Building a UV Box

Gary Hamilton · Dec 15, 2018

Hi Guys
Need help building a UV Box. Just the lights electric etc, I'm ok with the joinery side of things. Where's the best place to buy parts ( UK ).
Should I go with Fluorescent or LED? Will be for Palladium/Platinum.

Thanks

koraks · Dec 15, 2018

I went for Philips UVB tubes which I got online. The quick start ones are best IMO as they reach their rated output within a second or so. Wiring is quite straightforward. Make sure to include a (slow) fuse in the circuit. You can get a cheap Chinese timer circuit on ebay that allows you to set a countdown time in seconds and that switch the lights on and off. Place the tubes fairly close together for even illumination at close distances. Shop around for end caps for the tubes; if you buy these as separate components they're quite cheap and allow placement of the tubes quite close to each other; works better than regular armatures in my opinion which restrict the pitch between the tubes and are far more expensive. Don't forget to buy the correct type and number of ballasts for the tubes you use. I think have something like 8 tubes on two ballasts (2x4). When wiring and testing, keep in mind your ballast will only work if all tubes are connected to it; eg a 4-tube ballast will not start with only one or two tubes connected to it.

Leds are an option but I decided on tubes because of the proven lifetime of tubes, whereas there is debate and some negative experiences with leds in this regard. In terms of energy efficiency, tubes and leds are quite close together. However, UV tubes generally have a spectrum that better suits the needs of most alt processes than leds, which tend to center around 390-400nm while the optimum for most alt processes is usually between 350 and 390nm, so real world efficiency of tubes is generally better than leds.

Gary Hamilton · Dec 15, 2018

Many thanks would you know the best place to buy the parts etc

jeffreyg · Dec 15, 2018

I bought a ready-made light box and use 8 black light fluorescent bulbs. My box has a cooling fan and a hinged door on the front which makes it easy slide the printing frame in and out as well as making test prints and dodging (blind --- can't see because the clearance between the bulbs and print frame is a couple of inches). Also good to have a pair of UV blocking glasses to prevent eye damage if you will be exposing your eyes. This has worked well for me for many years. The first pt/pd images I made was using the sun as a light source and although it comes up every morning it's not so reliable when you might want to print. Right now it is pouring down rain here in sunny south Florida.

http://www.jeffreyglasser.com/

Dan Pavel · Dec 15, 2018

I use a bigger Philips skin tanning lamp (marked as 300w) with 8 UV tubes. I bought it second-hand very cheap in pristine condition. Its timer was not precise enough for my purpose and therefore I installed on it a digital timer relay that fitted perfectly.
The total cost (lamp+relay) was ~ 90$ and it took me a saturday afternoon to fit the timer relay and mount the lamp in horizontal position on the wall.

Timer relay here : https://www.ebay.com/itm/Digital-Ze...h=item2ebe3f73fa:g:nKkAAMXQlrxRa~HJ:rk:3:pf:0

Ian Leake · Dec 15, 2018

UV fluorescent tubes are very convenient and last a long time. I'd definitely recommend them.

When I was in the UK I bought 18W T8 UV tubes here: https://www.lightbulbs-direct.com/product-type/specialist-bulbs/ultraviolet/. You need enough to cover the surface of your print, with centre lines spaced about 5cm apart. The area of the tubes should be larger than the area of the print to avoid fall-off at the edges. Roughly the same distance out from the print area as they are vertically separated should be about right.

The light fixtures you can probably buy from a DIY store, but alternatively here are some RS part numbers (https://uk.rs-online.com/web/):

Ballasts = 714-1420 Check the data sheet to make sure they are the correct wattage for your tubes. These ones support 2 tubes per ballast and have wiring diagrams printed on them.
Lamp Holder = 270-1569 If you buy this style then you will need two per tubes

Make sure you use wire suitable for the current drawn by the tubes. It can get quite hot under the lights and you don't want your cables to overheat. I used 0.5mm2 which is typically rated about 2A. This is overkill for an individual 18W tube but has lasted well with 16 of them.

I hope this helps.

Gary Hamilton · Dec 15, 2018

T

jeffreyg said:
I bought a ready-made light box and use 8 black light fluorescent bulbs. My box has a cooling fan and a hinged door on the front which makes it easy slide the printing frame in and out as well as making test prints and dodging (blind --- can't see because the clearance between the bulbs and print frame is a couple of inches). Also good to have a pair of UV blocking glasses to prevent eye damage if you will be exposing your eyes. This has worked well for me for many years. The first pt/pd images I made was using the sun as a light source and although it comes up every morning it's not so reliable when you might want to print. Right now it is pouring down rain here in sunny south Florida.

http://www.jeffreyglasser.com/

Thanks Jeffery

Gary Hamilton · Dec 15, 2018

T

Dan Pavel said:
I use a bigger Philips skin tanning lamp (marked as 300w) with 8 UV tubes. I bought it second-hand very cheap in pristine condition. Its timer was not precise enough for my purpose and therefore I installed on it a digital timer relay that fitted perfectly.
The total cost (lamp+relay) was ~ 90$ and it took me a saturday afternoon to fit the timer relay and mount the lamp in horizontal position on the wall.

Timer relay here : https://www.ebay.com/itm/Digital-Ze...h=item2ebe3f73fa:g:nKkAAMXQlrxRa~HJ:rk:3:pf:0

Thanks Dan that’s a handy timer

Gary Hamilton · Dec 15, 2018

Ian Leake said:
UV fluorescent tubes are very convenient and last a long time. I'd definitely recommend them.

When I was in the UK I bought 18W T8 UV tubes here: https://www.lightbulbs-direct.com/product-type/specialist-bulbs/ultraviolet/. You need enough to cover the surface of your print, with centre lines spaced about 5cm apart. The area of the tubes should be larger than the area of the print to avoid fall-off at the edges. Roughly the same distance out from the print area as they are vertically separated should be about right.

The light fixtures you can probably buy from a DIY store, but alternatively here are some RS part numbers (https://uk.rs-online.com/web/):

Ballasts = 714-1420 Check the data sheet to make sure they are the correct wattage for your tubes. These ones support 2 tubes per ballast and have wiring diagrams printed on them.

Lamp Holder = 270-1569 If you buy this style then you will need two per tubes

Make sure you use wire suitable for the current drawn by the tubes. It can get quite hot under the lights and you don't want your cables to overheat. I used 0.5mm2 which is typically rated about 2A. This is overkill for an individual 18W tube but has lasted well with 16 of them.

I hope this helps.

Thanks Ian that’s what I need

Ian Leake · Dec 15, 2018

Gary Hamilton said:
Thanks Ian that’s what I need

You're welcome. Jeffryg made a very good point about wearing UV-blocking glasses. These are fairly easy to find online.

Gary Hamilton · Dec 15, 2018

Ian Leake said:
You're welcome. Jeffryg made a very good point about wearing UV-blocking glasses. These are fairly easy to find online.

Yeah will definitely look into it

Gary Hamilton · Oct 11, 2020

Dan Pavel said:
I use a bigger Philips skin tanning lamp (marked as 300w) with 8 UV tubes. I bought it second-hand very cheap in pristine condition. Its timer was not precise enough for my purpose and therefore I installed on it a digital timer relay that fitted perfectly.
The total cost (lamp+relay) was ~ 90$ and it took me a saturday afternoon to fit the timer relay and mount the lamp in horizontal position on the wall.

Timer relay here : https://www.ebay.com/itm/Digital-Ze...h=item2ebe3f73fa:g:nKkAAMXQlrxRa~HJ:rk:3:pf:0

Hi Dan, Ive just got round to assembling my UV box. I did buy the timer you recommended. Would you have a diagram for installing it as the instructions I got are in German Gary

Dan Pavel · Oct 12, 2020

Hi Gary, I don't speak German either. Unfortunately it's a long time since I installed mine and I don't have the English instructions anymore. But it was quite simple. You link the phase wire to 10 and 11 pins and the neutral wire at 12 and get the power for the lamp from the 6 pin and neutral directly from the initial neutral wire.
The device has 6 functions but only the first one is useful for the lamp. In "function 1" to set the time you keep the "up" arrows pressed for a few seconds till the LEDs start blinking and then with the "up" and "down" arrows you set the number of seconds for exposure. When you are done press the start/stop button shortly and the LEDs stop blinking. The exposure value is remembered and anytime you press the start/stop button the lamp will be turned on for the memorased number of sec. If you want to stop it sooner press the "reset" button and the lamp is turned off instantly.
If you press "start/stop" while the lamp is on the timer stops counting-down and "pause" is displayed. If you press it again the timer resumes from where it was stopped.
I have never used the other functions.

Gary Hamilton · Oct 12, 2020

Dan Pavel said:
Hi Gary, I don't speak German either. Unfortunately it's a long time since I installed mine and I don't have the English instructions anymore. But it was quite simple. You link the phase wire to 10 and 11 pins and the neutral wire at 12 and get the power for the lamp from the 6 pin and neutral directly from the initial neutral wire.
The device has 6 functions but only the first one is useful for the lamp. In "function 1" to set the time you keep the "up" arrows pressed for a few seconds till the LEDs start blinking and then with the "up" and "down" arrows you set the number of seconds for exposure. When you are done press the start/stop button shortly and the LEDs stop blinking. The exposure value is remembered and anytime you press the start/stop button the lamp will be turned on for the memorased number of sec. If you want to stop it sooner press the "reset" button and the lamp is turned off instantly.
If you press "start/stop" while the lamp is on the timer stops counting-down and "pause" is displayed. If you press it again the timer resumes from where it was stopped.
I have never used the other functions.

Thanks Dan

Gary Hamilton · Oct 24, 2020

Electrics all done just waiting on hinges for the door and vent covers for fan

Kshaub103 · Oct 24, 2020

I’m planning on building this unit this winter.
http://colinflanarygraham.com/darkshop/?p=337

Gary Hamilton · Oct 24, 2020

Kshaub103 said:
I’m planning on building this unit this winter.
http://colinflanarygraham.com/darkshop/?p=337

that sliding frame looks good.

Thib · Oct 28, 2020

Wow great work!! keeping an eye on your project as I might get started on mine soon

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