Light Cannon - my head won`t come off!

LEDBE
Chris M.

Chris M.

Flashlight Enthusiast
Joined
Jan 17, 2001
Messages
2,564
Location
South Wales, UK
I`m just finishing off my review of this otherwise fine light, when I go to take its head off in order to grab one last photo of its insides. And I`m turning and turning, and the head won`t budge. Using the handle as a brace to aid my grip was futile, as the handle broke away - I was turning that hard. Clamping the body in a bench vice was the last resort - and still, it won`t come off. I`ve turned so hard that my hands are sore. I don`t know how I`m going to get the thing off. Needless to say, all this is now in the review, and that picture I wanted of the shock isolating stuff round the bulb holder is not.

Has anyone else experienced this? It would appear that the o-ring and possibly the threads are causing the stickage. It was cleaned and lubed only 3 weeks ago and I was sure I didn`t put too much on. I used SuperLube, which is supposed to be perfectly OK.

This is very frustrating! I`ll try again later to get the top off but in the meantime I`d welcome hearing from anyone else who`s had this trouble. So I know I`m not alone....

/ubbthreads/images/graemlins/icon15.gif /ubbthreads/images/graemlins/icon23.gif
 
OK, I finally got it off. Had to roll a towel up so it was all thin, then wrap that round the head really tight so`s I could get a better grip, then grab hold of the free end, pull and turn, and eventually the rubber bit quit turning all by itsself and the head slowly came free. Being clamped in that bench-vice has messed up the stickers on each side, but I`ll admit I never cared for those so this is as good an excuse as any to peel them off completely. I think the handle will be OK too, just got to be a bit careful with it and watch that it doesn`t get too loose.

I`ve cleaned off all but the slightest trace of lube from the threads and o-ring as I suspect there was a little too much on there after all. And taken that picture of course. Just hope it won`t stick solid like the last time - I havn`t tightened the head to what I`d consider too tight, but we`ll see.

Still would be interested to know if this is an isolated problem or one that crops up quite often.

Expect the review to be published later tonight. It`s as good as done, just wants proof-reading....

/ubbthreads/images/graemlins/ooo.gif /ubbthreads/images/graemlins/grin.gif
 
I do know from my airgun days that certain lubes (not familiar w/SuperLube) will melt/deform/breakdown o-rings and other rubber/plastic parts, causing them to stick and in worst-case scenarios, actually fuse to other synthetic parts; WD-40 is mentioned as one particularly aggressive example.
 
I used the Sta-Lube white lithium grease on my Trek 6000 EX60. And now its head also won't come off. For 4 months now, it's stuck like that, and I'm also afraid of maimin' the body by clampin' it down...

I think there's just some lubs, like lithium grease or molybdenum grease that if you apply too much to a plastic thread or joint, you risk caking and hardening it. And because the threads on the Light Cannon and EX60 are plastic instead of metal, I'm assuming that's part of the reason the lube will harden and cake.

I've never had a problem with clear silicon lubes, but the lithium greases are starting to frustrate me. I'll never touch them again. Heck, even synthetic automotive motor oil's better at lubing than lithium is...
 
Chris,

This is what PK told me about nygel (silcone)

Any silicon base works fine. The problem is the petro chemical base lubricants cause rubber o-rings to swell
 
Thanks for the replies.

So, does this mean Superlube is petrochemical-based? They claim it`s universal, so I remember. At Least I didn`t pay for it (freebie sample). I`ll admit I have had less than desirable results with it on my Tektite lights too - the heads becoming very stiff.

I`ll have to try and track me down some silicone lube and see if I don`t have better luck with that....

/ubbthreads/images/graemlins/grin.gif
 
Thanks for the link - I thought as much. /ubbthreads/images/graemlins/grin.gif

Teflon-based, now that *should* be OK with my o-rings, shouldn`t it? But apparently not, based on what happened to my Light Cannon and to a lesser degree, the Tektite Expedition LED lights.

/ubbthreads/images/graemlins/confused.gif
 
Maybe it's not the lube?
I had a similar problem with a Lightwave 4000, it just seems to have threads that locked tight if the head was screwed on tightly..just guessing tho' ..
 
Very possibly. My LW4000 suffers a similar problem if overtightened and that one hasn`t been near the Superlube.

Kind of why I started this topic - to see if anyone else had ever been locked out of their Light Cannon for any reason. Think of it as post-review research! Once I gather more "evidence" as to whether it`s a potential design flaw like the LW4000 or whether it was something I did, I`ll post an update and maybe alter the ratings up or down accordingly. It`s been marked down on reliability for now cos if I can`t open it when the batteries need changing, I can`t really rely on it in important situations.

/ubbthreads/images/graemlins/wink.gif
 
Hi Chris

Among divers, the primary targets of the Light Cannon, it is a rule never to use anything but silicone grease to lubricate o-rings. You will be able to get it at a dive shop (but not cheaply!).

The UK lights are common among divers, and I've seen several cases where it took a concerted effort by a strong guy to open them (mostly UK400's, the precursor for the D4, but I would think the construction is similar). This was the kind where the handle was part of the housing and strong enough to be used as a lever.

It is very important to lube the treads and o-ring. Also the bezel should only be tightened enough to compress the o-ring, not so much that it is pressed hard against the body. This assumes that the seal design is the same in the UK400 and Light Cannon (which I have never seen).

Hope this helps
Jesper
 
Oh - and another thing:

Quote from review:
"Possibly the most technologically advanced diving light on the market ...."

The Light Cannon is very far from being the most technologically advanced dive light on the market. No, for this, take a look at german dive lights! /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif

Jesper
 
Thanks - that is very helpful. I`ll update the review this weekend when I get the time, and I`ll be sure to add that reccomendation.

As for my "technologically advanced" comment - that was referring to the metal-halide light source. I was under the impression that it was the first one to the market that used such a thing. But you`ve got me interested now - know any sites that give good details of some of these German lights you mention? I`m not a diver but the technology fascinates me.

Perhaps if I changed it to "one of the most...." - would that be more accurate?

/ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/grin.gif
 
Falcon- Send your 6000 back to us, we'll repair it.

For plastic: Parker Super O-lube, or Dow 111 are the only ones we recommend. We use Parker in our Mfg. process. We have .1 oz tubes available, $1.00 each.

Chris M- Your Light Cannon head probably stuck due to a change in pressure or temperature. Large bezel sealed lights are prone to "lock-up" if the inside pressure is lower than the outside (ie: closing it up on a rainy day, or higher elevation). I saw a LOT of this with UK lights back when I was a UK dealer. We usually used a padded chain vise to get the bezels off the old UK 600 & 1200's /ubbthreads/images/graemlins/naughty.gif
 
FalconFX,

I just wanted to tell you that i have the same problem with my Light Cannon from time to time. I have NO idea what it is. It is as if the threads are fusing together. I have used a silicone based grease that i found at a hardware store. I applied it to both the orings and the threads - It doesn't help any.

I always have to sit the light inbetween my legs and grip the head REALLY tight and TURN. Actually, i'm trying to open it up RIGHT NOW. It's taking quite a bit of effor to unscrew the head.

Sorry, i have no answers, but i just want to let you know that you aren't the only one experiencing this with the Light Cannon.
 
Thanks LEDagent...

I've tried everything from a crankshaft and rubber hosings to near ripping off the handle to open it up. My cousin's a 265lbs wrestler, and if HE couldn't get it open, I don't know what will, besides putting so much force on it that it breaks... That's why it's going to get shipped back to Tektite later on this week for some treatment...
 
JESPER, These are both silicone base. Parker is a heavy oil, Dow is a grease. They both work well for plastic o-ring glands.

ALL- bear in mind that all o-rings are not alike. There are several different compounds. Silicone lube seems to work with all.

For the light cannon bezel problem- Try putting the light in a bath of warm (90 deg F)water for 45 min. Remember P=V/T /ubbthreads/images/graemlins/icon6.gif
 
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