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View Full Version : Is there a secret to those fluorescent tube shields?



J Tiers
12-27-2012, 11:42 PM
The clear plastic pipe with end caps that somewhat protect the tubes...... I came across several sets of them in 4', and decided they might be a good idea, since a time or two something has hit the tubes in my lights, although they have never broken.

I fought several of them onto the lights over the bench and 3 machines tonight, but the end caps defeated me totally. I ended up putting the clear pipe on only, figuring it is better than nothing, even though it leaves 0.75 inch or so uncovered.

My problem was that with the complete cover in place, I could not grip the tube, and it could not be forced to turn and lock in place. Perhaps they are only for the snap-in type, not the 4 pin type that fits into a slotted connector and is turned to lock.

But I HAVE seen them in place on regular turn-to-lock type lamps. In fact I got these off bad tubes of the 4 pin type. However, these have round holes in the end caps.... perhaps the 4 pin type should have a slot?

What's the secret to turning a slippery glass tube that is totally covered by slippery plastic?

RussZHC
12-28-2012, 12:02 AM
They can be a real PITA, there is one set at work I just dread doing, all the others are OK though. I think a large part of the reason that one set is difficult is there are actually fixtures end to end and whomever installed them either screwed or riveted them so there is no give and with all other fixtures they are alone and just that little bit of flex is enough to make it work (the "socket" as some small amount of give in the direction the bulbs/lamps fit).
I have never seen the caps with round holes all of the ones we have ever had are slotted.
Not quite sure what I should say about the plastic tube itself any of the ones we have ever had have been flexible enough that you can still grab the glass tube. We change the plastic tubes about once every 12 to 18 months as they do yellow a bit with age depending on where they are (here in a public service food area the bulbs must be covered in such a manner and if they are missing end caps it gets noted as a change that must happen for the re-inspection) and I could see them becoming a bit hard enough with age or contamination (from cooking fumes say) to make it tough to grab the inner bulb.

Sounds a bit silly but is it possible the black end caps were not entirely on? Ours have a bit of a raised "lip" about an 1/8" in from the end pushed into the plastic tube but you also have to be sure the bulb is sitting as far into that black end cap as possible since they can get a bit "hung up" and that can be enough that the pins do not protrude far enough into the "socket".
On those PITA ones I have trimmed both the plastic sleeve and the black end cap, but sometimes they just seem to fit better than others

armedandsafe
12-28-2012, 12:08 AM
I've only fiddled with them once, but two sided tape came in real handy then.

Pops

J Tiers
12-28-2012, 12:12 AM
I've only fiddled with them once, but two sided tape came in real handy then.

Pops

Now THAT is a darn good idea..... I wonder why it never occurred to me?

if we had a "like" button on this forum, that would get a press for sure.....

browne92
12-28-2012, 12:18 AM
The electrician at the hospital I worked at got so tired of fighting them, he bought bulbs that were 'shrink wrapped' with a clear plastic. No idea of cost difference.

armedandsafe
12-28-2012, 12:39 AM
Now THAT is a darn good idea..... I wonder why it never occurred to me?

if we had a "like" button on this forum, that would get a press for sure.....

Keep in mind that the ones I had were new, so they would squish a little when you put pressure on them. That opened a little gap into which to insert the tape. Or to slide over the tape which was already on the bulb. I tried it both ways and it is a bit fussy-fussy either way, but got the job done. Older ones might not be as flexible.

Pops

darryl
12-28-2012, 12:56 AM
Perhaps some contact lube on the pins would help ease the problem of rotating them into proper position. Cramolin made such a product- MG probably does.

lakeside53
12-28-2012, 01:04 AM
I hated them covering the T12 tubes I had, but the T8 covers and ends I bought at Home Depot gave me no problems at all. They fitted the tube a lot tighter than the T12's and the ends were better formed.

macona
12-28-2012, 05:02 AM
I have installed hundreds of them. The trick is just squeeze the plastic tube against the lamp and twist. You wont crack the plastic, it is polycarbonate.

The lamps with the built on plastic shrunk are called "coverguard", at least that is what the GE trademark is. They used to be something like $7 or $8 a pop. They are very durable. Sometime when a lamp with a regular plastic tube cover breaks they whole thing falls from the ceiling spreading glass everywhere, this does not happen with the coverguard ones, they keep everything contained.

Plastic tube covers are also good for lamps that run in cold temperature environments, they add an insulating layer that helps the lamps warm up to temp and full brightness. Especially with T8 lamps with electronic ballasts.

J Tiers
12-28-2012, 09:50 AM
Ja... these are T12.... It isn't a lube issue, it's just the torque to do the "snap".....

I suspect the round hole type are not really made for these.... a slot would work great, as it would apply pressure to the pins, and let a grip on the end turn the tube. So would carpet tape.

Squeezing the outer tube is not that effective.... the outer tube doesn't really have much friction against glass unless you really squeeze.... and the combination of holding heavy pressure while also trying to feel the pins rotating into position.... well it isn't a great ergonomic proposition..... and yes I CAN walk and chew gum at once... but I don't like to chew gum anytime....

The tubes will probably function fine without the ends.... what I wanted was something to somewhat protect the tubes from impacts. Doesn't have to be perfect.

vpt
12-28-2012, 09:58 AM
My parents have those in a 3 door pepsi cooler. However the 4 pin bulbs push into their receptacles (spring loaded) instead of twist. I have also used them on the twist type fixtures but normally they had the correct 2 hole caps for the end of the bulbs so once all together the shield tube was kind of locked to the ends of the bulb.

J Tiers
12-28-2012, 09:40 PM
I have also used them on the twist type fixtures but normally they had the correct 2 hole caps for the end of the bulbs so once all together the shield tube was kind of locked to the ends of the bulb.

HAH....... Didn't know about the two-hole type.....but it makes sense. Of course that would make it somewhat trivial to install them.

I'll bet these are for the snap-in type with one big "button contact" on each end. I don't even know if those are made anymore.

lakeside53
12-28-2012, 09:54 PM
Mine have a slot - does the same thing.

macona
12-29-2012, 04:32 AM
The big hole ones are for slimline or HO lamps with a plunger style tombstone, the ones with an oval hole are for bi-pin lamps.

Putting the lamps in can be difficult at first, it just takes practice.

J Tiers
12-29-2012, 11:29 AM
Si.....easy with the correct type, which evidently these are not.....

is your "plunger style tombstone" the type for the tubes with a single bump-style contact on the end? That's what these would fit, certainly, despite being taken off of bi-pin lamps. I've never dealt with those bump-type tubes (snap-in button type, I called them above), thought they were from the 1940's and long gone now.

ogre
12-29-2012, 03:31 PM
I left mine off also:(

macona
12-29-2012, 10:03 PM
Slimline lamps still exist and are available in T8 too. They are almost exclusively used in commercial locations, the ballasts had a higher noise output than generic bi-pin lamps. There are also HO lamps which use a recessed bi-pin socket that is a plunger type as well.

Slimline works well, still. They now use electronic ballasts.