How scratch resistant is SF "pyrex"?

Now that I have my E1L, I wouldn't mind just tossing it in my backpack or vehicle but don't want to scratch the lens. What does it take to scratch it?

Thx,
Snes

The Pyrex doesn't scratch very easily, but the ano. will scratch if you breathe on it to hard.

How would you compare the scratch resistant of Pyrex against Sapphire Crystal ?

I haven't been able to put a single scratch on my pyrex lens for a year now, I am carrying in my backpack quite often (gets in touch with hard cordura and items in my bag).

I think it's pretty close to a saphire crystal in terms of scratch resistance?

Snesley Wipes said:

Now that I have my E1L, I wouldn't mind just tossing it in my backpack or vehicle but don't want to scratch the lens. What does it take to scratch it?

Thx,
Snes

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I wouldn't mind about scratching it! If it ever breaks, give a call to SureFire and they will solve your problem!

senna94 said:

The Pyrex doesn't scratch very easily, but the ano. will scratch if you breathe on it to hard.

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Ano?

Anodizing. The finish used on surefires and many others.

Corning Pyrex (borosilicate glass) has a Mohs hardness of 5.5, about the same as steel. If the abrasive is harder than 5.5, it will scratch both steel & Pyrex.

Sapphire (single crystal aluminum oxide, Al2O3) has a Mohs hardness of 9, almost double that of Pyrex ... diamond is 10.

Although not as hard as Sapphire, Pyrex has a maximum use temperature of 490° C (914° F), and has excellent thermal shock resistance.

Re: How scratch resistant is SF "Pyrex"?

http://www.rayotek.com/techincal_info_glass_sapphire.htm

https://www.candlepowerforums.com/threads/58353


Research and search are your friends.


Sapphire is extremely resistant to scratches.
It also transmits less light and is much more expensive.

McGizmo (some) custom(semi) come with sapphire windows.

I have found the window/optic on my new E1B to be very scratch resistant. The stuff seems pretty darn tough.

That said I do not make a habit of scratching up my flashlights.
I can't remember the last time I scratched a front glass on a flashlight.
regardless of material.
Yaesumofo

Pyrex is the glass that is used for most chemical laboratory items, e.g. beakers, flasks, etc. Pyrex glass is pretty much resistant to everything, including toluene to a degree. Anyway, it's incredibly scratch resistant.

I can't remember the last time I scratched a front glass on a flashlight.
regardless of material.

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When the glass (or Lexan on the 120P) gets dirty, I hold the light, lens up, under warm running water. Put a drop of liquid soap on the lens, swirl that around with a fingertip, dry with a soft cloth & you're good to go.

*off topic* -I have had my Tag Heuer for 8yrs now with a sapphire crystal face/lens and not a scratch. It's been thru some times too!

I had a huge gash in the Sapphire lens on my Seiko I've been wearing for 10 years. I have no idea what put it there (right through the titanium shell and lens) but I was always happy that whatever it was didn't make contact with my wrist. I just recently had a mechanical failure that required it to go back to Japan and I had them replace the crystal too. I'm not sure that was a good idea, I kind of miss the old one.

Hmm...

I recieved a watch as a holiday work gift and I thought it was just a cheesy cheap watch until I noticed that the glass never scratched. It's a brand I've never heard of 'Berenger' and it looks like crap now since the stainless is all dinged up but at least the glass looks nice, LOL.

all my Pyrex windowed lights(Surefires) don't have any scratch on them, some of them live in the same compartment as keys, multitools and screw drivers.

precisionworks said:

Sapphire (single crystal aluminum oxide, Al2O3) has a Mohs hardness of 9, almost double that of Pyrex ... diamond is 10.

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In reality I have yet to see a flashlight application or instance that this extra hardness makes a difference. I don't believe I've ever seen or heard of a SureFire Pyrex window being scratched.

precisionworks said:

Although not as hard as Sapphire, Pyrex has a maximum use temperature of 490° C (914° F), and has excellent thermal shock resistance.

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This 490C maximum is lowered as a result of it being used in an application where the glass is physically constrained by [especially] metal components, even where gaskets and o-rings are used. However, the safe working temperature will still be far beyond that which a flashlight can achieve, even in failure so the glass isn't going to deform.

Al

Mercaptan said:

Pyrex is the glass that is used for most chemical laboratory items, e.g. beakers, flasks, etc. Pyrex glass is pretty much resistant to everything, including toluene to a degree. Anyway, it's incredibly scratch resistant.

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Actually, pyrex is not really any more resistant to chemical attack than other types of glass (toluene cannot damage ANY type of glass, generally only some strong acids and bases will react with glass). Lab Pyrex is also called borosilicate glass (bacause it contains a boron oxide additive) and is used for lab glassware for one reason only: because it has a significantly lower coefficient of thermal expansion than normal glass. This makes it much more resistant to thermal shock, ie, rapid heating and cooling will not usually cause it to crack. The heat from most flashlights is not likely to have any effect. Apparantly the Pyrex name can also be used for soda-lime glass - I'm not sure what grade Surefire is using but I suspect lab grade.

Anyway, I too have never seen any hint of scratching on my Surefire L2 lens (or the ano for that matter, except a couple nicks), although I have seen plenty of lab-grade Pyrex scratch, its not terribly scratch resistant. Synthetic sapphire is an amazingly scratch resistant material which is ideal for watch crystals which I'd say are far more likely to encounter hard materials than a flashlight lens, and scratches in them are also far more noticable IMO. Sapphire is probably overkill for a flashlight, but I like the idea anyway.

NB, the Mohs hardness scale is a relative scale, the numbers have no other significance except to indicate one material being harder than the next. Something with a mohs hardness of 8 is way more than twice as hard as something with a hardness of 4 if you use an absolute scale.

senna94 said:

The Pyrex doesn't scratch very easily, but the ano. will scratch if you breathe on it to hard.

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SureFire's HA has been very durable in my experience.

warlord said:

Hmm...

I recieved a watch as a holiday work gift and I thought it was just a cheesy cheap watch until I noticed that the glass never scratched. It's a brand I've never heard of 'Berenger' and it looks like crap now since the stainless is all dinged up but at least the glass looks nice, LOL.

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I received a stainless steel "Coleman" watch as a holiday gift and has worn the watch through sand blasts, dirt, metal shavings and stones ... the stainless is all scratched up but the glass is clear as day ... not one scratch. Now my Surefire L2 lens has tiny scratches on it from falling into sand and stones.

sims2k said:

Now my Surefire L2 lens has tiny scratches on it from falling into sand and stones.

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I'd like to see some photos if you can share them please