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i need more color???

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eternalsoul21

New Member
hi,
too close too a complete prototype.i'm working on this project that has a big problem with the light source.i had to paint the bulbs with some lamp dip first.i'm using an incandescent lamp(9v500mA).and it is way too dim.so i tried a 12v 55 watt halogen bulb.it's brite enough,but my project doesn't work because of the lamp dip.this paint from rosco chips off very easily and burns off over 20watts.i've searched and searched and found nothing over the web for some high heat transparent paint.anyone know of some lamp dip that is good to use for these high intensity bulbs.
thanks,
 

laroche73

New Member
what are you trying to do with the paint? You'd have more luck catching a greased pig than making paint stick to an active halogen lamp. Halogen lamps provide a nice white light, but still produce a lot of energy in the infra-red region, as you've seen.

Is there a reason you can't use a color filter placed a safe distance from the lamp?
 

eternalsoul21

New Member
Reply:thanks for taking the time

{what are you trying to do with the paint? You'd have more luck catching a greased pig than making paint stick to an active halogen lamp. Halogen lamps provide a nice white light, but still produce a lot of energy in the infra-red region, as you've seen.

Is there a reason you can't use a color filter placed a safe distance from the lamp?

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..........................................................................................................i want to paint a small halogen lamp,i can't use a filter because i need light from the whole area of the bulb.i need a bright color for my project so i have to use a brighter bulb and maybe a darker shade of paint so i get a nice color.where can i get paint for a bulb with high intensity.here's a little more info on halogen bulbs.

A halogen bulb uses a chemical trick to prolong the life of its filament. In a regular bulb, the filament slowly thins as tungsten atoms evaporate from the white-hot surface. These lost atoms are carried upward by the inert gases inside the bulb and gradually darken the bulb's upper surface. In a halogen bulb, the gases surrounding the filament are chemically active and don't just deposit the lost atoms at the top of the bulb. Instead, they react with those tungsten atoms to form volatile compounds. These compounds float around inside the bulb until they collide with the filament again. The extreme heat of the filament then breaks the compounds apart and the tungsten atoms stick to the filament.

This tungsten recycling process dramatically slows the filament's decay. Although the filament gradually develops thin spots that eventually cause it to fail, the filament can operate at a higher temperature and still last two or three times as long as the filament of a regular bulb. The hotter filament of a halogen bulb emits relatively more blue light and relatively less infrared light than a regular bulb, giving it a whiter appearance and making it more energy efficient.
 

laroche73

New Member
halogen bulbs

Thanks for the refresher, I worked with halogen bulbs a long time ago, as part of a bar code reader design, but had forgotten about the recycling process that takes place internally. I realize halogen bulbs emit more light towards the blue end of the spectrum, but a significant portion of their output still falls in the IR region. That's why the bulbs burn so hot.

Another point is to be careful handling the bulbs, try not to touch the glass, and wipe off any fingerprints that accidently get on the surface or the bulb life can be shortened significantly.

I guessed the reason you couldn't just use a filter after posting, many applications have a need for the whole bulb area. I'm no expert on high-temp paints, haven't seen anything like that used on halogen lamps. Maybe something can be baked on, any lamp experts out there have some insights?
 

Jalor

New Member
Have you thought about using a domed shaped filter, it will allow full distrubtion of light, but can still keep a good distance from the lamp. if you use a glass 'bowl' it will have a good chance that any colour applied will remain, or you could have it pre coloured. can't tell ya where to get something like this from, but it could be a possibility. there's my 2c (AUD) thrown into the mix.
 

eternalsoul21

New Member
thanks for the info

hey i was woundering is it possible to make my own transparent paint by mixing clear lacour with a color say green lacour paint.lacour hardens good but don't know if it will work on a halogen bulb though
 

laroche73

New Member
high-temp paint

sometimes you need to experiment a bit..

a laquer-based coating will probably burn right off, you could test it on a small area to find out. Another possibility is to try mixing a high-temp epoxy with the color dye of your choosing. I'd also test this out on a small area first.

**broken link removed**

The maximum service temperature for 550 epoxy is listed at 450-500 degrees F, and it should be cured at 250 deg. F for 2 hrs.

Halogen bulbs need to operate at a minimum temperature for the halogen-tungsten cycling to occur, the following link says that temperature is 200 degrees C. [200 * (9/5)] + 32 = 392 degrees F, so you may be within range of the epoxy if you don't run the lamp too hot. - CAL

**broken link removed**
 
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