Wurkkos

Coil image in beam

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
I recently purchased a 5 cell maglite magnum star bulb. I guess they were still krypton but an upgrade on the whitestar. I popped it in a 3c mag with 2x18650s and even with a OP reflector there's a hole in the center of the beam. But worst is a huge image of a coil in the beam. I tried the bulb in another light ( some 2xAA plastic bodied Energizer light with 2x14500) and same thing. Either of those lights have a good beam with another bulb.
Is this a manufacturing defect? I know Incan mags aren't known for having the best perfectly round beams, but this is pretty bad
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
I don't know what a #222 is But only this bulb does it in three different lights it's been put in. With both SMO and OP reflectors. I have another of the exact same bulb that throws an almost perfect beam
 

Juggernaut

Well-known member
Joined
Feb 18, 2008
Messages
1,485
Location
A place in need of light.
Any smooth mirrored reflector projects an image of the light emitting surface as snakebite said. This is the same for an LED. The thing is an LED is a small flat smooth surface so it projects the same for light. If you use an aspheric lens LED light you'll see a perfect duplicate of the LED for example. The same is true for Icans. The thing with Incans is the complex shape of the tungsten filament often gets scrambled as the light from the coils converge. But sometimes this is not the case. Seeing the filament in an incan projected can be good or bad. Bad if the filament is so bent on its post that it no longer lines up and you get a clear image because you only have a small portion of it actually at the focal plane. Good if your mirrored reflector such as found in parabolic PAR36 and PAR46 bulbs are of high enough quality it projects only a perfect filament and you end up with incredibly focused long throwing light.
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
I wish I could post a picture of it but this website doesn't seem to have a way to add images. And I don't have imgur or anything. But I get around hotspot with an obvious coil straight in the center of it and extends out beyond the edges of the circle of light by quite a bit
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
More than likely as someone else pointed out I probably just got a bad bulb. Being at my other one looks perfect. Maybe I will try frosting it as I've never done that before
 

fivemega

Well-known member
CPF Supporter
Joined
Jan 28, 2003
Messages
5,124
Location
California
I recently purchased a 5 cell maglite magnum star bulb. I popped it in a 3c mag with 2x18650s and even with a OP reflector there's a hole in the center of the beam. But worst is a huge image of a coil in the beam.
Turn on the light and try to focus it best possile. Turn off and don't change focusing.
While light is off, look at bulb and reflector from straight front of flashlight and check if bulb and it's fillament is centered. Bi pin bulbs can be centered but PR base can not.
You can also change your reflector from LOP to MOP or even HOP.
Another choice is applying
Armor Etch for 5 minutes and recheck. If it works but not good enough, then try 10 minutes.
Another thing may cause on center dark hole is size of reflector hole which should be slightly larger than bulb diameter.
There is no reason to use reflector opening of say 15mm for bulb diameter of 8mm. and in this case:
1- Part of light is wasted / not reflected and goes underneath of reflector without any benefit.
2- Diameter of dark hole on reflected beam will be bigger, uglier and less usefull.
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
Thanks FM. Bulb and filament look centered. The hole in reflector is only big enough to just let the bulb through. I could etch it but for a $2 bulb? I'll probably just use it until it burns out or I replace it. It's in a light I don't care that much about using
 

fivemega

Well-known member
CPF Supporter
Joined
Jan 28, 2003
Messages
5,124
Location
California
Any diffusion of the beam decreases output.
Let's make some correction:
Any diffusion of the beam decreases hotspot output.
In fact decreased part of light from hotspot is redirected to somewhere else which we didn't want to but no other choice.
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
I sanded the bulb with some 400 sic paper. Then smoothed out with some 600 grit. From using in my darkened shed it appears
I've fixed the problem. The donut hole is mostly gone and I can no longer see the filament. I will have to confirm when I take the dog for a walk this evening.
I'm surprised these trustfire 14500s from ~8 years ago are still working. Not getting hot or anything and holding voltage. I've had to throw one away but the rest are still doing well
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
Ok so that light sanding worked. The light is throwing a nice beam now. Not much throw but it is a small reflector. Similar beam and output to a d26 LA. Not bad for a couple 14500s I had sitting around and a $3 bulb
 

snakebite

Well-known member
Joined
Mar 17, 2001
Messages
2,549
Location
dayton oh
watch for melting in that cheap plastic light.
few cheapies will stand up to a 5 cell xenon and 2 14500.
if its not the reflector melting its the bulb holder area.
 

vicv

Well-known member
Joined
Mar 22, 2013
Messages
1,250
Location
Southern Ontario
Yes I will watch out for that. I'm only using it briefly. And once something goes wrong on at the light will probably be tossed as it's just something I found and I'm playing with
 

LuxLuthor

Well-known member
Joined
Nov 5, 2005
Messages
10,409
Location
CT
Let's make some correction:
Any diffusion of the beam decreases hotspot output.
In fact decreased part of light from hotspot is redirected to somewhere else which we didn't want to but no other choice.

I am always amazed at how brilliant and knowledgeable, Fivemega is.
 
Top