Paddywhacker - 14-3-2009 at 19:35
I was able to improvise a suitable UV source from an EPROM eraser bought on ebay.
A unit from http://www.virtualvillage.au.com/ puts out enough far UV to make the TLC plate fluorophor fluoresce without putting out much visible light to
swamp the viewing. It can easily be disassembled for mounting in a viewing box, but I just drilled a big hole in the casing to let the light out.
chief - 14-3-2009 at 23:53
One could smash the outer bulb from a standard Hg-vapor-bulb ; it has 2 bulbs: The outer one, with some phosphor in it, and the inner one, which burns
happily still without the outer one ...
This inner one gives a strong smell of ozone after a short time: It's real UV ... ; never look into it or into the light reflected from any planes
etc.
kclo4 - 14-3-2009 at 23:56
Why can't a blacklight work?
I know its not really a powerful source of UV, but it has very little visible light coming off.
Sorry I don't know much about this as I've never done this.
indigofuzzy - 15-3-2009 at 00:13
Blacklights are long wave (or near) UV. (aka UV-A). THe peak is around 370nm.
Eprom erasers have a much shorter wavelength.
Eclectic - 15-3-2009 at 01:29
How short a wavelength do you need? There are UV leds now that emmit at 350-360mn
vulture - 15-3-2009 at 02:51
Standard issue TLC plates fluoresce at 254nm, that is the main emission line of Hg vapor. Any fluorescent lighting actually emits this, but for
lighting use it's converted through so called "phosphors" (which is a technically incorrect term) to visible light.
chief - 15-3-2009 at 03:21
Wtih the specialty of the inner-tubing of high-pressure-mercury-bulbs beeing of _quartz_glass_, which lets all the UV out of the bulb ; ordinary glass
would filter it, but with these high-pressure bulbs the phosphor can't be applied directly onto the Hg-containing bulb, probably due to the
temperature.
Therefore: If the outer bulb (with the phosphor) is broken, with the inner one still intact: That will be one of the most raw UV-sources available. As
I said: Strong ozone smell ... ; probably more than one reaction can profit from that too ... ;
not_important - 15-3-2009 at 23:51
Note that some mercury lamps are evacuated/inert gas filled inbetween the inner and out bulb, with a link that will open if the outer bulb cracks,
admitting air. Not all do, and you can jumper around the link if a particular lamp does.
BabyBird - 14-4-2009 at 12:30
just phone up stamp collecting suppliers, battery powered handheld UV 254 lamps are £20. there are two types for examining stamps, the long wave
360nm or so used for seeing fluorescence and the shortwave tubes UV254 used for phosphorescence.
they are cheap perfect for TLC and last a long time.
If you are going to use UV254 tubes get some UV protecting goggles because unlike long wave blacklight it does damage your eyes quickly and it hurts.