Hey all,

For the longest time I've always wanted a fluorescent lamp with no phosphor coating, so I could see the arc inside and electrodes in action.  Yes, I know there are germicidal lamps, but they exist solely to pump out quite harmful amounts of UV, so I'm not gonna mess with those.  And I've heard of demo lamps being made for salespeople by lamp companies, with one half of the tube unphosphored, to show the internal construction of lamps.  But those must be rare beasts indeed!

Has anyone thought about creating custom fluorescent lights here?  What would your wish list include?
Here's mine:

• regular T8 or T12 fluorescent lamp in all respects except for no phosphor coating.  In essence a low-pressure hot-cathode mercury arc lamp but with no dangerous UV like in germicidal lamps.
• no phosphor again, but this time with Penning mixture of argon-neon to colour it up!  Pure neon would probably kill the cathodes in no time, unfortunately, and be difficult to start.  This would be in T12 VHO, which would bring me as close as I'm ever likely to get to an NE-H ;-)

I do know it is possible to have custom fluorescent lamps made, for instance you can go to LCD Lighting, Inc. - Custom Fluorescent Lamps but I am scared to even think about how expensive it would be to order a one-off or very small batch of custom lamps!

There have been some members here that have found bulbs that "rattle" because one of the little shields fell off the electrode.
Then using a permanent magnet the shield is used as a scraper to scrape off the coating inside the bulb and then you have a clear bulb.

I have a F90T17CW that the shields fell off of and still works great, but because the F90T17s are so rare now I don't want to ruin it scraping off the coating.

I have found "rattle" bulbs in the past, but never thought of scraping off the coating with a magnet .
Some times stores will give you these bulbs for free if you point out that they rattle and are a manufacturing defect.

   

Half coated lamps can be ordered from Boreal Northwest laboratory but they are expensive at 81 $ each !  The same company sells standard Gro-lux lamps for 31 $ each, though. School laboratory suppliers always have relatively high prices. I am not sure if they sell to the public or not, though, as I never ordered from them except through the school account.

Well I spose $81 is better than what I was thinking it would cost to order custom-made ones!
Thanks for the link sol!

Larry: yes I've seen posts here where folks deliberately scrape off the phosphor, but apparently all that loose phosphor inside wreaks havoc on the electrodes, and it just doesn't look as nice as a truly clear lamp.  Still, something to try if I come across a broken lamp (I'm too cheap to 'break' a good working lamp myself) ;-)