1   Lamps / Vintage & Antique / Re: Lighting up the Philips 400w MV lamp - dimly?  on: Today at 11:44:43 AM 
Started by Laurens - Last post by RRK
Cutting the lamp neck evenly is a bit tricky. Classic glassblowers tricks are to do a deep circular scratch in the loop across the neck with a diamond or carbide wheel cutter, wet it with saliva or just water and then to apply a local thermal stress - touch with a melted tip of a thin glass stick or tube. Propagate the crack with repeated touches. Or use a loop of nichrome wire of about 0.5mm diameter. Wrap the wire across the glass and heat to dull red for about 10 seconds, then remove and briefly touch the glass with a wet finger. It should crack cleanly because of thermal stress. Or use both circular scratch and nichrome at the same time. The success depends on the type of the glass used. Soft glass with high coefficient of expansion is the easier to cut that way. Hard glasses like boro or alumosilicate may be reluctant to thermal shock because of inherently low COE and may be easier just to carefully cut with a fast rotating thin jeweler's diamond disk with a bit of water to cool.

It may be a good idea to relieve the vacuum inside the lamp, because a fast inrush of air as you cut it may blow off some phosphor. Some ideas may be to start the partial crack but then let the lamp alone for about a hour to leak, and then finish, or get access to the pumping tubulation inside the base/stem, for example with gentle cracking the black vitrite insulator. Melted tubulation tip usually holds a high residual stress, and if heated quickly with a sharp butane torch, will crack and slowly let the air in. Or you may try just to break the tubulation, though there is again some risk of blowing off the phosphor. 

Wrap the lamp body with a thick towel to avoid cuts on mishap. Note that if the area to cut is poorly annealed and holds some stress, it will never cut cleanly whatever care is used. May be only if the whole lamp is re-annealed in the oven. So do not blame yourself if the cut will not work out. Practice on some junk lamps.

Regarding phosphors. First, in a HPM lamp mercury and the discharge do not contact the phosphor until something very bad happens, so it ages to much less extent then in fluorescent lamps for comparison. So it should not be completely dead even in well aged lamps. There are many types of phosphors in HPM lamps, some are reactive to UVA and some not. Modern DX europium-activated vanadate almost does not react. Older Mn activated fluorogermanate strongly light-ups with that pretty ruby color at about 650nm. Not sure about other types, cheap orange silicate will be probably dead in UVA too. Interestingly, as your lamp is the old Philips, it may use a rare red Mn activated arsenate phosphor instead of fluorogermanate in fact!
 2   General / Off-Topic / Re: How do I fit in?  on: Today at 10:50:15 AM 
Started by Silverliner - Last post by rjluna2
Even there is no discussion on these picture that you have posted, sometimes I do feel little disappointed.  If any rate that will make you feel better, go to your gallery and see how many times they have viewed at your recent post.  That's what I usually do :)
 3   General / Off-Topic / How do I fit in?  on: Today at 09:21:05 AM 
Started by Silverliner - Last post by Silverliner
Hello everyone,

How do I fit in? Upload anything worth discussing? Do I just have a very low self esteem? If I had a high self esteem would I have forgotten I uploaded pics and not notice if they get comments or not? I really have no clue honestly how some seem to fit in and others cannot.
 4   Lamps / Vintage & Antique / Re: Lighting up the Philips 400w MV lamp - dimly?  on: Today at 07:03:40 AM 
Started by Laurens - Last post by Laurens

A fun idea may be to stuck some small germicidal lamp into a HPM envelope ;)
I could do that with one of the completely worn out HPL-N 80w's i'm getting sooner or later, but not with this huge thing. There's a decent risk of the outer bulb shattering, and i wanna keep it in working order.

I've chucked a bunch of 365nm LEDs in my Aliexpress basket. I'll see how well i can make that work.

Actually, the lamp you have here is probably fluorogermanate coated as it reacts strongly to UVA. You can mount a strong small UVA source (a small blacklight tube or high power UVA LED module) just behind it to make this pretty deep red ruby glow permanent, without any wearing of the collectible lamp.
Which phosphors respond to which wavelenghts? I've noticed my modern HPL-Ns barely (if at all) respond to 365nm. That said, it may very well be that the phosphors of those lamps have gotten very worn out by now.
 5   Lamps / Vintage & Antique / Re: Bulbs with black arc tubes  on: Today at 05:22:13 AM 
Started by Cole D. - Last post by Philips tigkas
Have you tried from an other device?
 6   Lamps / Vintage & Antique / Re: Bulbs with black arc tubes  on: Today at 05:20:37 AM 
Started by Cole D. - Last post by AngryHorse
I’ve got two interesting examples, but for some reason my phone, or the gallery won’t let me attach them??? :wndr:
 7   General / Dating & Specifications / Re: Which lamp is older?  on: Today at 04:44:12 AM 
Started by RadiantMV - Last post by LightbulbManiac
The only date code I could decode is for the second lamp since on the first one I can't clearly see the date code.
57 = May 1967/1977
 8   Lamps / Vintage & Antique / Re: Lighting up the Philips 400w MV lamp - dimly?  on: Today at 01:14:16 AM 
Started by Laurens - Last post by RRK
Actually, the lamp you have here is probably fluorogermanate coated as it reacts strongly to UVA. You can mount a strong small UVA source (a small blacklight tube or high power UVA LED module) just behind it to make this pretty deep red ruby glow permanent, without any wearing of the collectible lamp.
 9   Lamps / Vintage & Antique / Re: Lighting up the Philips 400w MV lamp - dimly?  on: Today at 01:04:18 AM 
Started by Laurens - Last post by RRK
Running a HPM lamp with a glow discharge will inevitably kill the electrodes rather quickly, just because of sputtering.

Some other choices to have that pretty pink glow is to get a red CFL or CCFL tube, pink sort of T8 fluorescent (these are made fluorogermanate, more dirty reddish color, or red europium phosphor - you want that one) or have a neon maker made you a tube with a 'coral pink' phosphor.

A fun idea may be to stuck some small germicidal lamp into a HPM envelope ;)

 
 10   General / Off-Topic / Re: Any Sport Car Owners?  on: February 20, 2024, 11:35:01 PM 
Started by suzukir122 - Last post by Highway125
Technically more of a Muscle car, but it is still very sporty... 

I have a Candy Apple Red 1966 Ford Mustang Notchback Coupe my family inherited from my grandfather.

It originally ran on tracks for time attack and short course class racing prior to my grandfather buying it off of his friend who ran it in said racing classes. so its pretty peppy and tricked out!
Has a smallblock 302 bored and stroked out to 331ci with alloy heads and billet internals,
QuickFuel double-pumper carb, Tremec T5 transmisson and a Hurst hydraulic racing clutch.

boy is it fast!! Such a fun little car!  8)
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