bLu vs. tLu: IS confirms 65% conversion factor

[bwaites]

js and jimjones3630,

I have had both positive and negative experiences with UCL coatings.

I actually have had the UCL coating melt off of lenses, particularly the hotter minimag mods where a 1411 Carley is used run by AA LiIon cells.

But I have also had long run 100 watt 64625 Osrams do the same to full size Maglite lenses.

For short runs they seem fine, but prolonged, repeated runs with the larger high output lamps can cause some disintegration. I have not had it happen with a 62138, interestingly, only with the larger 64625 and similar lamps.

I have, however, shattered several UCL lenses with both the 62138 and the 64625 lamps, as well as an overdriven 64623.

As js notes, the borofloat lenses do a better job of taking the intense heat.

Bill

 

[jimjones3630]

lens and bulb held up tonight but the reflector sad to say did not.

64458 90w with 5xemoli 21v hot off charger within 10sec the reflector blistered up like a bad case of chicken pox. It was amazing to watch.

Have not broke any lens to date, have a couple of UCL came with lights I bought. They are mixed up now with boros and don't know how to tell them apart.

 

[LuxLuthor]

Never had a boro lens crack from any of my 90W+ hotwires. JJ, if you had a metal reflector do that, IMHO, there is something wrong with it. What brand (& surface) of reflector & who made it? To date, I have never had a problem with any of FM's metal reflectors in any size, nor the 3" Carley that Delghi recently provided.

 

[js]

Actually, SilverFox had a bad experience with a mag mod with a Carley reflector. And, IIRC, Bill Waites was the maker of the mag mod--do you remember this, Bill?

Anyway, evidently what happened was that there was some kind of water or moisture in the undercoating layer, and when run hot, drops of water would form, fall on the bulb and break the envelope. It was a defective Carley 1940, and as soon as Tom replaced that, everything was fine. It was freaky, though. I was sure the moisture was coming from the PR base potted WA lamp potting material. I never would have guessed it was coming from the reflector. So maybe something similar here?

I, like LL, have never experienced something like that--no blistering or cracking or anything--with a Carley reflector, or a MagCharger reflector. Although . . . come to think of it, my first SF M6 turbo head reflector actually had a spot of the OP coating "melt" and form a flat circular spot on the reflector. I couldn't believe it! And neither could Willie Hunt. My guess is that it was the undercoating that became fluid and flattened out, and the vacuum aluminizing just followed it. Then I exploded an MN20 in that Turbo Head, and SF warranteed it.

As for telling boro and UCL apart, try cleaning them carefully, then look at them obliquely and notice the color of the reflections of things. The UCL with AR coating will have a green or blue tint, and a faintness to the reflection, whereas the boro will act a lot more like normal glass.

 

[jimjones3630]

js thanks for the info. This reflector blistered uniformly around and bottom to top. when it was still hot the blisters were bigger. Looked like could have pealed the whole coating off. I believe Carley is the maker of this reflector.