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Subject: Re: [Homebrew_PCBs] Re: For a DIY exposure box ... is collimated light an issue?

From: brane2 <brankob@...>
Date: 2013-07-07

Of course. I was thinking about twelve inches of lead just for an outer
part of the shield. Im kind of lingering between Uranium and
Kurchatovium for inner part.

On a related note, I never jerk off outside of hazmat suit. Better safe
than sorry.

Chill out a little FFS...













Dne 07. 07. 2013 15:37, pis(e epa_iii:
>
> If you are going to insist on building a device with lamps that are a
> danger to view, then you should definitely consider the idea that this
> device may not always be in your possession or control. It could fall
> into other hands by any number of circumstances. I would highly urge
> that you take precautionS from the design stage and implement them in
> the construction BEFORE the device is operational. I deliberately used
> a capitol "S" to emphasize that more than one precaution should be taken.
>
> As a minimum I would suggest that:
>
> 1. The light be completely contained with zero leakage when it is on.
>
> 2. There should be an automatic kill switch when the device is opened
> and the light is exposed.
>
> 3. There should be a plainly worded warning permanently affixed to the
> exterior of the device. It should state the nature of the danger AND
> what precautions should be taken.
>
> I am not an expert on these particular devices, but I do have a fairly
> good knowledge of optics and have made PCBs using a simple contact
> printing frame and an external light source a couple of feet away. I
> personally think that unless you are presently making boards with very
> fine features AND are having problems with the process that you can
> attribute to uncollimated light, then this whole subject is just a
> waste of time. I doubt that very many home or small scale industrial
> makers of PCBs have anything to worry about here.
>
> Make or buy a simple contact printing frame. Use an external light
> that is about 1.5 to 2.5 feet away. Do not move the light or frame
> while exposing the board. This should work in 99.999% of all cases.
> Then, even if you are having a problem, I would suspect other sources
> of trouble first. Or use the old standby, sun light. That is very
> collimated: probably more so than any device you will construct.
>
> Oh, and do be sure that the emulsion or printed (ink/toner) side of
> your negative/positive is the one in contact with the board.
>
> Paul A.
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Harvey White <madyn@...> wrote:
> >
> > On Sat, 06 Jul 2013 18:57:55 +0000, you wrote:
> >
>
> ...<SNIP>...
>
> >
> > There are reasons why EPROM erasers have a kill switch on the lights
> > when the enclosure is opened. You can seriously damage your sight
> > with these lamps, since they are made to be germicidal.
> >
> > Please read up on them if you haven't, and observe all the safety
> > precautions.
> >
> > Harvey
> >
> >
> >
>
> ...<SNIP>...
>
> > >[Non-text portions of this message have been removed]
> >
>
>



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