What kind of timer for your UV light box?

guruguhan

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Hi everyone,

I'm using an HID light source for alt printing and would like help on getting a timer for it. Would like to keep it under $100 and if it could handle more than one device it would be great (but not essential).

Any help is appreciated.
 

ann

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we are using a gralab 300
 

bill schwab

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Get an old Gralab timer off ebay. I've gotten them as low as $10.00. Problem with HID is wam-up time though. At least it was with my old rig. It took a good 5-10 minutes before that unit was running at full output. Hard to use the timer to start and stop the light. In my case I had to let the light warm-up, then place the printing frame and set the timer.

Bill
 

sanking

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When using an HID lamp a warm-up of at least 5-10 minutes is essential when using a plain timer.

Platemakers use a timer which is based on light integration and measure the light in units. With an integrator you just turn on the unit and when the necessary number of units have been reached, it turns the lamp off. Stand-alone integrators, which have been made by Olix and NuArc among others, can sometimes be found on ebay in the Graphic Arts section.

Sandy
 

bill schwab

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sanking said:
Platemakers use a timer which is based on light integration and measure the light in units.
Click to expand...
I would have loved to have found one of these when using my HID system! Definitely the way to go if you can find one and it is affordable.

Bill
 
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guruguhan

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Is the photocell part of the integrator? Are there different integrators where the photocell is connected by a cable or something? If the photocell is part of the integrator, where should it be placed (right next to the frame? - will I need to compensate for light falloff at the edges?)

If I get a used integrator, is it a good idea I buy a new photocell for it (do these age)? Thanks for the info everyone!
 
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guruguhan

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I've been reading a bit more on these...have a couple more questions. Sandy...what's your current distance between print and the tip of the bulb? On unblinking eye, I think you said 20"? I read elsewhere that you place your photocell 25" from the tip, on a wall. Does this mean that your print to bulb distance has changed to greater than 25"? I'd like to have a setup that allows me to print to 16x20" without needing to change the level of the light (I've posted another thread on the swinging center filter). I'm not sure about what height I should mount at (I was initially thinking 20" and using a filter as you describe for larger prints).

If I get a used integrator that doesn't come with a photocell (or any other accessories other than a cable connector) - will I be able to find the other things I need easily?
 

sanking

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Hi Gu,

I am no longer using the HID lamp you see in my article at unblinkingeye as I sold it to someone on this list a couple of years back, complete with vacuum frame and integrator. It was a very nice exposing unit, easily equal in speed to a NuArc 261k I replaced it with.

However, I think the ideal distance from tip of lamp to surface of prnting frame is about 40". I was using 20" at the time I wrote the article, with a diffuser, because of limited vertical distance in my working space. However, I did have some uneveness of exposures that was eliminated by removing the diffuser and increasing distance to 40".

Sandy
 
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guruguhan

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Thanks a lot Sandy. Do you know where I might be able to find a PA710D photocell for Olec integrators? How much should these go for (just the photocell).
 

sanking

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guruguhan said:
Thanks a lot Sandy. Do you know where I might be able to find a PA710D photocell for Olec integrators? How much should these go for (just the photocell).
Click to expand...

Olec still sells photocells that work for UV output, not sure about that one. You won't see them sold separately very often on ebay. In fact, some of the integrators are sometimes sold without the sensor, which makes them pretty much useless until you find a cell.

Sandy
 

mark

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Why don't you leave the light on and remove the frame when a digital timer goes off? Turning an HID light on and off over a short period of time will shorten its use life.

I print with one of two 1000 watt bulbs. One in a Hydrofarm reflector and the other in a DIamod Luminarc reflector. The one I use, depends on which one is not growing veggies in my classroom garden. I print at about 40 inches. I use a digital timer to tell me when to pull the printing frame from under the light. Works just fine.
 

mark

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And the lettuce too. This was the best crop I have had in a long time. Fifty two kids and the staff at the school I work at had great salads at harvest time. And yes the Basil was good. What nutrients are you using? I used Above and Beyond Grow for my lettuce and basil. I had basil leaves as big as my hand. It was cool. I switched to FLora Nova for my second round and things did not go so well in the lettuce department but the Chiles were phenominal.
 

bill schwab

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mark said:
And yes the Basil was good. What nutrients are you using?
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It was Hy-Gro I think. I believe it was a local Michigan company. It has been some years since I've had time for the set-up and I do not know what is available anymore. I was doing this in the end of the 80s - early 90s, so I am sure the technology has grown if you will pardon the pun. I loved doing it as a hobby. The growing room I set-up was a real treat to spend time in the dead of a Michigan Winter. Smelled like Summer with veggies, flowers, etc. Someday when there is time and space I will do it again.

That 1000 watt lamp made a great plate burner until I went to the BL bulbs. I used to keep it about 30 inches above the priting frame and it was pretty even light.

B.
 

donbga

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sanking said:
Hi Gu,

I am no longer using the HID lamp you see in my article at unblinkingeye as I sold it to someone on this list a couple of years back, complete with vacuum frame and integrator.
Sandy
Click to expand...

I'm the someone that purchased the HID from Sandy. The unit is setup in my garage and is about 37 inches above the vacuum easel, whic is mounted on a table that can be moved for more compact storage. It's been a while since I have used the lamp since my garage is in shambles now due, to what seems to be a never ending house remodeling project. I hope to have all of that cleared out again this fall.

The HID works very well with the Olix integrator. The most difficult part of the setup for me was calibrating the timer, making 1 unit of exposure equal to 1 second. One of the accessories I don't have for this unit is a timed control relay that will allow the vacuum easel to draw down before the lamp is powerd on.

I'm sure you can contact Olix and inquire about a timer/integrator.

Good luck,
 
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guruguhan

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Thanks Don,

After reading the manuals to a few integrators, I'm seeing that the maximum outputs are only around 200-250watts. I'll be using a 1000watt MH though. I did a search for a solution on this and guess what...I ran into yet another posting by Sandy. In it, Sandy said he used a "relay". I'm a dummy, what is a relay (I've done a search but dont know what to get), solid state or electromechanical?, how difficult is it to install? This would go between the integrator and HID I presume? What kind of specs am I looking for when buying a relay?
 

donbga

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Normally we think of a relay as an electro-mechanical device. Simply put, the output of the timer energizes a coil of wire which creates a magnetic field. THe field has enough force to cause a spring loaded plunger to move "or close" which will complete an electrical circuit energizing the lamp. As long as the relay coil is turned on by the timer, the lamp stays on.

The probe, sensitive to UV light, is connected of course to the timer. After the probe receives enough UV energy the timer is satisfied and de-energizes the relay, turning off the lamp.

To make things simple you can go to an electric supply house and explain to them what kind of device you need. THey can sell you the appropriate relay.

Of course I presume you unserstand how to wire all of this together. Not difficult really. For safe use you will need some type of simple box to enclose the relay. You can purchase this at the same place you get your relay.

Hope this helps,
 
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guruguhan

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Hey Don,

That does help, thanks. I know the probe (you're referring to the photocell right?) is connected to the timer/integrator - I was asking where the relay fits in. Between the integrator and light yes?

I'll just ask at the local electrical supply house for the type of relay I'll need. Thanks again

Gu
 

donbga

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On my Olix integrator there us a standard 3 prong AC outlet (250 watts - 5 amps.) that should be connected to the input side of the relay. Another AC line should be connected to the relay ON contact lugs of the relay. The lamp is conneted to the output lugs of the relay. When the relay is energized the circuit of the source voltage for the lamp is closed and juice flows to the lamp through the ouput lugs. All the integrator does is supply power to the relay, not the lamp.

The probe is placed on the easel facing the light source and is plugged into the timer/integrator. The probe has an adjustable aperture which can be used to attenuate light if necessary (sort of a crude sensitivity adjustment) The timer has potentiometers that can be adjusted to calibrated the probe to the light source.

To calibrate the timer properly the lamp needs to come up to full output. Olix has documentation that you can download for free that explains the calibration procedure.

Good luck,
 

sanking

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That is correct. The integrator is connected to the power supply, and in turn has a outlet for power to the light source. What you do is run the power from the integrator into the relay, and then from the relay to the light source. The relay that I made for the unit that Don bought from me is a very simply electro-magnetic relay that I placed in a box of the proper size.

Sandy
 
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