A lightbulb moment, but...

[Cozzer]

Had a kitchen lightbulb pop last night, so fitted a new one.
Bayonet fitting, 60w candle. Push in, turn, flick switch, all is good.
Less than 5 minutes later, it dulled for a couple of seconds, and then went out.
Got another spare ready, mounted the steps, pushed up and turned the dud bulb...except it wouldn't turn.
Gripped the top of the unit, pushed up and turned. Pushed up yes, turn no.
Back to the TV football - I'll do it in daylight tomorrow.
This morning, no way would that bulb come out. Again, I could push up, but not turn.
I ended up smashing the bulb, leaving the metal base inserted in the holder.
Pliers it is, then.
You can see the result in the photo. I had to mangle it completely in order to get the thing's terminals to twist and eventually free.
When I inspected it, the bottom of the metal base had a varnish - adhesive? - covering, which had apparently melted and in effect glued itself to the holder.
In fact, if you look at the bottom left photo, you can actually see a dent in one of the terminals. So soft, it had melted.
We happen to have bought half-a-dozen of these bulbs - from a reputable seller - so I checked another one. Bottom right pic, You can clearly see "globs" of whatever it is around the two terminals...
I'm not going to buy any more, and I'd seriously advise you to do the same...

 

[clogs]

nasty...Chinese made.......??
can't remeber the last time I changed a bayonet fitting bulb......
did have a years old bulb that melted the terms once......
had to shorten the wires by cutting off the fitting....lol.....
what other part of the world uses these fittings....??

 

[flying haggis]

The "varnish" is probably flux used when they solder the contacts on the base

 

[Cozzer]

nasty...Chinese made.......??
can't remeber the last time I changed a bayonet fitting bulb......
did have a years old bulb that melted the terms once......
had to shorten the wires by cutting off the fitting....lol.....
what other part of the world uses these fittings....??

I'm guessing Chinese, yes.
I've just checked one of the others - unused, straight out of the box, I can actually turn the glass bit whilst holding the metal base!
Never struck me before, but how is the bulb normally "fixed" to the base? Glued? Glued and crimped?
Either way, I'm sure you shouldn't be able to spin it!

 

[clogs]

Cozzer...
glued with some kind of resin.....remember it also has to be heatproof......

I think even the known brands have their standards lowered....

watched a doc about Osram or Phillips developing a special high powered LED for the Soudis.....
they cant sell the tech anywhere else for 5 years....
it was called something like the Soudi LED......

out of interest found the doc.....
https://hackaday.com/2021/01/17/leds-from-dubai-the-royal-lights-you-cant-buy/

 

[Cozzer]

...And the new bulb, fitted this morning?

It just failed.
It least I can get it out this time, but it rattles....so....blown.

 

[Phil Pascoe]

A lightbulb moment, but ...
aren't 60w lightbulbs long obsolete?

 

[Cozzer]

A lightbulb moment, but ...
aren't 60w lightbulbs long obsolete?

In what respect?
You can still buy 'em!

 

[Phil Pascoe]

You can still buy mammoth tusks.

 

[baldkev]

If you tried a more known / respectable brand and it pops, you might need a sparky to test the wiring?

 

[Fergie 307]

Get a decent quality led one, safe yourself some sggro, and money!

 

[Oldman]

Why are you not using candle LED bulbs with 6watts of energy used for 60watts worth of light?

 

[Cozzer]

Why are you not using candle LED bulbs with 6watts of energy used for 60watts worth of light?

Got one or two around the house, but only in rooms where we don't spend much time.
Prefer not to use 'em because of the really high pitched sound that they emit. It's the same with the 12v system that's in the bathroom...been threatening to pull that out for some time.

 

[Ttrees]

Got one or two around the house, but only in rooms where we don't spend much time.
Prefer not to use 'em because of the really high pitched sound that they emit. It's the same with the 12v system that's in the bathroom...been threatening to pull that out for some time.

Can't say I've noticed high pitched noise coming from my lamp.
Just to be clear, this is the type(ish) of bulb I have been using.
I haven't happened across cheap versions of these bulbs with the plastic (necks?)
and think mine is also Phillips.

It's used in one of those angle poise lamps with no earth,
so perhaps this has something to do with it.

Having being converted to these now, they seem to take a knock better than the cheapie incandescent types,
and most importantly the lighting has the same warmth to them, lumen-wise,
but perhaps not so temperature wise for those with no heating.

CRI, or whatever ya call it, is important on the angle poise glare-wise

or for others who simply want warmer colour.
These type superbright LED you cannot use for close up tasks,
as will cause glare blindness, aswell as having terrible CRI qualities.
1224 × 711
My Claas seed green painted stuff, appears as an ii-luminous horrible colour compared to what it looks outside in the sun.
(explains why I thought there were differing shades of the same RAL colour,
and that I need more yellow in the paint to get an outside Claas green colour in the shed)
The new obsolete florescent tubes which I bought aren't as warm, seems brighter greens might be the most "difficult" colour to get what one wants.
It makes it quite apparent, which maybe a good thing,
warmer light having less glare, and better for matching various shades of timbers
for a project.


Another thing regarding these bayonet cap bulbs is the sockets.
I'm not sure of this, so someone will likely confirm,
but I have heard it said that one must not insert these into the fitting with excessive force, as the L&N in some fittings aren't sprung brass parts, but rather a bit of bent sheet, which can deform causing an ark between terminal and bulb,
which melts the bottom.

I guess this is the case even with these economic bulbs too?

 

[flying haggis]

anglepoise with no earth will not affect the bulb. I buy all my led bulbs from poundland and have done for years, I have had their bulbs for five + years and have only had to replace one.
Even got some new old stock dimmable GU10 bulbs from the local car boot for 10p each still in boxes. As i sit and type this we have nine poundland bulbs on at present, a mixture of 3 and 5 watt ones and I dont think they are in any way inferior to incandescent bulbs and save money as well. My neighbour was sceptical about led bulbs and his wife didnt like that the ones I got them didnt have the little bent tip like a flame that the old ones had! But when I asked if they would prefer to run the four lights in the lounge for one evening or use leds and run the four bulbs for 13 evenings for the same cost the lack of bent tip didnt matter so much...

dont think I have seen BC fittings with bent metal contacts before but you do have to push the bulb down to get the pins to latch so the metal must be springy enough to cope. led bulbs run at less current than normal bulbs approx 1/10 and also put out a lot less heat so are better for the fitting all round

 

[Thingybob]

Been LED in my last house and changed all the ones in the new house as soon as we moved in and only had one bad one in 7 years and that one blew with a pop and you've guessed it cheapo rubbish from China missus bought from Home Bargains other than that not had to replace any other bulbs in 7 years

 

[Phil Pascoe]

Similar. We moved 12/13 and the first thing I did was change ever bulb in the house. We've moved again since and I did the same. Mostly cheap ones and I've had one fail in all that time.

 

[Lons]

I've just done a quick count and we have 44 various style LED bulbs installed plus several LED table lamps and outside security lights and have only changed 3 or 4 bulbs from memory over the years. Most of the bulbs are 5 watt, warm white are instant light apart from 3 very old ones of different type which take a few seconds to warm up and none of them produce a noticeable high pitched noise. Technology has moved on a pace since the early bulbs but you need to buy quality or you'll get what you pay for.

My study which I use a lot has 6 GU10 bulbs previously 50 watts each so total 300 watts which now with LED totals only 30 watts and that's just one room, surely that makes sense?
I have 2 cardboard boxes in the loft full of incandescent bulbs which will never be used.

 

[Phil Pascoe]

I'm surprised the government hasn't subsidised the sales of LEDs as it did with CFLs.

 

[imageel]

I did a lot of research before building my own lighting replacement system since there are so many factors involved and it gets quite complicated when you start to consider the required lighting levels you want and say compare those with published levels required for say detailed work like jewellery or surgery.
For starters the CRI or colour rendition index of led sources has improved greatly over the years, and these days most high CRI >80 sources use deep blue- near UV leds to cause a phosphorescent coating to emit a near-even light spectrum, these tend to also maintain better colour balance when dimmed especially over the older 'white' leds that comprise RGB colours.
One of the challenges with task lighting, as others have alluded, is that having sufficient illumination without glare can sometimes be difficult to achieve, and this usually is dependent upon the reflectivity of the object you are viewing which in context varies quite a lot - rough sawn versus planed etc.
The conclusions that I have arrived at are -
CRI - this determines how true to colour objects will appear under artificial light versus natural
Colour temperature - natural daylight is nearer 4000K than the traditional 3500K, which more mimics the light produced by candles or spirit lamps
...but most importantly -
Achieving an even light distribution is far more important than the actual overall light density achieved - this is usually quoted in lux.

e.g. in my study where I do most of my IT/electronics work I have 4 LED uplighters mounted high up in each corner reflecting light off the white emulsioned ceiling and whilst the overall lighting level barely reaches 500lux, because it is very dispersed, there are few shadows cast by any object, and hence the perceived edge contrast is very high.
In short everything appears a lot sharper and distinct even thought the actual lux levels are orders of magnitude lower than 'industry standards' would dictate.
Put it this way with 500lux evenly distributed I could get down on all fours and do needlework or fine electronic work (my working limit with glasses is about 0.1mm) in any part of the floor, corners included!