why silicone o-rings?

luminata

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Jun 6, 2006
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335
Why do all (as far as I can tell) flashlight makers use Silicone based O-rings. they dont seem very tuff against real world environments. I have seen a material called Kalrez which seems to be superior in all apsects to any other o-ring material. Especially in high end lights why not use the best in o-rings? anyone know where to get o-rings in this material?
 

Flash_Gordon

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Apr 3, 2005
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Most do not use silicone o-rings. Most are Nitrile (Buna-N). Silicone's only big advantage is at extremes of temperature. They have poor tear and abrasion strength and poor resistance to oils.

Where silicone is used, they can usually be spotted by their red or orange color. One use is around bulbs where they pass through the reflector-Streamlight, for example. This is a high temperature use.

Mark
 

luminata

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Jun 6, 2006
Messages
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aaahh i see. So if I ordered orange orings from DX they are going to be inferior? great .
 

Biggoggs

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Apr 24, 2007
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Australia
If most flashlight o-rings are nitrile, then shouldn't you be able to use any sort of grease/oil for lubrication (petroleum/non-petroleum)?
 

Flash_Gordon

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If most flashlight o-rings are nitrile, then shouldn't you be able to use any sort of grease/oil for lubrication (petroleum/non-petroleum)?

Yes, but with some limitations. Nitrile with rated as good resistance to petroleum, hydrocarbons, fuels.

Problems can arise when we may pick up any one of hundreds of off the shelf lubricants. We do not know what all (or maybe any) of the components are.

For those interested, here is a link to o-ring fluid compatibility.

http://www.allorings.com/compatibility.htm

Chemistry buffs enjoy!

Since most flashlight manufacturers recommend using silicone on o-rings, why work so hard to reinvent the wheel?

Mark
 
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