to post the results.



Please do. I have been waiting since your first post about this. Can you give us a price estimate yet?
Thanks,
Mike


----------



## saabluster (Nov 25, 2007)

vetkaw63 said:


> Please do. I have been waiting since your first post about this. Can you give us a price estimate yet?
> Thanks,
> Mike


He gave me a really good price and I don't know if he wants me telling everyone. The reason for the good price is he has never coated flashlight reflectors before and I'm somewhat of a guinea pig on this. He normally coats telescope reflectors so I'm sure his workmanship will be good. To be honest the prices he quotes for his telescope coating is not bad at all. But I can't tell you what kind of prices he will give us on a regular basis.


----------



## cat (Nov 25, 2007)

Nereus said:


> Cat, I guess that you may find this thread interesting.




Thank you, Nereus! :thumbsup:


----------



## jason9987 (Nov 27, 2007)

saabluster, could you give us the website or some contact info for the place you are getting reflectors coated? I have an HDS that I destroyed the reflector trying to clean it and you cant get replacements anymore.


----------



## saabluster (Nov 27, 2007)

jason9987 said:


> saabluster, could you give us the website or some contact info for the place you are getting reflectors coated? I have an HDS that I destroyed the reflector trying to clean it and you cant get replacements anymore.



Don't you want to wait and see if it will even work? This is this guys first time to coat flashlight reflectors.


----------



## vetkaw63 (Nov 28, 2007)

When do you expect to get your reflectors back?
Mike


----------



## will (Nov 28, 2007)

saabluster said:


> Don't you want to wait and see if it will even work? This is this guys first time to coat flashlight reflectors.



I would think if he is doing telescopes reflectors, a flashlight reflector is going to be easier. You don't really have to be concerned with image quality, like on a telescope.


----------



## Nubo (Nov 28, 2007)

will said:


> I would think if he is doing telescopes reflectors, a flashlight reflector is going to be easier. You don't really have to be concerned with image quality, like on a telescope.




Exactly. Telescope mirrors are rated to an accuracy of a fraction of a wavelength of light. A flashlight reflector could be much worse and you wouldn't know the difference. I would also think that this means the coating could be made quite a bit thicker.


----------



## saabluster (Nov 29, 2007)

will said:


> You don't really have to be concerned with image quality, like on a telescope.


True. But he normally deals with coating very shallow curved glass. I gave him deeply curved plastic and metal. It may be easier I don't know. He didn't tell me. 
As far as when I get it back. I don't know. I e-mailed him yesterday and I'm still waiting on a response.


----------



## cat (Nov 29, 2007)

hey, it is *different*, ok? Different material, different shape, different size. So maybe different temperature, different position in tank, different voltage, etc. It is _not_ like electro-plating.


----------



## will (Nov 29, 2007)

I believe the process used is vacuum deposition, which is not like electro plating or chemical plating.


----------



## saabluster (Nov 29, 2007)

Well I just talked with him and he is having issues with the plastic off gassing and messing up the finish. He is going to try again tonight.


----------



## buschpounder (Dec 2, 2007)

Have the reflectors been finished? Curious of the results. Thanks


----------



## saabluster (Dec 2, 2007)

buschpounder said:


> Have the reflectors been finished? Curious of the results. Thanks



I should be getting them back this week.


----------



## vetkaw63 (Dec 3, 2007)

So, the reflectors turned out ok? You just need to see if the improvement was worth the time and money spent?
Mike


----------



## saabluster (Dec 3, 2007)

vetkaw63 said:


> So, the reflectors turned out ok? You just need to see if the improvement was worth the time and money spent?
> Mike


I don't know yet. I let you know as soon as I do.


----------



## vetkaw63 (Dec 4, 2007)

Sorry, I meant to ask if they were successfully coated. Now you just need to test them?
Thanks,
Mike


----------



## LumenHound (Dec 4, 2007)

Did the recoater give you a specific % of reflectivity they were aiming for or was it more like a "We'll do our best" sort of thing?

90-95%?


----------



## saabluster (Dec 4, 2007)

vetkaw63 said:


> Sorry, I meant to ask if they were successfully coated. Now you just need to test them?
> Thanks,
> Mike


Yes he was able to get the aluminium to adhere. We'll see how good the quality is.


----------



## saabluster (Dec 4, 2007)

LumenHound said:


> Did the recoater give you a specific % of reflectivity they were aiming for or was it more like a "We'll do our best" sort of thing?
> 
> 90-95%?


I seem to remember his ad saying 90-91% which should be right for the materials he is using. This will be somewhat dependant on how well I resurfaced one of them. The reflector out of the "super thrower" was not perfectly formed so I tried to sand and polish it in hopes of improving it.


----------



## jimjones3630 (Dec 5, 2007)

I'd like to know how this coating comes out as well. looking for someone to do a reflector with max heat resistance


----------



## cat (Dec 6, 2007)

That would be a useful standard, and to know which setups are too hot for the reflectors that are generally used. 

The silicate outer coatings are used for heat as well as abrasion resistance, so it would be out of the scope of most PVD shops. The "plastic chrome" stuff is done with a sort of exploded electrode. The silicate/glass overcoating must be some sort of molten process.


----------



## saabluster (Dec 8, 2007)

Well I got them back. On my WF-500 tri-reflector the output is up marginally. About 2% for overall output. So reflectivity is around 4% up. Not what I was hoping for but better than nothing. 

The Super Thrower's however came in at a -20% loss. Not in total output, that was about -10%, but in the amount of light attributable to the reflector. Roughly half of the light from the LED hits the reflector so if the total output is down 10% its reflectance is actually down 20%. 

Not real happy with this but I think there is hope. Part of the reason is my poor polishing job. I did not do an optical quality job. Second it appears about a 1/4th of the reflectors coating is too thin. Keep in mind this is this guys first time to do flashlight related stuff and he ran into problems. I'm going to re-polish the reflector and try again.


----------



## 65535 (Dec 9, 2007)

Can you post pics? Before and after polish/removal.


----------



## saabluster (Dec 10, 2007)

65535 said:


> Can you post pics? Before and after polish/removal.


I will do what I can. I think it will be hard to capture with a camera but I'll try.


----------

