On 07/08/2013 12:27 AM, Phil@Yahoo wrote:
> Wow.
>
> Interesting story, though it doesn't seem very relevant.
>
> I guess that's the sort of thing we can look forward to
> as a result of emphasizing self-esteem over achievement
> in our public schools. If we manage to dumb down
> everyone to the lowest common denominator then no one
> will ever do anything dangerous because they won't know
> how. And we wouldn't need groups like this one.
>
> Here's something that will make your hair stand on end:
> My exposure box design is the eventual result of a YouTube
> video I saw where a guy used Hg vapor lamps with the
> glass envelop broken off because apparently ∗any∗ such
> bulb will produce the necessary radiation if the borosilicate
> envelope is removed. I was trying to make the thing as cheap
> as possible, so I tried it. Turned out the exposure time was
> longer than I wanted and then I found an Hg bulb made for
> "safe" UV and so used that. $10 for the bulb and $40 for
> the ballast, some MDF and cheap drawer slides and voila!
> A spiffy exposure box with reasonably fast exposure times.
> Does it leak? Sure, some, but not much. I squint when I
> slide the drawer out. The problem with Hg lamps is that
> they require a minute to "warm up" and you can't turn them
> on again right away if you turn them off, so interlock switches
> are not practical. I thought about some elaborate mechanical
> interlocks, but decided not to make "perfect" the enemy of
> "good enough." The advantage of the Hg lamp is it is nearly
> a point UV source. I haven't been able to do 8/8 yet but I
> have done 12mil traces with spaces probably less than 8.
> My biggest problem now is making high-enough quality masks.
> --
> Phil M.
>
HG vapour lights have the same UVC wavelength as the germicidal lamps,
i.e. 273 nm.
Not to poke your eye with a couple of fingers :-) Hg vapour lamps with
broken outer shell produce a lot of Ozone (O3) which in higher
concentrations can kill you by suffocation.
O3 is happily received by haemoglobin in our red blod cells, but the
rest of our bodily cells have no clue how to use that variety of Oxygen.
Oxygen depravation = suffocation = untimely meeting with ... :-)
--
Best Regards,
Q Systems
Zoran A. Šćepanović
zastos@...Skype: zoran.a.scepanovic
http://zastos.com+381 63 609-993
-..-
If a fish is to get away, you must catch it first.