Malkoff's use of Hard Acrylic Lenses...why?

Gene Malkoff is not known for sparing money, or engineering on his products. He chose to use a "hard coat acrylic" lens on the MDC's as well as the VME heads.

Why?

It has a few % more transmission than Pyrex, but how does it compare otherwise? It is abrasion resistant, allegedly, but how does it really hold up over the long term compared to a pyrex lens. Does anyone have any experience, here? I know there is a reason he chose this material and configuration, I just don't know the reason. I do know it wasn't to shave a few penny's, though, so...what are the real-world advantages, especially on a "tactical" flashlight like some of the MDC's are meant to be, as well as the collaborative venture between Malkoff and ROSCH Works.
http://roschworks.com/

Shatter-resistance, would be my guess ....

You are quite right archimedes, Just last week Gene said he went for shatter-resistance over light transmission to futher toughen his lights. I know most of these lights were designed for the rigors of law enforcement. I can tell you from personal experience I've dropped my Hound Dog several times over my first year of ownership and never had a lens crack.

Once upon a time, Malkoff lights were built with glass (maybe UCL) lenses. After replacing so many glass lens (shattered) due to hard use, the glass lens were no longer used.

All of my Surefire weapon lights have a glass lense. Pyrex. They geat beat up 1-2" from the muzzle of short-barreled 5.56 weapons, their housings are pecked from debris from living 1" past the end of my Glock 19 barrel, etc. UCL is pretty brittle, but Pyrex is tough stuff.

How abrasion resistant is the coated Acrylic, comparably? I think heat and abrasion are the real enemy of a weapon light, and definitely abrasion is the enemy of the EDC/pocket-carry. Impact, too, yes, but I feel that Pyrex is some seriously tough stuff, and Mr. Malkoff chose Acrylic over it.

Broken lens may (potentially) render torch non-functional .... Abraded lens might only diffuse / distort the beam

If you prefer scratch- ( & heat- ) resistance to shatter-resistance, you could choose to replace the lenses with sapphire crystal ....

The hardcoat on my G2's lexan lens was very durable, right up till I got some gunscrubber on it. Abrasion wise I've actually seen less scratches on hardcoats than on glass, I've had my eyeglasses skate across concrete before with just some hard to see scuffing. I've noticed the coatings tend to break down after some time though, especially when they're in contact with oils or other contaminants.

N/Apower said:

All of my Surefire weapon lights have a glass lense. Pyrex. They geat beat up 1-2" from the muzzle of short-barreled 5.56 weapons, their housings are pecked from debris from living 1" past the end of my Glock 19 barrel, etc. UCL is pretty brittle, but Pyrex is tough stuff.

How abrasion resistant is the coated Acrylic, comparably? I think heat and abrasion are the real enemy of a weapon light, and definitely abrasion is the enemy of the EDC/pocket-carry. Impact, too, yes, but I feel that Pyrex is some seriously tough stuff, and Mr. Malkoff chose Acrylic over it.

Click to expand...

Abrasion resistant acrylic will crack and tear if abused while polycarbonate will stretch. Both will scratch if you rub something abrasive against it, but, AR acrylic can take more abuse before you see any scratches while polycarbonate will scratch if you clean it with a soft cloth. You can abuse polycarbonate and it won't tear nor crack. Here is a picture of the polycarbonate lens from my 9N that I removed. Even after trying to drive a 1" aluminum rod through the lens to push it from the bezel it didn't budge. It stretched, which made it nearly impossible to remove. I had to cut a slot into it in order to remove it.



AR acrylic has a slightly better light transmittance rating than polycarbonate, which, combined with the abrasion resistance, is probably why they chose to use it.

Why does SF use Pyrex? What makes Pyrex unique? Pyrex can withstand thermal shock really well which makes it ideal for use with hot incandescent bulbs, but, what advantage would it give you when used with a much cooler LED? None that I can think of. What are the negatives of using Pyrex? It'll shatter if impacted and it probably has relatively poor light transmittance compared to a UCL or acrylic. For LED, AR acrylic makes a lot of sense.

For an EDC, I can see that. Thanks for the summaries, all!

What is recommended to coat the lens with on my SBR (it will live within about 2" of the muzzle)? It's going to get sooted up fast and will be a real pain to clean if I don't put something on it. I understand ANY petroleum based product is bad, but what about vegetable or sunflower based "bio" oils?

This is a hard-coat Acrylic lens from Malkoff (Left, smaller) compared to a UCL lens. Both were pressed and dragged across roughly 3" of 100 grit sand-paper as evenly-pressured as my hands could get them. The Acrylic had noticeably more drag.

A bit of context helps here.

Malkoff dropins didn't used to need lenses. So Malkoff hosts and heads were designed without them. When the 61s came along and ditched the optic, lenses were suddenly critical. The choice was between redesigning hosts or going with a lens thinner than other setups.

Pyrex and UCL lenses are less prone to scratches but are more prone to breaking. Only when as thick as found on say a z44, do they hold up to heavy uses. As thin as they needed to be to work in existing hosts, glass was not holding up - so acrylic instead. The upside to this approach is these hosts can be several mm shorter than thicker lens hosts.

ElectronGuru said:

A bit of context helps here.

Malkoff dropins didn't used to need lenses. So Malkoff hosts and heads were designed without them. When the 61s came along and ditched the optic, lenses were suddenly critical. The choice was between redesigning hosts or going with a lens thinner than other setups.

Pyrex and UCL lenses are less prone to scratches but are more prone to breaking. Only when as thick as found on say a z44, do they hold up to heavy uses. As thin as they needed to be to work in existing hosts, glass was not holding up - so acrylic instead. The upside to this approach is these hosts can be several mm shorter than thicker lens hosts.

Click to expand...

I had not thought of that at all. You're absolutely right on how thick the glass is on a Z44. I don't know how thick it is on my X300U weapon light, so I can't comment there, but I bet it's thicker than Malkoff uses, as well.

N/Apower said:

For an EDC, I can see that. Thanks for the summaries, all!

What is recommended to coat the lens with on my SBR (it will live within about 2" of the muzzle)? It's going to get sooted up fast and will be a real pain to clean if I don't put something on it. I understand ANY petroleum based product is bad, but what about vegetable or sunflower based "bio" oils?

Click to expand...

In that situation, if it doesn't burn through, I'd just put a layer of clear packing tape over the head of the light, or some kind of clear cling-type window film like they have for smartphones. When it gets sooted up, just peel and replace.

N/Apower said:

For an EDC, I can see that. Thanks for the summaries, all!

What is recommended to coat the lens with on my SBR (it will live within about 2" of the muzzle)? It's going to get sooted up fast and will be a real pain to clean if I don't put something on it. I understand ANY petroleum based product is bad, but what about vegetable or sunflower based "bio" oils?

Click to expand...

Coat it with SLIP or something similar prior to use. Some use WD40. Nothing prevents gunk buildup, but this makes cleaning a simple wipe-off affair. Clean with a pencil eraser, if needed, or use toothpaste - makes a great cleaner.

Try not to obsess too much about a few scratches. It's a tool, not a jewel.

dss_777 said:

Coat it with SLIP or something similar prior to use. Some use WD40. Nothing prevents gunk buildup, but this makes cleaning a simple wipe-off affair. Clean with a pencil eraser, if needed, or use toothpaste - makes a great cleaner.

Try not to obsess too much about a few scratches. It's a tool, not a jewel.

Click to expand...

I agree fully, but scratching stuff up leads to junk getting held in the scratches. I turned my X300U from a 500 to about a 200 lumen light in about 500 rounds with all the gunk build-up. If I am only running 250 OTF lumens, I want ALL of them, not 220, etc. I believe I've convinced the developer of the product to T&E some sapphire lenses, and have been promised one. All is well that ends well

OCD? Yes, but functionally

N/Apower said:

I believe I've convinced the developer of the product to T&E some sapphire lenses, and have been promised one.

Click to expand...

You've possibly convinced which developer to T&E some sapphire lenses? I've bought a few sapphire lenses from The Sandwich Shoppe for MD2 and VME heads and they've help up very well. I almost bought a couple more earlier this week.

Grizzman said:

You've possibly convinced which developer to T&E some sapphire lenses? I've bought a few sapphire lenses from flashlightlens.com for MD2 and VME heads and they've help up very well. I almost bought a couple more earlier this week.

Click to expand...

http://roschworks.com/

They are going to be polite enough to send me a unit with a sapphire lens for evaluation. I have previously used the same lens on a VME conversion head on an M300 Surefire Scout, and it held up GREAT living in the muzzle-blast of my 10.5" 5.56. The project is a collaboration between ROSCH Works, and Gene Malkoff.

http://theledguy.chainreactionweb.com/product_info.php?products_id=809

Oh ya, I now recall seeing the Rosch link, but I was at work and it was blocked by corporate Internet filters. I will check it out this evening.

Okay, so I found a sapphire lens that EXACTLY matches the OEM lens size in this product. My problem? What the heck do I use to remove the bezel? You guys are pretty bright and have lots of work-around advise, I am sure. Looking for some of that, now:

The measurement on the caliper is the distance from the inside of two opposing notches ( a HAIR over 0.8"). There are 8, semi-rounded as depicted in my crummy photo.

In a pinch on Z44 surefire bezels I have made a simple wedge device out of Kydex which is pretty easy to work with. I just cut and snipped a wedge to fit between the notches with emough excess to make a handle for my fingers. This wont scratch the lens . Takes a little trial and error to get a tight fit on a particular bezel. I also always heat up the bezel in boiling water multiple times before attemtping and that always helps. Using snapring pliers has always resulted in damaging something. I would contact the maker of the light and ask if they use loctite on the bezel ring. I bet they do as its a weapon light . they might evem have a tool . They seem very accomodating?