UCL or Borofloat?

I intend on ordering a replacement flashlight lense from flashlightlense.com for use in a modified 2C Mag that will be putting out upwards of 250 lumens. Which lense would you recomend and why?

Thank you in advance for your reply,
Dale

For me I would recommend UCL since it's the clearest there is. If you are not going to subject it to too much thermal shock (hot and sudden cold or cold and sudden hot) I think it should be pretty good.

I have UCL's on my SL-35 and SL-20X's and like them. The UCL's have no problem with the 20W LA, so they wouldn't object to the 12 Watts or so you plan to use. Borofloat may have a higher ultimate temperature capablilty than UCL, but it is probably outside your range of concern.

I have no other Flashlightlens products at present because I bought a bunch of Mag Charger tempered glass lenses that I use on various Mags including the original 4 * 123 plus potted Carley 9.6 V 1.2 A bulb. I'm happy enough with the tempered Mag lens that I've not felt the need to replace. The UCL would probably transmit a few percent more lumen though.

It never occurred to me to ask what the relative transmission of IR waves is between various lens glasses. This could conceivably make a difference in retained heat and the Mag Polycarbonate reflector that is rated stable only to 320 degrees F.

At almost double the price for the UCL's and the Borofloats have more shock resistance, I would go with them. I replaced my two Mag's with them and am very pleased. By the way, they are VERY CLEAR!

if you are in a place where you might be dropping the light in the snow, it might be best to take advantage of the borofloats thermal shock resistance. if you are not worried about quick temperature change, and you want all the bells and whistles (extra clear, anti-glare, anti-reflective etc.) then go with the ucl.

I do not know about UCL but borofloat has excellent IR transmission characteristics. It easily outstrips tempered glass (and of course polycarbonate). I know this from comparing the schott borosilicate spectra with that of glass. Boro does better on both ends of the spectrum (UV and IR).

Chris of flashlightlens did a test with Randy of TL regarding the thermal shock of glass lens. Very skunkworks. I'm sorry I don't have time to link the post. I think it's the very long one in the Dealer section.

Anyway, the TL with UCL was left bezel-down on a desk for a while to heat the lens, then the bezel was shoved into a bowl of snow. No problem.

Originally posted by binky:
....Anyway, the TL with UCL was left bezel-down on a desk for a while to heat the lens, then the bezel was shoved into a bowl of snow. No problem.

Click to expand...

<font size="2" face="Verdana, Arial">Wasn't that the post where he said something about the UCL lens actually protecting against thermal buildup because of its unusual efficiency at passing infrared, or something to that effect?

Brightnorm

Hey Everyone,
Binky nailed it on the head. We left a TL bezel-down on a desk for about 5 minutes and then stuck it right into a bowl of snow. It handled it fine. There was a little condensation on the inside of the lens, but it didn't break.

Brightnorm - With the lens allowing more light energy to escape the LA, the UCL lens should allow the LA to remain cooler. I've been looking for an excuse to pick up a temp probe to run some tests - I guess I just found one.....

Chris

Perhaps I should have phrased my question as follows. Does the 5 or so percent increase in light transmission outway the increased durability provided by the Borofloat lense. My understanding is the Pyrex allows somewhere around 95% light transmission, and with borofloat supposedly a close rival, I would expect similar results. If I am to only see an increase of around 5% light transmission from the UCL, then I think that I will go for the increased durability of the borofloat lense.

Respectfully,
Dale

I have a few spare mag polycarbonate reflectors. I'll see what happens with a to-be-ordered custom potted by Carley W/A bulb in the 14W to 18 W range and the M/C tempered lens. I'll see how long the reflector takes to deform.

If the Mag reflector does deform, I'll order a Mag UCL and see how much longer another reflector takes to deform. Maybe, for example, 14W will be a "go" with a UCL and a "meltdown" with the M/C tempered lens.