Another UV Light Box (16x20) [Archive] - Large Format Photography Forum

denverjims

27-Sep-2013, 06:35

I have been thinking about exploring salt printing for a while and finally have gotten off my duff to begin. One step is to build a UV Light Box. In researching the subject, I have found several good sources from which to steal (ahem, "borrow") ideas - including several here in DIY especially a recent one by jp498. Also, I got a lot of local help from fellow LF'ers Keith Pitman and Jeff Graves.

I finally settled on a 12 bulb T8 design which could accommodate a 16x20 printing frame - more than I think I will ever need but I've been burnt before by not building to an adequate size and having to re-do.

A couple of notes on things I did a little differently than most of the DIY units I saw:

1. I liked the idea of lining the box with reflective material to increase UV effectiveness but rather than use the insulative stuff I found a Nashua product called "Extreme Weather Foil Tape" which is a thick aluminum foil with super hot/cold resistant adhesive. Easy to apply and takes up little room.

2. Rather than buy light fixtures I bought the 'tombstone' light tube holders (Leviton 23351, 60 cents/piece) and I found a ballast which ran 4 lights (Fulham Work Horse WH5-120-L ballast $16.59/piece) requiring only 3 rather than 6 for my 12 bulb unit. The tombstones screwed right onto the board on one side and the ballasts on the other. Wiring was straight forward and I saved some $$.

3. I cut the main board with the lamps & ballasts about 1" smaller than the inside of the box frame and mounted it via L-brackets. This allows the air to be brought up from below evenly around the entire periphery of the light source. Better airflow has meant cooler operation. Mounting the axial fan (Grainger 4WT47) on the top center of the box seemed to work fine.

4. I used 2 switches: one for lights and one for fan. Figured I might want to continue to cool box after lights were out.

Well, after it was all done, I ended up with what you see below.

Front View, door closed
102492

Front View, door open
102493

Board with tombstones attached
102494

Inside detail
102495

denverjims

27-Sep-2013, 08:33

Had a couple of questions so thought I'd reply via post.

1. The shiny stuff under the ballasts is the same Extreme Foil which I put under them to act as a heat sink. The ballasts are marked to 70 C / 158 F and, while not enough to ignite wood, thought I'd be better off with spreading heat around.

2. I was asked how the fan was mounted so am including the picture below.

3. The ballasts are instant start type so that's why I chose the shunted tombstones.

4. & yes, in addition to pizza you can also do "Hot Pockets". :>)

View showing fan mounting & wiring
102500

davehyams

27-Sep-2013, 09:09

This looks like a great project, what do you estimate the total cost to be? Are you going to make your own contact frame as well? have fun salt printing, its a really fun process

d

Vaughn

27-Sep-2013, 09:20

I noticed you used a BLB tube. They work fine. The BL tubes are the same, but without the internal visible light filter, thus cheaper.

The manufactured units I have seen used cross ventilation instead of the top. I suppose both work equally well...I know the cross ventilation pulls air across the ballasts fairly well, and if yours are electronic, they might not heat up as much as the conventional. The main advantages of the cross ventilation is that I am always putting stuff on top of the unit...the disadvantage is having to keep the unit's sides clear (can't shove it in a corner).

Nice work! Vaughn

denverjims

27-Sep-2013, 10:49

D,
Thanks, it was interesting and I think I learned more about UV light printing and functionality by doing the research to design. Plus it was kind of fun. Hadn't done a project like this in too long.

I figure that the entire cost was about $390. But I made a couple of choices which increased costs by choosing to use cabinet grade plywood and brass fittings. Also, I bought BLB bulbs instead of BL because my Home Depot had a 'deal' on them due to an overstock. However, I probably could have saved even more if I had shopped for BL's. They are less expensive/bulb.

I found an 11x14 Formulary frame on Craigs List pretty reasonable so did not build. If/when I go 16x20 will definitely build unless I can score a similar deal.

denverjims

27-Sep-2013, 11:02

Vaughn,
Thanks, & you are right about BLB's being more expensive but found some at a discount which made it closer to BL price.

Thought about ventilation issue cross/vertical. These ballasts are instant start electronic - from my research better and more reliable than the magnetic - but are still marked as potentially getting to 70 C. I guess I was more concerned with getting air evenly out of the exposure compartment which is why I went with this design. Too much heat can cause sensitized salt paper to brown based on my readings.

I designed with 2 1/2 inches of space from ballast top to fan bottom distance and, with the heat sink aluminum under the ballasts figure that will be better circulation than if they were inside a standard light fixture. Fan has 130cfm capacity and the entry for air at bottom is 6"x9".

Top vs. side: - potato - potaato (I hope).

102502

29-Sep-2013, 04:53

denverjims

29-Sep-2013, 08:49

Looks great! (perhaps better than mine)

Mine doesn't get hot. I don't worry about it getting hot. The printing frame is FAR cooler than when I printed with a metal halide light. My case fan isn't very powerful. It would probably be fine without a fan, but I prefer it to run cool.

Thanks jp,
As I said, your unit gave me a good start in design. Had to tinker though. I guess that's what we do...

Jim

denverjims

29-Sep-2013, 14:44

I figure that the entire cost was about $390.

Sorry, that should have said $290.

Jim Graves

29-Sep-2013, 17:53

Congratulations ... Really nice design and well executed. Thanks for posting it.

Where did you get the light sockets ... and what are the part numbers or relevant.specifications?

denverjims

29-Sep-2013, 20:17

Congratulations ... Really nice design and well executed. Thanks for posting it.

Where did you get the light sockets ... and what are the part numbers or relevant.specifications?

Thanks Jim. 1000Bulbs.com. Search site for 'Levton 23351'. Note that it is for instant start type electronic ballasts like the Fulham I used. A different type ballast (like programmed start [& I think rapid start]) need a non-shunted 13351.
Jim

polyglot

29-Sep-2013, 21:30

Lovely build.

A note about the ballast temp though - that 70C specification is the max case temperature that they can survive and is absolutely no indication of how hot they will actually get nor does it say anything about the heatsinking required. The actual temperature attained is a function of not only how much power they dissipate but also how you heatsink them. If you put them in a sealed box, the temp will climb past 70C and they will fail sometime after it goes above 70C. If you put them in a well-ventilated box, they will probably stay within 10C of ambient.

If you can find out the thermal resistance of something (often printed with a theta symbol, and in units K/W that's kelvins per watt) then you can compute the exact temp rise from the dissipated power.

For a power supply like this, the power dissipated in the supply is = Load_Power * (1 - Efficiency) / Efficiency

For example with a 90%-efficient ballast driving 3x40W=120W of bulbs, Pdiss = 120 * 0.1 / 0.9 = 13.3W.

And say the ballasts have a thermal resistance of 1.2 K/W junction-ambient, then the internals of the ballast will be 1.2 * 13.3 = 16K (16C) above the air temperature that they're immersed in. Say it's a nasty 40C day with an infinite supply of fresh air (this doesn't happen; see below), the ballast will reach 56C, which being less than 70C, is acceptable. If you can find the thermal resistance value, you can determine whether additional heatsinking (and how much) is required.

Similarly, you can compute the flow rate of air required to keep the box internals below a certain temperature. Taking the heat capacity of air (1kJ/kg-K) and density (1.15 kg/m3 at 35C), you can figure out the fan capacity required. Say this box is dissipating 400W of power in total (bulbs and power supplies) and we want to keep the air exhaust within 10C of ambient, that means we need 0.4/10 = 0.04kg/sec of airflow, which is 0.035m^3/sec, or 35L/sec = 2000L/min = 74cfm, which corresponds to a fairly powerful 120mm fan running with NO restriction. You will need more fan than the specifications indicate, because the flow rate drops once you put it in a box and have to drag air around corners and through little holes.

So we have 35C air being inhaled and heated to 45C, which is then used to cool the ballasts. They're going to be 16C above ambient, which is now 61C; still acceptable.

If you get a bad answer (devices exceeding their thermal spec), adjust airflow rates and/or heatsink thermal resistances until you make it work.

denverjims

1-Oct-2013, 07:30

A note about the ballast temp though - that 70C specification is the max case temperature that they can survive and is absolutely no indication of how hot they will actually get nor does it say anything about the heatsinking required. The actual temperature attained is a function of not only how much power they dissipate but also how you heatsink them. If you put them in a sealed box, the temp will climb past 70C and they will fail sometime after it goes above 70C. If you put them in a well-ventilated box, they will probably stay within 10C.

Thanks for the explanation. Given that ballasts are enclosed in a small space in a fixture, I understand better now why fixtures are all metal. The fixture is a big heat sink necessary to keep ballast cool enough.

As to the calculations, I was able to follow some of that. I guess I got lucky as my exit air is not very hot so ballasts must be OK. My design was close enough to others, though, that I figured I would not smoke the ballasts or my house.
Jim

Jody_S

1-Oct-2013, 07:41

Thanks for the explanation. Given that ballasts are enclosed in a small space in a fixture, I understand better now why fixtures are all metal. The fixture is a big heat sink necessary to keep ballast cool enough.

Jim

Fixtures have to be designed to withstand a catastrophic ballast failure without starting a fire or injuring a building occupant.

It was common, with magnetic ballasts, to have to have gasoline or paint thinner on had when working on fluorescent fixtures, because every 3rd or 4th ballast had overheated to such a degree that it had leaked insulating tar all over the inside of the fixture. You needed a solvent-soaked rag to clean up before moving on to the next one.

polyglot

1-Oct-2013, 21:07

Thanks for the explanation. Given that ballasts are enclosed in a small space in a fixture, I understand better now why fixtures are all metal. The fixture is a big heat sink necessary to keep ballast cool enough.

Yep, and folded sheet metal is really cheap for mass-manufacturing purposes.

If you leave it on for an hour then power it down and have a feel of the ballasts, it should give you some idea. Say you test on a 20C day, add 15C to get the performance on a 35C day and if that answer is still OK, your build will be fine.

Also, running the air over the ballasts before the tubes will result in lower ballast temps since they dissipate only a small fraction of the heat.

Robert Brazile

30-Nov-2013, 06:48

Just a note to say that I built my own light box using Jim's as a model and am happy with the result. The build generally went well, despite a short moment of panic when I popped the circuit breaker as a result of a stupid wiring error with the switch. Slept on it, had a good think over a cup of tea in the morning, and realized my idiotic mistake. Put it right and all worked fine. Haven't put it into action yet -- have to pour some carbon tissue first -- but am really looking forward to it.

http://farm8.staticflickr.com/7456/11122484353_d262a925ae_z.jpg (http://www.flickr.com/photos/rbrazile/11122484353)

http://farm6.staticflickr.com/5493/11122382264_c916d533b6_z.jpg (http://www.flickr.com/photos/rbrazile/11122382264)

http://farm8.staticflickr.com/7410/11122494453_7f56903593_z.jpg (http://www.flickr.com/photos/rbrazile/11122494453)

Jim, thanks very much for publishing your results.

Robert

Cletus

30-Nov-2013, 10:39

It sure is nice to see some great ideas circulating around and people using the info to build these (really nice) UV boxes. Back when I was contemplating building one myself, I kinda lucked into a ready-made Edwards Engineered box, which serves my needs fine. Certainly, had I gone down the DIY route, all this information would have been invaluable - especially polyglot's inspired knowledge of some of the power, temp and flow calculations required if you really wanna do it right!

Thanks Jim, Robert and Polyglot for posting all this great info (all of which is going straight into my little "UV Printing" archive) for those interested in the process, or thinking about putting one of these boxes together.

BTW - Sandy King published a very thorough and comprehensive study on Unblinking Eye pertaining to various UV sources and their use with various alt processes. It's a great read and something I'd highly recommend looking over if you're interested in this area of photography.

Here's the link: http://unblinkingeye.com/Articles/Light/light.html

30-Nov-2013, 11:13

Looks great Robert!

Tin Can

30-Nov-2013, 11:37

Great, but I need it today. My partner is coming to try Carbon, we have the Sun, cold Sun.

Thanks for all the info, OP and everyone.

Robert Brazile

30-Nov-2013, 12:20

Thanks, all.

JP, meant to call you out as well, as I started on this path by looking at your box first, then when Jim posted his, took that into account also. It's so helpful to have the examples shared here to give guidance when embarking on one of these projects. Thanks to all who do so.

Robert

denverjims

1-Dec-2013, 13:22

Just a note to say that I built my own light box using Jim's as a model and am happy with the result. ...

... Jim, thanks very much for publishing your results.

Robert

Nice job, Robert.
Glad that a few of my ideas seemed to work out for you; but like Cletus indicated, it's very much a group effort here.
And don't worry about the wiring error, I'm pretty sure that circuit breakers were invented for amateur 'electricians' like us. :>)
Best of luck on your Carbon Project, Jim

williaty

23-Aug-2016, 19:48

If either of you are still subscribed to this thread, did you use the F25T8 tubes that are ~17" long for this build? I'm having a hell of a time figuring out what ballast to use with those tubes. If you guys are running F25T8s off the Fulham Work Horse WH5-120-L, then I'll just do that as well.

Robert Brazile

24-Aug-2016, 08:03

I'm still around, but have forgotten the details. I'll look when I get home.

Robert

Robert Brazile

25-Aug-2016, 17:26

OK, managed to dig up the old order. They are the 18" tubes, but not F25T8, mine are F15T8 BLBs driven by Fulham Workhorse 5 WH5-120-L ballasts. Hope this helps.

From a product description I managed to find with Google: "The EIKO 15526 F15T8/BL is a preheat fluorescent bulb optimized for ultraviolet output at 350 nanometers, a wavelength within the UVA blacklight spectrum.

This 15 watt lamp results in 2.6 watts of ultraviolet at the target wavelength. The bulb is 18 inches long with a 1 inch diameter and a G13 medium bipin base.

Applications for the F15T8/BL include insect traps, curing and photo enlarging."

Robert

denverjims

27-Aug-2016, 05:15

I used the Fulham Workhorse WHS-120-L for my build, as I said above, because the specs said they'd work fine and drive 4 bulbs as opposed to 2, thus limiting costs.

Also, the BLB choice was that they had the right spectral output and I found a deal on them (my Home Depot was trying to cut stock). My understanding is that normally these would not be the least expensive alternative. I think someone said that BL's might be spectral-ly fine and normally less $$$.

Best, Jim

Justin.williams

27-Jun-2017, 04:55

A big shot in the dark on this one, but does anyone know the dimensions used for the uv box in this post? Sorry to revive old threads.

denverjims

28-Jun-2017, 06:48

A big shot in the dark on this one, but does anyone know the dimensions used for the uv box in this post? Sorry to revive old threads.

Exterior:
Width: 26 5/8" Depth: 22" Height: 13 3/8"
Interior:
Width: 25 1/8" Depth: 21"

Let me know if you need more info, Jim

Justin.williams

28-Jun-2017, 11:36

That's awesome. Thank you very much. I appreciate it.

sheel

15-May-2019, 23:30

Hi, I'm in the process of building a UV box - would someone be able to help me validate my circuit diagram? I messed up in my original design and ended up blowing through a few ballasts ($$$ lesson).

I'm using similar components to those in this build thread -
* Terminal Block (1) [600v, 30amp]
* SPST Rocker Switch (2) [125vac, 16amp]
* Fulham WH-5 120V Ballasts (3) [120vac, 1.15amp]
* F25T8 UV Tubes (12) [25 watts]
* Leviton 23351 T8 Shunted Tombstones (24)
* Grainger 4WT47 Fans (2) [115vac, 0.18/0.21a, 18/20 watts]

I'm concerned about -
* The switch and the power delivered to the ballasts,
* The two independent circuits sharing the same "out" (Switch 1. Lamps + Ballasts, Switch 2. Fans). If I calculate this properly ~300-360 watts will be on Switch 1 and ~36-40 watts on Switch 2.

Also, once a fuse is blown on the Fulham ballast, are they replaceable/repairable? I opened up one of the ballast cases and it's covered/sealed in silicon.

191364

Jeff T

16-May-2019, 01:19

Jim Fitzgerald

16-May-2019, 10:24

This is a great read. I've been using my NuArc 26-1ks for a long time now and would like to have a backup unit incase I have to travel to do a carbon workshop or demo. Nice job guys thanks for the info.

sheel

16-May-2019, 16:59

I would recommend an isolation transformer between the wall and your appliance, 120VAC input and 120VAC output while you're testing the design. I would also install an IEC receptacle with a fuse but-in or install a fuse just after the power receptacle. The switch is rated at 16amp, each ballast draws 1.15amp, and there are 3 ballasts, the fans draw insignificant amount, so you're not anywhere near exceeding 16amp rating of the switch. Why not use a DPDT switch so the fans come on automatically? A cheap ballast could have poor overload protection and would blows itself up if the load is not connected, imbalance load, or high side shorted to ground. Perhaps use a ballast with a better warranty. Do not open the ballast, it's probably beyond your level.

On the schematic, why are the switches connected to neutral?

Thanks for the feedback Jeff.

1. Isolation transformer - makes sense for protection - would a surge protector suffice, or are you referring to full on power conditioner?
2. IEC receptacle - this is a great idea; i was trying to figure out how to add fuses - something like this receptacle (https://www.amazon.com/dp/B071H7X2XG/ref=sspa_dk_detail_4?pd_rd_i=B071H7X2XG&pd_rd_w=DMhOH&pf_rd_p=8a8f3917-7900-4ce8-ad90-adf0d53c0985&pd_rd_wg=fS6Ho&pf_rd_r=F8KG885D9K8652TFZVD3&pd_rd_r=ce4cde55-787d-11e9-a967-b34187462b23&th=1) should be appropriate?
3. DPDT could make sense, I just kind of went with two separate switches on a whim while I was at Home Depot, as to control the lights or fans separately. They're these nice little rocker switches (https://www.homedepot.com/p/Gardner-Bender-16-Amp-LED-Illuminated-Round-Hole-Rocker-Switch-GSW-50/205971618).
4. These Fulham ballasts are supposed to be pretty high quality (?) and even have an internal fuse... unfortunately they're sealed and not self-serviceable... Agree, I will stay away from cracking them open. No point. I definitely blew the first one with a poor connection and the second because a staple I used penetrated the return wire :|
5. Switches connected from Neutral to Ground - this could be a mistake, the last time I had all the switch connected from neutral to white/out one of the three ballasts went out. There is an LED light on the switch itself which needs power, and this does not come on if I don't have Neutral connected to Ground or Out.

Let me know if you have any other advice... I'm an electrical n00b

denverjims

17-May-2019, 08:17

3. DPDT could make sense, I just kind of went with two separate switches on a whim while I was at Home Depot, as to control the lights or fans separately. They're these nice little rocker switches (https://www.homedepot.com/p/Gardner-Bender-16-Amp-LED-Illuminated-Round-Hole-Rocker-Switch-GSW-50/205971618).

I did find having separate switches was helpful. Could leave fan (I only used one) on after turning off lamps to dissipate heat faster after long exposures.
Best, Jim

sheel

17-May-2019, 12:02

I did find having separate switches was helpful. Could leave fan (I only used one) on after turning off lamps to dissipate heat faster after long exposures.
Best, Jim

Thanks Jim, would you be able to comment on your general circuit design vs. my approach? I'm not sure if I'm on the right path or doing something completely off - here's the current schematic.

191399

Jeff T

17-May-2019, 12:06

The isolation transformer is to protect you from excessive current if you touch the black wire. Without the isolation transformer, your body completes the circuit to ground when you touch the black wire.

If it's a LED lighted switch then the Neutral lead is for the LED circuit. Update your schematic to show the LED so there's no confusion. Having a separate switch for the fans poses a great chance for overheating. Perhaps using a DPDT with a heat sensor to activate the fans would be more elegant.

Thanks for the feedback Jeff.

1. Isolation transformer - makes sense for protection - would a surge protector suffice, or are you referring to full on power conditioner?
2. IEC receptacle - this is a great idea; i was trying to figure out how to add fuses - something like this receptacle (https://www.amazon.com/dp/B071H7X2XG/ref=sspa_dk_detail_4?pd_rd_i=B071H7X2XG&pd_rd_w=DMhOH&pf_rd_p=8a8f3917-7900-4ce8-ad90-adf0d53c0985&pd_rd_wg=fS6Ho&pf_rd_r=F8KG885D9K8652TFZVD3&pd_rd_r=ce4cde55-787d-11e9-a967-b34187462b23&th=1) should be appropriate?
3. DPDT could make sense, I just kind of went with two separate switches on a whim while I was at Home Depot, as to control the lights or fans separately. They're these nice little rocker switches (https://www.homedepot.com/p/Gardner-Bender-16-Amp-LED-Illuminated-Round-Hole-Rocker-Switch-GSW-50/205971618).
4. These Fulham ballasts are supposed to be pretty high quality (?) and even have an internal fuse... unfortunately they're sealed and not self-serviceable... Agree, I will stay away from cracking them open. No point. I definitely blew the first one with a poor connection and the second because a staple I used penetrated the return wire :|
5. Switches connected from Neutral to Ground - this could be a mistake, the last time I had all the switch connected from neutral to white/out one of the three ballasts went out. There is an LED light on the switch itself which needs power, and this does not come on if I don't have Neutral connected to Ground or Out.

Let me know if you have any other advice... I'm an electrical n00b

denverjims

18-May-2019, 15:27

Having a separate switch for the fans poses a great chance for overheating. Perhaps using a DPDT with a heat sensor to activate the fans would be more elegant.

Jeff, I didn't understand this unless you meant that it would be possible to turn on the lamps but not the fan with 2 switches. Technically, I agree but felt that low risk. I turn fan on first and don't turn it off until I'm done with my entire printing session and things have cooled down.

Heat sensor would be more elegant but also more stuff to buy and wire. I was using KISS and figuring if I did not turn on the fan, I'd deserve the consequences. Being a Libertarian, it fit right in with my personal beliefs. :)
Best, Jim

18-May-2019, 15:32

If the fan is running, it is unlikely to ever heat up, so it the fan goes on and off with the light that's simple and practical too.

denverjims

18-May-2019, 15:34

Thanks Jim, would you be able to comment on your general circuit design vs. my approach? I'm not sure if I'm on the right path or doing something completely off - here's the current schematic.

191399

Looks good to me (although my lawyer would suggest a more cautious response to avoid liability if you blow yourself up, I'll ignore that).

As you noted, miswiring the ballast to the lamps is the biggest risk but the ballasts usually have a wiring diagram for how they are to be used with the lamps. If it is not printed on the top of the ballast, then look the ballast designation up on the web and usually you can find wiring specs. The only other thing, as I noted in my original post, is to choose the correct 'tombstone' for the type of lamp and ballast combination you are using.

Best, Jim

denverjims

18-May-2019, 15:44

If the fan is running, it is unlikely to ever heat up, so it the fan goes on and off with the light that's simple and practical too.

Correct, jp, but since many alt printing process chemistries are sensitive to heat as well as UV, I decided to have a way to keep the fan on after lights went out since the lamps continue to put out heat after turning off. That way I don't have built up heat from the last, long exposure inside to start off with the next one.

Frankly, I was not sure that this would be real problem (and still am not). Many other designs I've seen do not have 2 switches so others don't think so. Maybe they are right but that was my choice and it seemed a cheap enough up front add-on to be insurance against that kind of problem. Retrofitting a second switch after the fact (if I had found it was an issue) would have been a pain.
Best, Jim

Tin Can

18-May-2019, 15:55

Perhaps some use an external timer to turn it off.

denverjims

18-May-2019, 17:38

Perhaps some use an external timer to turn it off.

Good point, Randy, as I think I'd be more apt to forget to turn the fan off after I'm done rather than to forget to turn it on when I'm starting to print. But you'd either have to mount a timer switch for the fan circuit instead of a simple on/off one; or add a second plug for the fan power and, as you said, an external timer.

Again, I enjoy KISS-ing more. I'll leave the autopilot stuff to Tesla. :)
Best, Jim

sheel

18-May-2019, 22:42

Looks good to me (although my lawyer would suggest a more cautious response to avoid liability if you blow yourself up, I'll ignore that).

As you noted, miswiring the ballast to the lamps is the biggest risk but the ballasts usually have a wiring diagram for how they are to be used with the lamps. If it is not printed on the top of the ballast, then look the ballast designation up on the web and usually you can find wiring specs. The only other thing, as I noted in my original post, is to choose the correct 'tombstone' for the type of lamp and ballast combination you are using.

Best, Jim

Thanks Jim.

Yeah, I went by the Fulham wiring diagram found here - https://www.fulham.com/WDpdf/wire7.pdf. The ballasts and bulbs work when I went direct to AC. Unfortunately, when hooking everything up (excluding the 2nd circuit with the fans) something in the circuit keeps causing the ballast's internal fuses to blow. I suspect it's either the switch (??) or the wire connectors (e.g. too small, poor connection).

This is the switch I've been trying to use - https://www.homedepot.com/p/Gardner-Bender-16-Amp-LED-Illuminated-Round-Hole-Rocker-Switch-GSW-50/205971618

I changed the wire connectors from WT3 to WT6 which are larger - max 2 #14 gauge wires (WT3) vs. max 4 #12 gauge wire (WT6).

So, I went to Home Depot today and bought these Phillips ballast (4 lamp, instant start, electronic)- https://www.assets.lighting.philips.com/is/content/PhilipsLighting/f2823915b7464a2a9a11a49d00bfc884

I eliminated the switch from the circuit and wired these up directly to AC on the terminal block, with the power plug going to a surge protector - all 3 ballasts and 12 bulbs worked as expected, nothing blown/shorted. Btw, these ballasts don't have an internal fuse, and also I have not yet connected up the fans (e.g. the 2nd circuit).

So, I'm not sure what the heck is going on.

If I wire back in a switch, I'm either going to get an IEC receptacle with fuse-in, or get an in-wire fuse to protect the load size of the switch - probably 5 amp fuse.

Tin Can

19-May-2019, 00:21

I don’t like the looks of your original switch.

Looks cheap.

Beware of Trojan Horses.

I would not use an internal switch at all.

External timer switch or use household wall switch in a standard steel electrical box with grounding bolted to the box.

What is the box made of?

Most lamp containers are grounded metal.

Install GFCI in any Darkroom and use it.

sheel

20-May-2019, 03:30

Ok, so I've updated my schematic - I'm up and running with the ballasts/lights. I've yet to wire up the fans - will keep you guys posted on the final.

* Using the Phillips REB-4P32-SC ballasts instead of the Fulham WH-5-120L
* I've soldered in a 5 amp fuse on the hot wire coming into this circuit
* Eliminated the switch on the circuit and will use a surge protector to switch on/off

191440

denverjims

20-May-2019, 09:16

sheel

20-May-2019, 14:07

sheel,
I just used a standard household wall rocker switch for each circuit and had not had any problems with the Fulham's I used. As far as the ballasts were concerned, any brand should be OK once wired properly. The main thing for me was that they were the first ones I came upon which required only 1 ballast to drive 4 bulbs, like the Phillips ones you found.

You changed more than one thing so it's hard to tell what the issue was. Others might be better to judge but I don't believe the 14 vs 12 gauge wire would make a difference. I'd guess that it could have been a bad ballast, or, as Randy said, maybe the switch. At any rate, the important thing was that you are up-and-running. Adding the fan circuit should be no problem given the low additional load. Good job sticking with it.
Best, Jim

Thanks Jim!

Yeah, many components changed in my scheme. Since about 3-4 ballasts blew at different times, it's highly unlikely to be ballasts.

As for the wiring change - that was specifically the connector, going from a smaller one that is only meant for 2 #14 wires to a larger one that can take 4 #14 wires - I suspect a poor connection.

The switch itself is rated at 16 amps on 125 vac - hard to believe a switch rated for these specs would've caused the issue. As far as I know, a wall switch is not much different than this switch. Not sure how to rule that out w/o blowing fuses, but a moot point now that I've got a scheme up and running.

Very thankful for this thread and others that have helped me! I'll be writing up a blog post too on this schematic once I'm done.

drewf64

5-Jun-2019, 11:13

Hello Jim:
I have been reading through your UV light box posts with great interest ... great build and information share!
I have been making albumen prints recently using a natural light mixture of direct sun & clear blue northern sky.
Everything goes well when the light is perfect. However, I have only had two printing sessions with great light allowing for 6-12 minute exposures.
So ... a couple of questions:
* You referenced salt printing in one of your posts ... have you printed on albumen?
* What have the exposure range lengths been with your box?
* Would the UV output be any different between classic salt and albumen?
THANK YOU!!
Drew

Robert Brazile

9-Jun-2019, 05:10

Can't speak for Jim, but I've done a fair bit of salt and albumen printing with mine. 20 minutes is not unusual (mine was based on one of Jim's designs, has a bank of 12 fluorescent BLBs) but of course it depends on the negative and the particular sensitization formula you use. It's the usual story: print until it looks good, then print a bit longer. If the border starts solarizing/turning metallic looking, you're pretty much there.

Exposures should be roughly the same for salt vs. albumen; after all, it's basically the same process, just with some underlayment in one case, so to speak.

Robert

denverjims

9-Jun-2019, 15:37

... a couple of questions:
* [1] You referenced salt printing in one of your posts ... have you printed on albumen?
* [2] What have the exposure range lengths been with your box?
* [3] Would the UV output be any different between classic salt and albumen?

Hi Drew, Sorry for the delay but was 'out of the evil influence of the internet' last week.

In answer to your questions:

1. 'No' on Albumen, but from what I've read, I believe that Robert is correct and Salt and Albumen times could be similar.

2. Anywhere from 15-25 minutes, varying on the look I've been trying for and the negative density I was using. I shoot 4x5 film negatives, scan, then process with Photoshop. Finally print out using transparency material. Correct on having edge begin to turn to indicate when it's near done. But like in enlarging times, a lot of your exposure times will depend on the look (density) you are trying for and the density of your negative you are trying to print through. Also varies with the silver concentration of your paper coating (for more on this - which might pertain to Albumen as well - see Ellie Young's publications on the Salt printing process - she has a published book and her thesis for her RMIT graduate work as well.)

3. Not sure what you mean here. The UV output is what it is. It is independent of what is underneath. If you meant to ask if the effect on Albumen prints is different than Salt, then I'd guess not a lot. But others who have done both would be better suited to answer that question (as in #1).

Hope that helps and glad that this thread has been useful. As I said in the beginning, I used a lot of ideas I had found in some previous builds, so just trying to pay-it-forward some.
Best, Jim

drewf64

10-Jun-2019, 07:01

Hi Drew, Sorry for the delay but was 'out of the evil influence of the internet' last week.

In answer to your questions:

1. 'No' on Albumen, but from what I've read, I believe that Robert is correct and Salt and Albumen times could be similar.

2. Anywhere from 15-25 minutes, varying on the look I've been trying for and the negative density I was using. I shoot 4x5 film negatives, scan, then process with Photoshop. Finally print out using transparency material. Correct on having edge begin to turn to indicate when it's near done. But like in enlarging times, a lot of your exposure times will depend on the look (density) you are trying for and the density of your negative you are trying to print through. Also varies with the silver concentration of your paper coating (for more on this - which might pertain to Albumen as well - see Ellie Young's publications on the Salt printing process - she has a published book and her thesis for her RMIT graduate work as well.)

3. Not sure what you mean here. The UV output is what it is. It is independent of what is underneath. If you meant to ask if the effect on Albumen prints is different than Salt, then I'd guess not a lot. But others who have done both would be better suited to answer that question (as in #1).

Hope that helps and glad that this thread has been useful. As I said in the beginning, I used a lot of ideas I had found in some previous builds, so just trying to pay-it-forward some.
Best, Jim

Hello Jim:

Off the grid last week? Nice place to be !!
Thank you for your reply ... greatly appreciated!

In my question about exposure ranges ( I should have said times ) I was just looking for a comparison between time using the Sun vs. the light box ...
eg. The box times are 1.5x times as long, 2x the time, etc.

Re: Your comment to my question #3 =
I should have been more clear.
What I was trying to ask was ...
Is the "best" UVA wavelength different for Salt vs Albumen?
Because I need to choose BL vs. BLB tubes.
USHIO offers BL @ 352nm and BL & BLB @ 368nm.
A 16nm differential is splitting hairs and perhaps inconsequential.
But since I need to choose ... would one be better for Albumen vs. the other?
Again ... thank you.
Drew

drewf64

10-Jun-2019, 07:07

denverjims

10-Jun-2019, 07:41

Drew,
I had seen builds using BL as well as BLB. I had not remembered hearing/reading that one was better by any substantive amount. I think I said that my decision was based on finding a deal on the bulbs I used. They seem to be adequate.
As far as sun vs box, I never used sun. My understanding is that, even at our altitude, the box beats the sun by a fair amount. I'm getting old and did not have the time to wait for the sun. :>)
Best, Jim

Jim Noel

10-Jun-2019, 08:57

Robert Brazile

10-Jun-2019, 12:49

Yes, the sun is generally faster, assuming it's not 4PM on a winter's day. :-)

As to Drew's questions: I'm unfortunately on the road again today, so can't go peek at my unit and give you the specific specs. A photo of the underside of the unit, which may help, is here: https://flic.kr/p/hWR7Ks

I'll look at it again when I get home to refresh my memory. I will say that I never did know the exact frequency profile of the lights but to date I never have needed to. The bulbs came from Home Depot; I haven't seen them there in a while, so they may not carry them any longer, but I expect can be ordered easily enough. I believe they were intended as aquarium lighting.

The archives of the carbro list may have some information on the bulbs; I originally built the unit to do carbon printing (and it works fine for that) and Sandy Moss has mentioned his findings in testing these there a few times...

Robert

drewf64

10-Jun-2019, 14:03

Robert:
Thanks for the photo. Looks to be one inch diameter tubes and this matches the specs for T8 in your photo and the other descriptions in this thread.
17.xx or 18 inches long depending on which manufacturers' ruler we use!
I am now shopping around for the best deal on BL or BLB tubes as it looks and sounds like the 352nm vs. 368nm UVA wavelength issue is a NON-issue.
As much as I would prefer to use the sun, if I can get predictable and repeatable light output from the box I will be very happy!
Again ... Thank you.

Jim & Jim:
Thank you for your replies ... appreciated!

Drew
Drew

denverjims

11-Jun-2019, 07:37

...
As much as I would prefer to use the sun, if I can get predictable and repeatable light output from the box I will be very happy!
...
Drew

I guess I had the wrong understanding about the sun vs box re: speed. But, frankly, the factors you just mentioned would have had me go to the box anyway. Not to mention the fact I can print in the evening or on heavy overcast days.
Best, Jim

11-Jun-2019, 07:48

With the sun, you can guess or use an integrator to measure exposure as brightness and UV changes. Quick bright exposure will work different than slow gradual exposure; the slow exposure will self-mask to a certain extent and have a slightly different contrast at least with cyanotypes as the coating changes color and starts to reverse with time part way through the exposure. As such I think an indoor exposure box is most predictable. Perhaps run it for a minute before using it to make sure the bulbs are all up to temp and happy. When I print, it's usually bad weather outside or 9-11pm (after the kids are in bed.)