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Adapting white LEDs as festoon bulbs?

N

N Cook

Jan 1, 1970
0
Where 5mm is the maximum dimension / available space of the original bulb so
you cannot turn aroud the LED. Would be useful for replacing awkward voltage
festoon bulbs.
The maximum beam of 5mm LEDs is axially but how to convert to transverse?
Grind an angle to the dome and melt on some mylar?
Wrap whole LED in mylar except for an axial slot?
Abraid the LED all round to make translucent rather than clear?

Then adapting AC or DC supply to suit
 
D

Dave Plowman (News)

Jan 1, 1970
0
Where 5mm is the maximum dimension / available space of the original
bulb so you cannot turn aroud the LED. Would be useful for replacing
awkward voltage festoon bulbs. The maximum beam of 5mm LEDs is axially
but how to convert to transverse? Grind an angle to the dome and melt on
some mylar? Wrap whole LED in mylar except for an axial slot? Abraid the
LED all round to make translucent rather than clear?

Are you restricted to 5mm types? There are also very short ones available.

Problem with LEDs is the diabolical 'colour' if used as a replacement for
tungsten. Which may not matter, of course.
 
R

Ron(UK)

Jan 1, 1970
0
N said:
Where 5mm is the maximum dimension / available space of the original bulb so
you cannot turn aroud the LED. Would be useful for replacing awkward voltage
festoon bulbs.
The maximum beam of 5mm LEDs is axially but how to convert to transverse?
Grind an angle to the dome and melt on some mylar?
Wrap whole LED in mylar except for an axial slot?
Abraid the LED all round to make translucent rather than clear?

Then adapting AC or DC supply to suit

You can buy 12v led festoon bulbs, Google for led car accessories.

Ron
 
T

Trevor Wilson

Jan 1, 1970
0
N Cook said:
Where 5mm is the maximum dimension / available space of the original bulb
so
you cannot turn aroud the LED. Would be useful for replacing awkward
voltage
festoon bulbs.

**Nonsense. LEDs are available in a wide variety of shapes and sizes. Many
are much smaller than 5mm.
The maximum beam of 5mm LEDs is axially but how to convert to transverse?

**Again, wrong. Lumiled (and others) manufacture LEDs with a 120o (or more)
light spread.
Grind an angle to the dome and melt on some mylar?
Wrap whole LED in mylar except for an axial slot?
Abraid the LED all round to make translucent rather than clear?

Then adapting AC or DC supply to suit

**Try not to re-invent the wheel. Look at the alternatives. They are easy
enough to find.

Trevor Wilson
 
J

James Sweet

Jan 1, 1970
0
N Cook said:
Where 5mm is the maximum dimension / available space of the original bulb
so
you cannot turn aroud the LED. Would be useful for replacing awkward
voltage
festoon bulbs.
The maximum beam of 5mm LEDs is axially but how to convert to transverse?
Grind an angle to the dome and melt on some mylar?
Wrap whole LED in mylar except for an axial slot?
Abraid the LED all round to make translucent rather than clear?

Then adapting AC or DC supply to suit


While I've built LED replacements in a pinch, this is one of those things
where it makes more sense to buy a ready made LED retrofit lamp than to try
to build something, unless maybe you already have a bunch of LEDs you want
to put to use.
 
N

N Cook

Jan 1, 1970
0
James Sweet said:
While I've built LED replacements in a pinch, this is one of those things
where it makes more sense to buy a ready made LED retrofit lamp than to try
to build something, unless maybe you already have a bunch of LEDs you want
to put to use.

I have 27 salvaged 35mA ,5mm white o/p LEDs and no 3mm, and every now and
then need a festoon bulb that is usually not 12V.

The bluishness can be compensated for to a certain extent by coating with
varnish with a tiny spot of red dye mixed in.

So far the best conversion seems to be 1.25 inch fuse glass barrel with ends
removed, scored and cut down to size , heated and pushed over an LED and an
oval of muylar glued into the open end, forming a 45 degree or so mirror.
Placing back the fuse ends for soldering to, with wires taken external to
the barrel..
Then a wash of vaguely red tinted varnish over the glass.
 
D

Deke

Jan 1, 1970
0
N Cook said:
Where 5mm is the maximum dimension / available space of the original bulb so
you cannot turn aroud the LED. Would be useful for replacing awkward voltage
festoon bulbs.
The maximum beam of 5mm LEDs is axially but how to convert to transverse?
Grind an angle to the dome and melt on some mylar?
Wrap whole LED in mylar except for an axial slot?
Abraid the LED all round to make translucent rather than clear?

Then adapting AC or DC supply to suit
Question...what the heck is a "festoon", and why does it need bulbs? Are we
talking outdoor lighting?
 
J

James Sweet

Jan 1, 1970
0
Question...what the heck is a "festoon", and why does it need bulbs? Are
we
talking outdoor lighting?

Double ended tubular bulbs, I think it's primarily British terminology. Many
automotive dome lights use them.
 
M

Michael Kennedy

Jan 1, 1970
0
James Sweet said:
Double ended tubular bulbs, I think it's primarily British terminology.
Many automotive dome lights use them.

OH. Ok.. The dictonary wasn't helping because the defition for festoon is
either festive deocoration or feast.
 
D

Dave Plowman (News)

Jan 1, 1970
0
You can buy 12v led festoon bulbs, Google for led car accessories.

The ones I've seen are of a larger diameter than a 6 watt festoon type.
10mm seems to be the common diameter - so a replacement for 10/18w types.
I suspect by the text it's the smaller one Mr Cook wants to replace -
meter lights etc?
 
R

Ron(UK)

Jan 1, 1970
0
N said:
I have 27 salvaged 35mA ,5mm white o/p LEDs and no 3mm, and every now and
then need a festoon bulb that is usually not 12V.

The bluishness can be compensated for to a certain extent by coating with
varnish with a tiny spot of red dye mixed in.

So far the best conversion seems to be 1.25 inch fuse glass barrel with ends
removed, scored and cut down to size , heated and pushed over an LED and an
oval of muylar glued into the open end, forming a 45 degree or so mirror.
Placing back the fuse ends for soldering to, with wires taken external to
the barrel..
Then a wash of vaguely red tinted varnish over the glass.


Or you could spend £1.99 and buy one with three white leds ready made.
 
N

N Cook

Jan 1, 1970
0
Dave Plowman (News) said:
The ones I've seen are of a larger diameter than a 6 watt festoon type.
10mm seems to be the common diameter - so a replacement for 10/18w types.
I suspect by the text it's the smaller one Mr Cook wants to replace -
meter lights etc?

--
*Funny, I don't remember being absent minded.

Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

With the larger ones there is no great problem finding some sort of filament
bulb to replace it with.
But small diameter , high wattage ones, like the those built into meters are
a different matter.
3mm LEDs, in there, would give a spot light which would not be distributed
by the white plastic housing, giving a very poor meter illumination

I've never tried melting an LED before , not that easy.

In the process I found that filling the glass barrel with translucent hot
melt glue gives quite a good linear diffused illumination.
Air entrained clear glue or plastic would probably be a bit better but
hot-melt is quite convenient.

Domelamp =USA= barrel filament bulb, or the automotive housing where they
are found ?
 
N

N Cook

Jan 1, 1970
0
The point of a festoon bulb, or the wire-ended ones, is you can put in a lot
of wattage, get out a lot of illumination, by using a package that is quite
large in one dimension, only, unlike having to expand all 3 dimensions of a
globe bulb.
 
N

N Cook

Jan 1, 1970
0
Comparison of 2 in series
http://home.graffiti.net/diverse:graffiti.net/festoon_LED.jpg
as original LED and then a half length, 1 1/4 inch fuse barrel filled with
hot-melt glue.

A bit more scientifically measuring the original transverse, at a given
distance over matt black carbon/foam , was about 30 lux, modified LED about
180 lux and for comparison a 12V 6W festoon lamp at the same distance about
1000 lux.

Comparison of illumination , by readable text, at a distance of a foot I
would say the modified LED was equivalent to the 12V bulb running at 0.1
amps rather than 0.2A.
So at least 2 such LEDs at 30mA to have any chance of equalling the
illumination of the festoon.
So a white LED at each end of a filled glass barrel , at least , needed to
equal.

The mylar mirror just gave 2 bright spots rather than an illuminator, but
"frosting" of the glass may still work
 
G

GregS

Jan 1, 1970
0
I have 27 salvaged 35mA ,5mm white o/p LEDs and no 3mm, and every now and
then need a festoon bulb that is usually not 12V.

The bluishness can be compensated for to a certain extent by coating with
varnish with a tiny spot of red dye mixed in.

I used to have the paints for coating lamps or glass from craft stores.
I'll have to try your mixture for led's. Warm white led's are becomming more
common, and are required for illumination of different things in the home.
My current need is making under cabinet kitchen lamps.

greg
 
N

N Cook

Jan 1, 1970
0
msg said:
Cartridge Lamp

Michael

Not according to Goofle/images
"Cartridge Lamp"
79 hits , only 1 in first 2 pages that I would call a festoon bulb

put "festoon bulb", 477 hits
in google/images and first page is nearly full of them
 
R

Ron(UK)

Jan 1, 1970
0
N said:
Not according to Goofle/images
"Cartridge Lamp"
79 hits , only 1 in first 2 pages that I would call a festoon bulb

put "festoon bulb", 477 hits
in google/images and first page is nearly full of them

There`s plenty if you Google for Dome Light bulb I bet


I`ve always thought of a festoon lamp as having metal endcaps, we used
them a lot on slot machines back in the 60`s. I`ve never thought of
wire ended miniature tubular lamps as festoons.

There was at one time available a flexible strip containing lots of back
to back clips (like open fuseholders) specifically for making up
"festoons" of lighting - I`m going back to the days of the old
RadioSpares catalogue here. I always imagined that`s where the name
festoon lamp came from.

Ron(UK)
 
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