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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE! |
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2nd Jul 2017, 4:49 pm | #1 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Coloured glass dials and bulbs
Quite a few vintage hifi receivers and tuners use coloured bulbs to illuminate the dials and meters etc. More often than not - pretty much always - replacement bulbs are plain glass. I use Pebeo Vitrail transparent coloured glass paint to obtain the colour required. It's not that expensive for a smallish bottle at around £4 and you can get a wide variety of colours. I'm sure there are other uses for it in vintage wireless, audio, TV, video, whatever. Click on the colour chart link on this page:
http://en.pebeo.com/Creative-leisure...-Glass/Vitrail One point, remember that an incandescent bulb glows yellow, and this affects the final colour greatly. So for example, applying cobalt blue paint to the bulb glass gives rise to a cyan (greeny blue) 'output' colour.
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A digital radio is the latest thing, but a vintage wireless is forever.. |
2nd Jul 2017, 6:23 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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Re: Coloured glass dials and bulbs
In times-past I've "coloured over" the bulbs with a green or red OHP transparency-marker pen to get the required rendition.
[These days, most people wouldn't understand overhead-projector foils or their associated spirit-marker pens] |
2nd Jul 2017, 8:29 pm | #3 |
Guest
Posts: n/a
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Re: Coloured glass dials and bulbs
Such as these https://www.amazon.co.uk/Schneider-2...ds=ohp+pen+set
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2nd Jul 2017, 8:57 pm | #4 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Re: Coloured glass dials and bulbs
Until I discovered this paint, I also tried colour pens without much success. I found that they just didn't have the thickness or depth of colour to influence the final result enough. At least, that's what I've found with hifi receivers. But then again the bulbs in hifi receivers are often quite bright. Maybe the pens I tried did not give off enough ink to get a good, thorough covering of colour filter. But if it worked for you guys then it must be possible for sure.
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A digital radio is the latest thing, but a vintage wireless is forever.. |
2nd Jul 2017, 11:16 pm | #5 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,345
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Re: Coloured glass dials and bulbs
I use transparent paint that you can find in shops that sell plastic models for renovating faded Christmas tree lights.
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6th Jul 2017, 1:51 pm | #6 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Re: Coloured glass dials and bulbs
Here's a measure of how intense the filter has to be in order to affect or 'colour' the light emitted from the bulb. Until my glass paint arrives (it's just arrived actually) I tried using the blue plastic film that is used to insulate old style electrolytic capacitors. I used two wraps of the film on the 'fuse' style bulb. Attached are the results with and without flash. The effect on the dial scale is zero; no change to the colour. In the first two photos, left to right you can see the original bulb with its factory applied blue filter, a couple of blue electrolytic caps (one minus it wrapping that I used) and the receiver. You can see that the meters (above) are the proper blue/green colour, but the tuning dial is still, for all intents and purposes, white. The third photo shows an original bulb on the left, with a new bulb plus the 'blue capacitor' filter on the right. Looking at them, there doesn't seem to be much difference between them, but in use one works as a blue filter, the other not. Looks are deceiving and never so much so as in the case of coloured light filters!
Later today I will apply the blue glass paint to the new bulbs and - having used this stuff before - the difference should be obvious. So, next post coming soon (when a couple of coats of paint have dried..).
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A digital radio is the latest thing, but a vintage wireless is forever.. |
6th Jul 2017, 3:21 pm | #7 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,345
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Re: Coloured glass dials and bulbs
It's probably to do with the fact that traditional tungsten filament incandescent bulbs predominantly radiate energy at the red end of the spectrum. The "Daylight" GLS bulbs that you can (could?) buy in shops that sell artists' supplies have quite a heavy layer of blue lacquer in order to make the light they emit a good approximation to noon sunlight. The human eye is most sensitive to the yellow/green part of the spectrum, so a really heavy layer of blue filter is necessary to make filtered light look blue. I recall that the filter that you used to need for taking colour photos in artificial light using colour slide film balanced for daylight, greatly reduced its effective film speed.
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9th Jul 2017, 4:48 pm | #8 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Re: Coloured glass dials and bulbs
I used my new Cobalt Blue glass paint and the result was too blue - see 1st photo. So then I tried my existing bottle of Emerald Green, and it was.. too green. So I made a mix of 2/3 green and 1/3 blue - perfect, see photos.
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A digital radio is the latest thing, but a vintage wireless is forever.. |
10th Jul 2017, 3:01 am | #9 |
Heptode
Join Date: Oct 2005
Location: Olympia, Washington, USA.
Posts: 664
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Re: Coloured glass dials and bulbs
General Cement Co. aka GC made a dial light coloring kit back in the late 60's. I still have one, but have not used it in decades. IIRC, it was some sort of lacquer semi transparent paint. Od course, in an emergency, finger nail polish seemed to work OK too.
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