SF Bulb Transplant

[larryk]

Has anyone tried to replace the bulb on a Surefire LA. I'm referring to the LA's for the M3 and other Turbo head LA's. I have seen that someone has done this with a LED transplant.

 

[wquiles]

You mean with something like this?

I was able to get one of the LED adapters sometime back and I am about to use one of my WX1T's and a 1000mA downboy to make my own module.

I am not sure who else makes these - looks like all of them are hand made/custom jobbies /ubbthreads/images/graemlins/grin.gif

Will

 

[larryk]

Not exactly, I was thinking more on the lines of transplanting a WA 1185 bulb in one.

 

[js]

larryk,

It could be done, and is something I've thought about--I even got a burnt out SF lamp from Britt for free for this purpose--but there are two problems, or actually three for most people:

1. You need a good ceramic potting compound, such as the Cotronics 940 LE.

2. You need to get the filament not only centered, but also at the right height, because there is no room for focusing adjustment; the collar hits the back of the reflector and wherever that filament is, that's where it will stay. With the ring-potted lamps I make, you get to move them in and out and then tighten a set screw. Not so with the double spring SF LA's.

3. The leads from the lamp must be quite long--longer than they are--in order to be soldered to the appropriate places on the double coil springs of the LA. You could run jumper wires, but I'm pretty sure that the ends of the lamp leads on an 1185 get way too hot for even the higher temp solders. You could braze some jumper wires on, I suppose.

Anyway, it's an idea with potential, but it's certainly going to be labor intensive and difficult.

 

[larryk]

Hi Jim, I know this would be tricky, but how about putting a small bi-pin socket on the LA ? That way you would have more options for changing to different bulbs. As far as focusing, couldn't you error a little and place the focal point a little forward and use a shim or shims to compensate ?

 

[Luna]

[ QUOTE ]
the lamp leads on an 1185 get way too hot for even the higher temp solders. You could braze some jumper wires on, I suppose.

[/ QUOTE ]

I believe you have to weld the moly wire.

 

[js]

Larry,

Yes. I actually thought of doing these very things! Neat. But ultimately, a socket is a less than great solution. I mean, certainly it's a cheaper way to go on a per bulb basis, but having the filament constantly working off center is a real anoyance in my book. I'll pay the extra money or take the extra trouble to have a ring-potted lamp or a SF LA type setup.

Luna,

I have no idea myself if there are any brazes that would work with molybdenum, but it's certainly possible that there aren't. This wouldn't surprise me at all.

 

[paulr]

Js, have you used a Streamlight TL2 or TL3? The rotating bezel lets you adjust the height, more or less. Normally it's only necessary to do that once with each bulb, immediately after installing it.

 

[js]

paulr,

I've never used any of the SL TL's, only the SL TT 2L. This sounds good, but if the TL's have a socket and take bare bi-pin lamps, then they will still wander off-center. I never said they wander off-focus, but only off-center. At least in my expierence with the MC they do. Perhaps the TL's are different.