KPR113 vs KPR112 in 3x123 2C Mag

[cratz2]

So... I finally built a 3x123 2C Mag. I haven't bought any KPR112 bulbs yet but will shortly assuming I can find some in stock but for now, I'm using a KPR113. They are Energizer brand from The Home Depot billed as standard 4 D cell bulbs.

KPR112 is 6.0V 650 mA
KPR113 is 4.8V 700 mA

These are both Radio Shack specs. I've read on several threads that the 112 may have very short lifetime or may even almost instaflash. If the 112 is that stressed, should the 113 not be even more stressed? Is there something I'm missing? I ran my light off and on for about 30 minutes last night including turning it off and on literally 300 times. Batteries were Surefires fresh from the box.

What gives? I know about the 6V vs 4.8V rating, but... but... I'm sure someone else has used these bulbs in the 3x123 build.

 

[PlayboyJoeShmoe]

Doesn't seem right...

The common bulb is KPR112 but I run M*g Krypton Star 5 cell bulb myself.. easier to come by!

Why the 4.8V bulb doesn't go boom is a mystery. Perhaps like one of my 2D M*gs, you have a serious resistence problem in that light? When I get my stuff out of storage after the move, I'm going to disassemble and clean and then hotrod that 2D!!!

 

[bjn70]

The KPR112 is supposed to last 30 minutes or so which is pretty short life but I don't remember people talking about instaflashing with 3 CR123's. How long did your batteries last? I've heard that they will last only about 30 minutes and the bulb may or may not last as long as the batteries.

 

[cratz2]

I had my light off an on last night (the night I built it) for over 30 minutes and the batteries and KPR113 bulb were both still going strong. I picked up two KPR112 batteries from Radio Shack this evening and while I can't compare the 112 to the 113 as I only have one light modded, they look very comparably bright. I turned the same 113 bulb off and on 100 times this evening and the 112 bulb off and on 100 times. I'd guess that right now, I have 40 to 45 minutes of intermittant use on the batteries and well over 30 minutes of use on the initial 113 bulb.

I must say I'm very impressed so far. The reflector in this light is sputtered and between the smooth beam, the impressive output and relatively small 2C form factor, this is a pretty impressive light.

How many lumens is this mod supposed to put out? It definately seems brighter than the 120 lumens the P61 lamp offers but maybe the much better throw of the Mag just makes it seem brighter.

 

[PlayboyJoeShmoe]

Cool Cratz!

I was outside with my 5AA 2D 4 cell Xenon bulb M*g last night and it had a lazer like quality to the beam. The air was moist enough to see the beam.

I much prefer a nicer quality beam, but this is kinda fun...

 

[cratz2]

So... have you sputtered the reflector? I'll try to take some pictures. It REALLY improves the beam quality.

I do need to pick up one of those 8AA or 6AA to 2D converter things.

 

[cratz2]

Sputtered reflector

3x123 + KPR112 with sputtered reflector at its widest focus

3x123 + KPR112 with sputtered reflector at its narrowest focus

3D Mag with 4 C Cells stock reflector at its narrowest focus

 

[PlayboyJoeShmoe]

I have to get some aluminum reflectors for the really hot stuff.

For normal overdrive like mine, Writeright or Scotch Satin Tape do the job. I just don't have any of my stuff, it all being in storage until we move. I built this with a new M*g 2D and parts I have had shipped since packing up.

Sputtering looks nice, but I doubt it can take much heat!

 

[cratz2]

True... I'm not that progressed yet where I need to worry about heat. /ubbthreads/images/graemlins/grin.gif

 

[vhyper007]

hello cratz,
now I have seen a sputtered reflector but I dont know how you did it. Will you share or is it a trade secret.
Flashoholic in name but still very much a nooby.
Rebards,
Vhyper

 

[bjn70]

You can search for "sputter" and find threads about this. It looks to me like you get some clear spray paint, and spray the reflector from far enough away that you just get individual drops on the reflector and not full coverage. The little individual drops reflect/refract the light differently from the surrounding smooth reflector areas and fill in the weak spots in the beam.

 

[paulr]

KPR113 is for 4 1.5 volt cells or 2x123. For 3x123 you supposedly want a KPR118, though some people overdrive the 112.

I'm using a 118 and it's nice.

 

[cratz2]

I've sputtered about 8 reflectors but not this particular reflector. I can get them to have more of a pebbled finish that has a tighter hotspot, but I prefer this technique which I have not been able to duplicate.

Here are the instructions that were given to me by another forum member, Nikon:

[ QUOTE ]
Use Krylon Crystal Clear Acrylic spray. Don't shake the can before using because you don't want a smooth spray, you want droplets of paint to land on the reflector.

Sputtering is much easier to do when the can is nearly empty than when it's full, but with a little practice you can get the effect you want. Don't push the spray button down very far, and it helps to pull the button backward as you press (it allows better control).

Do all spraying outdoors for the sake of your health. Practice spraying in the air until you can make tiny droplets come from the can without any smooth spray. You should master this very quickly. With a full can you'll only be able to get the droplets to spray about a foot in distance. With a near empty can they'll go much farther.

It should take at least six coats to properly sputter a reflector, and each coat should be very light. Allow fifteen minutes drying time between coats. It's more economical to sputter several reflectors at a time because you have to clear the nozzle of the spray can between each coat and this wastes a lot of the acrylic.

Cover your hand with a plastic bag or something similar and grasp the rear of the reflector, facing the front toward yourself. Hold the spray can the appropriate distance from the reflector and apply the first coat, rotating the reflector to insure even coverage. Spray for a fraction of a second at a time, look at the reflector, and spray more if you obviously missed some spots, but don't overdo it. Set the reflector down to dry and clean the nozzle by inverting the can and spraying until nothing but air comes out.

After you've finished sputtering, allow the reflector to dry at least overnight before putting it in the light. I allow mine to dry for two weeks.

[/ QUOTE ]

My technique is basically the same. I shoot two very short sprays two sprays of the acrylic onto the reflector from about 18 to 24 inches away, sort of catching the droplets on their way down then I let them dry for about 10 minutes then repeat. I do this six times and end up with a finer coverage that allows a smaller and tighter hotspot which work slightly better outdoors at longer distances but again, indoors I prefer the hotspot of the Nikon sputtered reflectors. I also don't clean the nozzle between sprays.

I'll try to take some pictures of his reflectors next to mine.

Edited for clarification and spelling.