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Re: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage - 400W floodlight instead?

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  • Robin Whittle
    Hi John, Generally, gas discharge tubes cannot be operated in parallel. They need a high voltage to start, but settle down to a low voltage ca. 90 volts (I
    Message 1 of 17 , Aug 1, 2012
      Hi John,

      Generally, gas discharge tubes cannot be operated in parallel. They
      need a high voltage to start, but settle down to a low voltage ca. 90
      volts (I guess) once they are conducting. With ordinary inductor
      ballasts I have seen two 20W short tubes, each with their own starter,
      wired in series with a 40W ballast. This is for 240V. Maybe that would
      work with a high frequency electronic ballast.

      I chose to use a 500 watt floodlamp from the hardware store. The short
      linear quartz halogen lamps give off a lot of near UV, which is what I
      want for exposing Riston negative photoresist.

      At a distance of about 45cm I have exposure times of 2 to 3 minutes.

      This is a much narrower angle source of light than having a bunch of
      fluorescent tubes only 10cm away, so for a given phototool and possible
      distance from the phototool to the top and bottom of the Riston, I get a
      much sharper image (shadow).

      The only potential concern I can think of is heating of the phototool,
      PCB and whatever means is used to hold them together. I have a fan
      blowing on them to keep them cool.

      There's no warm-up time for a QI light. Tubular fluorescent lamps are
      likely to have some kind of warm-up time, making it difficult to predict
      their light output unless they have just been running and are fully
      warmed up. High pressure mercury vapor lamps have much longer warm-up
      times, and so do the compact fluorescent lamps which are now widely
      used. All these fluorescent lamps - tubular, 400W (or other wattage)
      high pressure mercury vapor lamps, and compact fluorescent lamps - come
      in "black light" versions which I think put out the ideal wavelength for
      exposing Riston.


      http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.html

      I haven't looked at all the types, but the types I have looked at are
      specified to respond best to 350 to 380nm light. This datasheet for a
      400W high pressure mercury vapour fluorescent H500-BL:

      http://www.eyelighting.com/tb/Mercury/MVR/EQS-N-52-78-69917.pdf

      shows most of the output at about 370nm.

      However, I think their warm-up times are a problem.

      QI lamps will vary their near UV output somewhat according to their
      operating voltage, but unless the mains voltage varies widely, I would
      be surprised if this variation was enough to cause trouble with Riston.


      - Robin http://www.firstpr.com.au/pcb-diy/
    • Paul
      Hi John I don t know about the ballast question, in my old commercial but un-branded box which I got from a rally it matches the tubes. Mine has 2 x 8W 29cm
      Message 2 of 17 , Aug 1, 2012
        Hi John

        I don't know about the ballast question, in my old commercial but
        un-branded box which I got from a rally it matches the tubes.

        Mine has 2 x 8W 29cm tubes which are fine for exposing the size of
        boards I make. The clear glass area is 15 x 25cm and the tubes are
        spaced 9cm apart. There's a flat foil reflector behind the tubes.
        Exposure time with Mega pre-sensitised board is about 3 minutes.

        Curious what you are going to do for a timer? Mine doesn't have one and
        fitting one is on the list of things to do in the shack.

        Regards

        Paul G4DCV

        On 01/08/2012 07:50, v321uk wrote:
        >
        > When buying an HF ballast and fluorescent tube does the ballast
        > wattage have to match the tube wattage?
        >
        > Is it allowable to use an hf ballast of higher wattage that that of
        > the tube e.g. hf ballast 40W tube 12W ?
        >
        > Can you parallel tubes to an hf ballast intended for a single tube so
        > long as ballast wattage is sufficient ?
        >
        > I am building a uv-a light box for sensitised PCB exposure and am not
        > sure how many tubes to use.
        > I am thinking get a higher wattage than needed hf ballast and say two
        > 8 or 12W tubes so if there is insufficient light I could get one or
        > two more tubes and parallel them.
        >
        > I usually use the sun for exposure but there has not been much of it
        > here over the last few weeks and I need to make a PCB.
        >
        > Thanks
        > John G3UGY
        >
        >
        >
        > No virus found in this message.
        > Checked by AVG - www.avg.com <http://www.avg.com>
        > Version: 2012.0.2197 / Virus Database: 2437/5167 - Release Date: 07/31/12
        >



        [Non-text portions of this message have been removed]
      • Russell Shaw
        ... I got a 380nm 10W LED. I haven t tried it yet.
        Message 3 of 17 , Aug 1, 2012
          On 01/08/12 17:18, Robin Whittle wrote:
          > Hi John,
          >
          > Generally, gas discharge tubes cannot be operated in parallel...

          I got a 380nm 10W LED. I haven't tried it yet.

          <http://www.ebay.com.au/itm/10W-Ultra-Violet-UV-High-Power-Led-Light-380nm-385nm-/230760896509?pt=LH_DefaultDomain_0&hash=item35ba6bd7fd>

          You can get a 100W one for "only" $999.99 ;)

          <http://www.ebay.com.au/itm/380nm-385nm-Ultra-Violet-UV-High-Power-LED-Light-100W-/360445882648?pt=LH_DefaultDomain_0&hash=item53ec3fb118>


          I was going to try it for curing UV glue and ink, but it would probably do good
          for photoresist too.

          An array of 1W LEDs could be an option too.


          Do not stare at these when illuminated. It could cause photopolymerisation
          (cloudiness) in the eye.
        • John Anhalt
          Regarding parallel vs. series, wouldn t putting the bulbs in series decrease the starting voltage available for each? In series, they share the same current,
          Message 4 of 17 , Aug 1, 2012
            Regarding parallel vs. series, wouldn't putting the bulbs in series decrease the starting voltage available for each? In series, they share the same current, and in parallel, the voltage drop across each is the same. So much for theory.

            Actually, it is a bit more complex than that. Here is a rather lengthy discussion by Philips:http://www.advance.philips.com/documents/uploads/literature/1-01%20to%201-69_Atlas2012.pdf

            Page I-7 discusses parallel vs. series. Page I-35 begins a section on wiring. Note that for high-frequency devices, there are other considerations. The best answer might be to look up your specific ballast to see how it should be wired for multiple bulbs.

            Parallel vs. series may be complicated by the nomenclature used. If the bulbs share a common (e.g., white wire), then I would say they can't be in series.

            John



            ----- Original Message -----
            From: Robin Whittle
            To: Homebrew_PCBs@yahoogroups.com
            Cc: v321uk
            Sent: Wednesday, August 01, 2012 3:18 AM
            Subject: Re: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage - 400W floodlight instead?



            Hi John,

            Generally, gas discharge tubes cannot be operated in parallel. They
            need a high voltage to start, but settle down to a low voltage ca. 90
            volts (I guess) once they are conducting. With ordinary inductor
            ballasts I have seen two 20W short tubes, each with their own starter,
            wired in series with a 40W ballast. This is for 240V. Maybe that would
            work with a high frequency electronic ballast.

            I chose to use a 500 watt floodlamp from the hardware store. The short
            linear quartz halogen lamps give off a lot of near UV, which is what I
            want for exposing Riston negative photoresist.

            At a distance of about 45cm I have exposure times of 2 to 3 minutes.

            This is a much narrower angle source of light than having a bunch of
            fluorescent tubes only 10cm away, so for a given phototool and possible
            distance from the phototool to the top and bottom of the Riston, I get a
            much sharper image (shadow).

            The only potential concern I can think of is heating of the phototool,
            PCB and whatever means is used to hold them together. I have a fan
            blowing on them to keep them cool.

            There's no warm-up time for a QI light. Tubular fluorescent lamps are
            likely to have some kind of warm-up time, making it difficult to predict
            their light output unless they have just been running and are fully
            warmed up. High pressure mercury vapor lamps have much longer warm-up
            times, and so do the compact fluorescent lamps which are now widely
            used. All these fluorescent lamps - tubular, 400W (or other wattage)
            high pressure mercury vapor lamps, and compact fluorescent lamps - come
            in "black light" versions which I think put out the ideal wavelength for
            exposing Riston.

            http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.html

            I haven't looked at all the types, but the types I have looked at are
            specified to respond best to 350 to 380nm light. This datasheet for a
            400W high pressure mercury vapour fluorescent H500-BL:

            http://www.eyelighting.com/tb/Mercury/MVR/EQS-N-52-78-69917.pdf

            shows most of the output at about 370nm.

            However, I think their warm-up times are a problem.

            QI lamps will vary their near UV output somewhat according to their
            operating voltage, but unless the mains voltage varies widely, I would
            be surprised if this variation was enough to cause trouble with Riston.

            - Robin http://www.firstpr.com.au/pcb-diy/





            [Non-text portions of this message have been removed]
          • Robin Whittle
            Hi Russell, In Re: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage - 400W ... Wow!!! ... I think the 10 watt (power consumption) one would do the
            Message 5 of 17 , Aug 1, 2012
              Hi Russell,

              In "Re: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage - 400W
              floodlight instead?" you wrote:

              > I got a 380nm 10W LED. I haven't tried it yet.
              >
              > http://www.ebay.com.au/itm/10W-Ultra-Violet-UV-High-Power-Led-Light-380nm-385nm-/230760896509

              Wow!!!

              > You can get a 100W one for "only" $999.99 ;)
              >
              > http://www.ebay.com.au/itm/380nm-385nm-Ultra-Violet-UV-High-Power-LED-Light-100W-/360445882648

              I think the 10 watt (power consumption) one would do the trick. In
              PCB-DIY I don't think we are in a tearing hurry for exposure time.

              I think you would need to attach it to a fancy heatsink, with
              appropriate heat conductive paste, to keep it cool and happy.

              This would make a very small angle source of UV for exposing Riston and
              the like. This would make it less critical to get the phototool in
              close contact with the Riston.

              I don't know what the UV output of the 400W floodlight is. However it
              should be possible to guess an exposure time at a similar distance - in
              my case 45cm for this LED. Let's say this LED put out 70% of its light
              on an area 50cm x 50cm. Assuming it puts out 1 watt (as the eBay
              listing suggests, for ~1000mA at ~10 volts) then this is 7 watts on 0.25
              square metres, or 28 watts per square metre = 2.8 x 10^1 watts per
              square metre. This is 2.8 x 10^-3 watts (2.8 milliwatts) per square cm.

              Looking at a Riston datasheet, for MM540:

              http://www2.dupont.com/Imaging_Materials/en_US/assets/downloads/datasheets/mm500series.pdf

              the exposure energy for 350 to 380nm is (table on bottom right of page
              2) 25 to 55 millijoules per square cm.

              So according to theory, this LED should expose the Riston in 10 to 20
              seconds!

              For larger boards, to get an even exposure, it would make sense to move
              the LED to a greater distance, with exposure time quadrupling for each
              doubling of distance.

              A significant advantage of this LED compared to the 400W floodlight is
              no significant heating of the PCB and phototool, and therefore no need
              for a fan.

              > I was going to try it for curing UV glue and ink, but it would
              > probably do good for photoresist too.

              I think it would be excellent for all these purposes.

              > An array of 1W LEDs could be an option too.

              Yes.

              > Do not stare at these when illuminated. It could cause
              > photopolymerisation (cloudiness) in the eye.

              Unlike a quartz halogen floodlight, which is seriously bright, the UV
              LED may not seem vary bright to the eye. I guess it would activate our
              retina to some extent, since it is so bright and since its spectrum
              presumably has some width extending into our violet range:

              http://en.wikipedia.org/wiki/Cone_cell

              I think eye protection would be essential for a device like this. I
              wear sunglasses when operating the 400W floodlight. Maybe that would be
              sufficient, since this is near-UV, not the same as shorter-wavelength
              mutation-producing UVB which causes sunburn and cancer.

              - Robin http://www.firstpr.com.au/pcb-diy/
            • v321uk
              Hi Paul, Thanks for the info on the commercial unit. Re timer as I need to make a board asap I ll just do it with clock and switch initially. Thanks, John
              Message 6 of 17 , Aug 1, 2012
                Hi Paul,

                Thanks for the info on the commercial unit.
                Re timer as I need to make a board asap I'll just do it with clock and switch initially.

                Thanks, John G3UGY



                --- In Homebrew_PCBs@yahoogroups.com, Paul <paul@...> wrote:
                >
                > Hi John
                >
                > I don't know about the ballast question, in my old commercial but
                > un-branded box which I got from a rally it matches the tubes.
                >
                > Mine has 2 x 8W 29cm tubes which are fine for exposing the size of
                > boards I make. The clear glass area is 15 x 25cm and the tubes are
                > spaced 9cm apart. There's a flat foil reflector behind the tubes.
                > Exposure time with Mega pre-sensitised board is about 3 minutes.
                >
                > Curious what you are going to do for a timer? Mine doesn't have one and
                > fitting one is on the list of things to do in the shack.
                >
                > Regards
                >
                > Paul G4DCV
              • v321uk
                Hi Robin, Thanks for the comprehensive info. Do you think a car quartz halogen headlamp would have sufficient UV output ? I have a new 12V dual filament 50W +
                Message 7 of 17 , Aug 1, 2012
                  Hi Robin,

                  Thanks for the comprehensive info.

                  Do you think a car quartz halogen headlamp would have sufficient UV output ?
                  I have a new 12V dual filament 50W + 65W which I could parallel to give 115W

                  Alternatively, I have a new 12W T5 circular (11cm 41/2") Fly Zapper tube.

                  My PC is only 8cm x 3cm.

                  The sensitised PCB needs energy around 360nm.

                  Thanks,
                  John



                  --- In Homebrew_PCBs@yahoogroups.com, Robin Whittle <rw@...> wrote:
                  >
                  > Hi John,
                  >
                  > Generally, gas discharge tubes cannot be operated in parallel. They
                  > need a high voltage to start, but settle down to a low voltage ca. 90
                  > volts (I guess) once they are conducting. With ordinary inductor
                  > ballasts I have seen two 20W short tubes, each with their own starter,
                  > wired in series with a 40W ballast. This is for 240V. Maybe that would
                  > work with a high frequency electronic ballast.
                  >
                  > I chose to use a 500 watt floodlamp from the hardware store. The short
                  > linear quartz halogen lamps give off a lot of near UV, which is what I
                  > want for exposing Riston negative photoresist.
                  >
                  > At a distance of about 45cm I have exposure times of 2 to 3 minutes.
                  >
                  > This is a much narrower angle source of light than having a bunch of
                  > fluorescent tubes only 10cm away, so for a given phototool and possible
                  > distance from the phototool to the top and bottom of the Riston, I get a
                  > much sharper image (shadow).
                  >
                  > The only potential concern I can think of is heating of the phototool,
                  > PCB and whatever means is used to hold them together. I have a fan
                  > blowing on them to keep them cool.
                  >
                  > There's no warm-up time for a QI light. Tubular fluorescent lamps are
                  > likely to have some kind of warm-up time, making it difficult to predict
                  > their light output unless they have just been running and are fully
                  > warmed up. High pressure mercury vapor lamps have much longer warm-up
                  > times, and so do the compact fluorescent lamps which are now widely
                  > used. All these fluorescent lamps - tubular, 400W (or other wattage)
                  > high pressure mercury vapor lamps, and compact fluorescent lamps - come
                  > in "black light" versions which I think put out the ideal wavelength for
                  > exposing Riston.
                  >
                  >
                  > http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.html
                  >
                  > I haven't looked at all the types, but the types I have looked at are
                  > specified to respond best to 350 to 380nm light. This datasheet for a
                  > 400W high pressure mercury vapour fluorescent H500-BL:
                  >
                  > http://www.eyelighting.com/tb/Mercury/MVR/EQS-N-52-78-69917.pdf
                  >
                  > shows most of the output at about 370nm.
                  >
                  > However, I think their warm-up times are a problem.
                  >
                  > QI lamps will vary their near UV output somewhat according to their
                  > operating voltage, but unless the mains voltage varies widely, I would
                  > be surprised if this variation was enough to cause trouble with Riston.
                  >
                  >
                  > - Robin http://www.firstpr.com.au/pcb-diy/
                  >
                • Robin Whittle
                  Hi John, I am responding to your message in: Re: PCB light box - hf ballast / ... I guess a quartz iodide (AKA quartz halogen) headlight lamp would work OK
                  Message 8 of 17 , Aug 1, 2012
                    Hi John,

                    I am responding to your message in: "Re: PCB light box - hf ballast /
                    tube wattage - 400W floodlight instead?", in which you wrote:

                    > Do you think a car quartz halogen headlamp would have sufficient UV
                    > output ? I have a new 12V dual filament 50W + 65W which I could
                    > parallel to give 115W.

                    > My PC is only 8cm x 3cm.

                    I guess a quartz iodide (AKA quartz halogen) headlight lamp would work
                    OK with a distance suitable for small boards and with a few minutes for
                    exposure. However it would depend greatly on the voltage you ran it
                    from. The UV output of an incandescent filament goes up dramatically
                    with its temperature, so if you ran it from 11 volts and got little
                    action, and from 13 volts and got a much greater UV output, I wouldn't
                    be surprised.

                    With these currents and voltages I think it would be good to use thick
                    wires and measure the voltage at the lamp terminals. I suggest running
                    it at 13.8 volts - which is a typical maximum voltage in a car.

                    Some kind of reflector, such as made from a nicely bent fragment of
                    aluminium pie dish would help.

                    As with the 400W quartz halogen floodlamp, I think heating of the board
                    might be a problem. A fan blowing on the board should fix this.


                    > Alternatively, I have a new 12W T5 circular (11cm 41/2") Fly Zapper
                    > tube.
                    >
                    > The sensitised PCB needs energy around 360nm.

                    I don't know what their output wavelengths are, but as far as I know
                    they are not in the 350 to 380nm near UV range. Do you have a tube
                    number? Googling it should turn up a spec sheet.


                    - Robin http://www.firstpr.com.au/pcb-diy/
                  • John
                    The quartz halogen car headlamp bulb successfully exposed the PCB. I ran the bulb at 13.8V with just the 65W filament connected at a distance of about 4 from
                    Message 9 of 17 , Aug 1, 2012
                      The quartz halogen car headlamp bulb successfully exposed the PCB.
                      I ran the bulb at 13.8V with just the 65W filament connected at a distance of about 4" from the PCB for three and a half minutes.

                      The artwork was produced with SprintLayout v5 and inkjet printed with a canon MP600 on to regular A4 copy paper with printer set
                      to highest quality. I took the inkjet print to a copy centre who photocopied it at darkest setting on to what looked like
                      tracing paper but was probably a plastic material they use to print technical drawings.

                      I will probably get a number lower wattage quartz halogen car bulbs and make up a light exposure box. Quartz halogen car bulbs
                      are easily obtainable and not too expensive and no ballast is needed.

                      I did the test on an old piece of SRBP. I'll repeat it with some new RS glass epoxy FR-4.

                      John G3UGY


                      --------------------------------------------------
                      From: "Robin Whittle" <rw@...>
                      Sent: Wednesday, August 01, 2012 3:01 PM
                      To: <Homebrew_PCBs@yahoogroups.com>
                      Cc: "v321uk" <v321uk@...>
                      Subject: 12 volt QI headlight lamp as UV source for exposing photoresist?

                      > Hi John,
                      >
                      > I am responding to your message in: "Re: PCB light box - hf ballast /
                      > tube wattage - 400W floodlight instead?", in which you wrote:
                      >
                      >> Do you think a car quartz halogen headlamp would have sufficient UV
                      >> output ? I have a new 12V dual filament 50W + 65W which I could
                      >> parallel to give 115W.
                      >
                      >> My PC is only 8cm x 3cm.
                      >
                      > I guess a quartz iodide (AKA quartz halogen) headlight lamp would work
                      > OK with a distance suitable for small boards and with a few minutes for
                      > exposure. However it would depend greatly on the voltage you ran it
                      > from. The UV output of an incandescent filament goes up dramatically
                      > with its temperature, so if you ran it from 11 volts and got little
                      > action, and from 13 volts and got a much greater UV output, I wouldn't
                      > be surprised.
                      >
                      > With these currents and voltages I think it would be good to use thick
                      > wires and measure the voltage at the lamp terminals. I suggest running
                      > it at 13.8 volts - which is a typical maximum voltage in a car.
                      >
                      > Some kind of reflector, such as made from a nicely bent fragment of
                      > aluminium pie dish would help.
                      >
                      > As with the 400W quartz halogen floodlamp, I think heating of the board
                      > might be a problem. A fan blowing on the board should fix this.
                      >
                      >
                      >> Alternatively, I have a new 12W T5 circular (11cm 41/2") Fly Zapper
                      >> tube.
                      >>
                      >> The sensitised PCB needs energy around 360nm.
                      >
                      > I don't know what their output wavelengths are, but as far as I know
                      > they are not in the 350 to 380nm near UV range. Do you have a tube
                      > number? Googling it should turn up a spec sheet.
                      >
                      >
                      > - Robin http://www.firstpr.com.au/pcb-diy/
                      >
                    • v321uk
                      Robin, Fly Zapper tubes are around 350nm but will be changing soon to 368nm The following from:
                      Message 10 of 17 , Aug 1, 2012
                        Robin,

                        Fly Zapper tubes are around 350nm but will be changing soon to 368nm

                        The following from:
                        http://www.lamps-on-line.com/uv-lightbulbs/blacklight-bl350.html

                        Application:
                        The most popular application for BL350 bulbs is in Bug Zappers or Fly Killers.

                        They can also be used for Nail Curing, photopolymerisation and curing of plastics and varnishes.

                        Technical:
                        bulbs emit UV Radiation at 350nm.

                        Recent changes to legislation (RoHS compliance) has meant that
                        lamps in the near future will emit UV radiation at 368nm.

                        Although called Black Light BL350 bulbs are white in appearance and have the same electrical characteristics as standard fluorescent tubes.

                        John G3UGY


                        --- In Homebrew_PCBs@yahoogroups.com, Robin Whittle <rw@...> wrote:

                        > > The sensitised PCB needs energy around 360nm.
                        >
                        > I don't know what their output wavelengths are, but as far as I know
                        > they are not in the 350 to 380nm near UV range. Do you have a tube
                        > number? Googling it should turn up a spec sheet.
                        >
                        > - Robin http://www.firstpr.com.au/pcb-diy/
                      • v321uk
                        Robin, Does your 500W halogen connect directly to the mains or does it need a ballast or current limiter? Do you use a base (socket) how do you connect to the
                        Message 11 of 17 , Aug 1, 2012
                          Robin,

                          Does your 500W halogen connect directly to the mains or does it need a ballast or current limiter?

                          Do you use a base (socket) how do you connect to the bulb?

                          Thanks,
                          John G3UGY





                          > --- In Homebrew_PCBs@yahoogroups.com, Robin Whittle <rw@> wrote:
                          > >
                          > > Hi John,
                          > >
                          > > Generally, gas discharge tubes cannot be operated in parallel. They
                          > > need a high voltage to start, but settle down to a low voltage ca. 90
                          > > volts (I guess) once they are conducting. With ordinary inductor
                          > > ballasts I have seen two 20W short tubes, each with their own starter,
                          > > wired in series with a 40W ballast. This is for 240V. Maybe that would
                          > > work with a high frequency electronic ballast.
                          > >
                          > > I chose to use a 500 watt floodlamp from the hardware store. The short
                          > > linear quartz halogen lamps give off a lot of near UV, which is what I
                          > > want for exposing Riston negative photoresist.
                          > >
                          > > At a distance of about 45cm I have exposure times of 2 to 3 minutes.
                          > >
                          > > This is a much narrower angle source of light than having a bunch of
                          > > fluorescent tubes only 10cm away, so for a given phototool and possible
                          > > distance from the phototool to the top and bottom of the Riston, I get a
                          > > much sharper image (shadow).
                          > >
                          > > The only potential concern I can think of is heating of the phototool,
                          > > PCB and whatever means is used to hold them together. I have a fan
                          > > blowing on them to keep them cool.
                          > >
                          > > There's no warm-up time for a QI light. Tubular fluorescent lamps are
                          > > likely to have some kind of warm-up time, making it difficult to predict
                          > > their light output unless they have just been running and are fully
                          > > warmed up. High pressure mercury vapor lamps have much longer warm-up
                          > > times, and so do the compact fluorescent lamps which are now widely
                          > > used. All these fluorescent lamps - tubular, 400W (or other wattage)
                          > > high pressure mercury vapor lamps, and compact fluorescent lamps - come
                          > > in "black light" versions which I think put out the ideal wavelength for
                          > > exposing Riston.
                          > >
                          > >
                          > > http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.html
                          > >
                          > > I haven't looked at all the types, but the types I have looked at are
                          > > specified to respond best to 350 to 380nm light. This datasheet for a
                          > > 400W high pressure mercury vapour fluorescent H500-BL:
                          > >
                          > > http://www.eyelighting.com/tb/Mercury/MVR/EQS-N-52-78-69917.pdf
                          > >
                          > > shows most of the output at about 370nm.
                          > >
                          > > However, I think their warm-up times are a problem.
                          > >
                          > > QI lamps will vary their near UV output somewhat according to their
                          > > operating voltage, but unless the mains voltage varies widely, I would
                          > > be surprised if this variation was enough to cause trouble with Riston.
                          > >
                          > >
                          > > - Robin http://www.firstpr.com.au/pcb-diy/
                          > >
                          >
                        • Nuno T.
                          Hi John, Don t have much experience with different exposure lamps to say which one is better, but can give you some solid info on the HF ballasts vs tube
                          Message 12 of 17 , Aug 1, 2012
                            Hi John,

                            Don't have much experience with different exposure lamps to say which one is
                            better, but can give you some solid info on the HF ballasts vs tube wattage:

                            The power supplied by a HF electronic ballast must match the tube power
                            rating. There's a small allowable margin, but less than specified and the
                            lamp either won't light up or will light very dimly and flickering a lot. To
                            much and it will either blow it's filaments or will have a very short life.
                            Using an under rated ballast has no destructive effect that I know of, only
                            the lamp won't give it's full rated light level, if any.

                            HF electronic ballasts don't allow any type of parallel/series connections
                            has it happens with magnetic ballasts for 20W/18W type. There's some models
                            that can run several tubes from the same unit, but they have different
                            connectors for each lamp.

                            eBay has some cheap, and good enough models. Search like: "electronic
                            ballast 18W T8" or "ballast 2x14W T5" (there's no magnetic ballasts for T5
                            lamps, so no need to specify that in the search) Clalight seems to be the
                            best brand for price/performance ratio.

                            Nuno T.

                            > -----Original Message-----
                            > From: Homebrew_PCBs@yahoogroups.com
                            > [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of v321uk
                            > Sent: quarta-feira, 1 de Agosto de 2012 7:51
                            > To: Homebrew_PCBs@yahoogroups.com
                            > Subject: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage
                            >
                            > When buying an HF ballast and fluorescent tube does the
                            > ballast wattage have to match the tube wattage?
                            >
                            > Is it allowable to use an hf ballast of higher wattage that
                            > that of the tube e.g. hf ballast 40W tube 12W ?
                            >
                            > Can you parallel tubes to an hf ballast intended for a single
                            > tube so long as ballast wattage is sufficient ?
                            >
                            > I am building a uv-a light box for sensitised PCB exposure
                            > and am not sure how many tubes to use.
                            > I am thinking get a higher wattage than needed hf ballast and
                            > say two 8 or 12W tubes so if there is insufficient light I
                            > could get one or two more tubes and parallel them.
                            >
                            > I usually use the sun for exposure but there has not been
                            > much of it here over the last few weeks and I need to make a PCB.
                            >
                            > Thanks
                            > John G3UGY
                            >
                            >
                            >
                            >
                            > ------------------------------------
                            >
                            > Be sure to visit the group home and check for new Links,
                            > Files, and Photos:
                            > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
                            >
                            >
                            >
                          • Robin Whittle
                            Hi John, ... The floodlight is a yellow aluminium device with a glass cover and a steel frame for sitting on the ground. It is intended for building sites and
                            Message 13 of 17 , Aug 1, 2012
                              Hi John,

                              You wrote:

                              > Does your 500W halogen connect directly to the mains or does it need
                              > a ballast or current limiter?
                              >
                              > Do you use a base (socket) how do you connect to the bulb?

                              The floodlight is a yellow aluminium device with a glass cover and a
                              steel frame for sitting on the ground. It is intended for building
                              sites and the like. I took the glass cover off and used it for other
                              purposes. This may slightly improve the UV output, but the main reason
                              I did so was because I have mine shining downwards and I wanted to
                              improve air flow around the lamp. I left the wire frame safety guard in
                              place, so it is unlikely that I or anyone else is going to stick their
                              fingers into it while it is turned on.

                              I think these are produced in vast numbers in China, so the same
                              products are likely to be available in most countries, for instance:

                              http://www.jastimber.co.uk/products/electrical/lighting-floodlights/floodlight-portable-500w-fppsl500p-product.html

                              http://quickbit.co.uk/site-lights-task-lights-portable-floodlight

                              http://porlite.en.made-in-china.com/product/BbvECrcTbeYR/China-500W-Portable-Halogen-Worklight-YL1009-.html

                              I paid Australian $16 for mine at the nearby hardware store. These
                              floodlighs use a small tubular filament lamp 119mm long, such as:

                              http://www.lamps-on-line.com/halogen-lights/linear-halogen/standard-linear-halogen/240v-500w-r7s-119mm.html

                              There's no ballast, since it is not a gas discharge tube.

                              - Robin http://www.firstpr.com.au/pcb-diy/
                            • Boman33
                              Preferably keep a fan blowing over your artwork & PCB. The lamp produces a lot of heat- 500W. I am literarily using lamps like that for a specialized heater
                              Message 14 of 17 , Aug 1, 2012
                                Preferably keep a fan blowing over your artwork & PCB. The lamp produces a
                                lot of heat- 500W.



                                I am literarily using lamps like that for a specialized heater to melt
                                plastic. 9 of them mounted side by side in a 3x3 array. 4.5kW!

                                Bertho



                                From: Robin Whittle Sent: Thursday, August 02, 2012 00:07



                                Hi John,

                                You wrote:

                                > Does your 500W halogen connect directly to the mains or does it need
                                > a ballast or current limiter?
                                >
                                > Do you use a base (socket) how do you connect to the bulb?

                                The floodlight is a yellow aluminium device with a glass cover and a
                                steel frame for sitting on the ground. It is intended for building
                                sites and the like. I took the glass cover off and used it for other
                                purposes. This may slightly improve the UV output, but the main reason
                                I did so was because I have mine shining downwards and I wanted to
                                improve air flow around the lamp. I left the wire frame safety guard in
                                place, so it is unlikely that I or anyone else is going to stick their
                                fingers into it while it is turned on.

                                I think these are produced in vast numbers in China, so the same
                                products are likely to be available in most countries, for instance:

                                http://www.jastimber.co.uk/products/electrical/lighting-floodlights/floodlig
                                ht-portable-500w-fppsl500p-product.html

                                http://quickbit.co.uk/site-lights-task-lights-portable-floodlight

                                http://porlite.en.made-in-china.com/product/BbvECrcTbeYR/China-500W-Portable
                                -Halogen-Worklight-YL1009-.html

                                I paid Australian $16 for mine at the nearby hardware store. These
                                floodlighs use a small tubular filament lamp 119mm long, such as:

                                http://www.lamps-on-line.com/halogen-lights/linear-halogen/standard-linear-h
                                alogen/240v-500w-r7s-119mm.html

                                There's no ballast, since it is not a gas discharge tube.

                                - Robin http://www.firstpr.com.au/pcb-diy/



                                [Non-text portions of this message have been removed]
                              • John
                                Thanks Robin, I just realised that I already have one of those stashed away in the garage.... I ll dig it out. John
                                Message 15 of 17 , Aug 2, 2012
                                  Thanks Robin,

                                  I just realised that I already have one of those stashed away in the garage.... I'll dig it out.

                                  John



                                  > The floodlight is a yellow aluminium device with a glass cover and a
                                  > steel frame for sitting on the ground. It is intended for building
                                  > sites and the like. I took the glass cover off and used it for other
                                  > purposes. This may slightly improve the UV output, but the main reason
                                  > I did so was because I have mine shining downwards and I wanted to
                                  > improve air flow around the lamp. I left the wire frame safety guard in
                                  > place, so it is unlikely that I or anyone else is going to stick their
                                  > fingers into it while it is turned on.

                                  > - Robin http://www.firstpr.com.au/pcb-diy/
                                • John
                                  Hi Nuno T, Thanks for the info on ballasts and tube Wattage. I have often wondered whether they need to be matched. Cheers, John From: Nuno T. Sent: Wednesday,
                                  Message 16 of 17 , Aug 2, 2012
                                    Hi Nuno T,

                                    Thanks for the info on ballasts and tube Wattage.
                                    I have often wondered whether they need to be matched.

                                    Cheers,
                                    John




                                    From: Nuno T.
                                    Sent: Wednesday, August 01, 2012 9:54 PM
                                    To: Homebrew_PCBs@yahoogroups.com
                                    Subject: RE: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage



                                    Hi John,

                                    Don't have much experience with different exposure lamps to say which one is
                                    better, but can give you some solid info on the HF ballasts vs tube wattage:

                                    The power supplied by a HF electronic ballast must match the tube power
                                    rating. There's a small allowable margin, but less than specified and the
                                    lamp either won't light up or will light very dimly and flickering a lot. To
                                    much and it will either blow it's filaments or will have a very short life.
                                    Using an under rated ballast has no destructive effect that I know of, only
                                    the lamp won't give it's full rated light level, if any.

                                    HF electronic ballasts don't allow any type of parallel/series connections
                                    has it happens with magnetic ballasts for 20W/18W type. There's some models
                                    that can run several tubes from the same unit, but they have different
                                    connectors for each lamp.

                                    eBay has some cheap, and good enough models. Search like: "electronic
                                    ballast 18W T8" or "ballast 2x14W T5" (there's no magnetic ballasts for T5
                                    lamps, so no need to specify that in the search) Clalight seems to be the
                                    best brand for price/performance ratio.

                                    Nuno T.

                                    > -----Original Message-----
                                    > From: Homebrew_PCBs@yahoogroups.com
                                    > [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of v321uk
                                    > Sent: quarta-feira, 1 de Agosto de 2012 7:51
                                    > To: Homebrew_PCBs@yahoogroups.com
                                    > Subject: [Homebrew_PCBs] PCB light box - hf ballast / tube wattage
                                    >
                                    > When buying an HF ballast and fluorescent tube does the
                                    > ballast wattage have to match the tube wattage?
                                    >
                                    > Is it allowable to use an hf ballast of higher wattage that
                                    > that of the tube e.g. hf ballast 40W tube 12W ?
                                    >
                                    > Can you parallel tubes to an hf ballast intended for a single
                                    > tube so long as ballast wattage is sufficient ?
                                    >
                                    > I am building a uv-a light box for sensitised PCB exposure
                                    > and am not sure how many tubes to use.
                                    > I am thinking get a higher wattage than needed hf ballast and
                                    > say two 8 or 12W tubes so if there is insufficient light I
                                    > could get one or two more tubes and parallel them.
                                    >
                                    > I usually use the sun for exposure but there has not been
                                    > much of it here over the last few weeks and I need to make a PCB.
                                    >
                                    > Thanks
                                    > John G3UGY
                                    >
                                    >
                                    >
                                    >
                                    > ------------------------------------
                                    >
                                    > Be sure to visit the group home and check for new Links,
                                    > Files, and Photos:
                                    > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
                                    >
                                    >
                                    >





                                    [Non-text portions of this message have been removed]
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