MY DIY film drying cabinet

My previous drying cabinet was a hanging clothes garment bag, instructions found here. Although it works, it has a few flaws. One is it's not tall enough for 35mm film, another is you have to unzip it and sort of use your elbow to open it and hope that your negatives don't touch the zipper or stick together as your trying to get them hung up. The thing also moves around because of all that and causes the whole thing to swing and potentially causing your film to touch. Then there is the rough service bulb that I hope I never dropped film onto, etc etc.

Doing more research led me towards this Ikea Detolf display cabinet. I went to take a look at it and thought it had potential so was all set to buy it. Problem was, I took my car and it wouldn't fit. And it's 45 minutes to the store so I wasn't about to go get a truck. Glad that it didn't work out because I found something better.

My local Orchard supply hardware store has these Keter four shelf cabinets, the same of which are I found cheaper at Amazon (The price shows up at $77.00 with free shipping). I have prime so it may show shipping if you don't have prime. EDIT: I found that if I search for "keter four shelf cabinet" the price shows correctly with free shipping. You have to scroll down the page to see the cabinet after you search. I also had a Jobo Mistral 2 that I just won on Ebay to mount on top.

Advantages seem to be several. Plastic so it won't rust. You can use duct tape to seal it up and it's really light when you want to move it. Another advantage is that you can actually fit a roll of 36 exposure 35mm film with out bending it or it touching the bottom. There may be cheaper ways to do this, but I found this a nice combination of cost vs. time spent putting it together. Oh, the top and bottom snap together which means that you can actually fit the box in your trunk...And if you have Amazon prime it's free shipping :-D

Still not sure if I need an exhaust fan, there is a slight gap at the front doors, maybe 1/16" when closed which I hope is enough to provide some positive air pressure while letting out enough air to keep the fan running correctly.

You should have the same square inches for letting the air out as you have to let the air in, in order for this to operate properly.

fotch said:

You should have the same square inches for letting the air out as you have to let the air in, in order for this to operate properly.

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So just a hole with no exhaust fan?

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nbagno said:

So just a hole with no exhaust fan?

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You don't need to have exhaust fans also. The point is you need to give the air going in a place to go out. Having the same amount of square inches for the air to leave as the same amount of square inches as the hole letting where air comes in all owes for proper airflow.

I personally would do a series of holes around the bottom that added up to roughly the same size as the hole for the fan on the top.

You must use a lot of film, that's a great big cabinet.

Light Guru said:

You don't need to have exhaust fans also. The point is you need to give the air going in a place to go out. Having the same amount of square inches for the air to leave as the same amount of square inches as the hole letting where air comes in all owes for proper airflow.

I personally would do a series of holes around the bottom that added up to roughly the same size as the hole for the fan on the top.

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I saw a post that lead me to a film drying cabinet manufacturer that used an exhaust fan which is why I considered it.

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nbagno said:

I saw a post that lead me to a film drying cabinet manufacturer that used an exhaust c an which is why I considered it.

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SMBooth said:

You must use a lot of film, that's a great big cabinet.

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No bigger than any others I have seen.

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An exhaust fan will speed drying, but a drying cabinet with airflow will work fine. The last place I used one with an exhaust fan was in a newspaper darkroom.

MattKing said:

An exhaust fan will speed drying, but a drying cabinet with airflow will work fine. The last place I used one with an exhaust fan was in a newspaper darkroom.

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Good to know. I will try curtin in a vent hole with a louver.

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Light Guru said:

You don't need to have exhaust fans also. The point is you need to give the air going in a place to go out. Having the same amount of square inches for the air to leave as the same amount of square inches as the hole letting where air comes in all owes for proper airflow.

I personally would do a series of holes around the bottom that added up to roughly the same size as the hole for the fan on the top.

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Why a series of holes?

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It looks good to me!

Jeff

nbagno said:

Why a series of holes?

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So that there are not places that don't have good air flow.

Your air in fan is on the top, for if the air out take was on the bottom the floor would block it. If the air out take was on the right side in the middle then the air current would go from the top to the right side middle. Any film on the left would not dry as well and film that hangs longer then the middle would dry well on the upper half but not the lower half. If the air out hole was on the bottom right film on the left would not be touched by the air current.

SO if you had a series of holes around the bottom that totaled about the same size at the intake on the top then the. You would have enough ventilation for air not to build up inside and the air flow would be consistent in all parts of the cabinet.

Think about the cabinet like a wind tunnel.

Light Guru said:

So that there are not places that don't have good air flow.

Your air in fan is on the top, for if the air out take was on the bottom the floor would block it. If the air out take was on the right side in the middle then the air current would go from the top to the right side middle. Any film on the left would not dry as well and film that hangs longer then the middle would dry well on the upper half but not the lower half. If the air out hole was on the bottom right film on the left would not be touched by the air current.

SO if you had a series of holes around the bottom that totaled about the same size at the intake on the top then the. You would have enough ventilation for air not to build up inside and the air flow would be consistent in all parts of the cabinet.

Think about the cabinet like a wind tunnel.

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By on the bottom I meant "towards the bottom" thinking on the rear wall at the bottom. I get what your saying.

Ned

nbagno said:

By on the bottom I meant "towards the bottom" thinking on the rear wall at the bottom. I get what your saying.

Ned

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Don't just put the holes on the back against the wall. The wall will block proper airflow unless you have it out from the wall a bit.

Light Guru said:

Don't just put the holes on the back against the wall. The wall will block proper airflow unless you have it out from the wall a bit.

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It's not pushed against the wall now but could be in the future. Hole on the sides would work.

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If you have dust then a plastic pipe and laundered muslin rag allows a filtered air solution.

The internal diameter needs to be just larger than film.

Feed in film with close pin weight from top hang pipe over table lamp (on floor,) muslin at bottom held on with elastic band.

Suitable for students in shared bathroom apartments.

I'm thinking of building a film drying cabinet for a community darkroom. Here's my thoughts; feedback appreciated.

Initial thought is to use an off-the-shelf utility cabinet like this. Similar to the OP's cabinet, but bigger. I could build a simple cabinet, but the off-she-shelf approach is faster. Might even be able to find a used metal office cabinet.

Rather than an exhaust fan, I plan to use a 4" inline duct fan or bathroom exhaust fan to push air into the cabinet at the top. The fan will operate on a timer and the air intake into that fan will be filtered. The door will latch shut (but not sealed) and I'll add exhaust vents at the bottom. The reason for "pushing" air in is to create positive pressure and therefore less worry about dust entering.

For filtering, haven't settled on approach. Could be as simple as cloth or a vacuum cleaner bag taped to the end of 4" duct. If using an exhaust fan, could be as simple as cloth or filter material taped (gaffers tape) over the intake. If I wanted to get fancier, I could build a box that would tightly fit a vacuum hepa filter. A dryer lint trap box might be a short cut.

Thoughts?

mgb74 said:

I plan to use a 4" inline duct fan or bathroom exhaust fan to push air into the cabinet at the top.

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I suspect you will find a bathroom type fan will blow too much air through. A couple of computer case fans would proably be more appropriate with the added advantage of being low voltage. You won't need much air movement in a small cabinate to dry the film...

nbagno said:

I saw a post that lead me to a film drying cabinet manufacturer that used an exhaust fan which is why I considered it.

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Military and UPI darkrooms had film drying cabinets with build in heater and a fan, the fan. One had to be careful about setting the temperature as it was possible to overheat the film, and there was a filter that needed to changed. Unless you are in a real hurry I would avoid a fan and the possibility of brining in additional dust.

Good points.

paul_c5x4 said:

I suspect you will find a bathroom type fan will blow too much air through. A couple of computer case fans would proably be more appropriate with the added advantage of being low voltage. You won't need much air movement in a small cabinate to dry the film...

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There is a surplus electronics place near me with all types/sizes of "muffin" fans. It wouldn't take much to build a filter box to attach to it on the input side.

PDH said:

Military and UPI darkrooms had film drying cabinets with build in heater and a fan, the fan. One had to be careful about setting the temperature as it was possible to overheat the film, and there was a filter that needed to changed. Unless you are in a real hurry I would avoid a fan and the possibility of brining in additional dust.

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There is a related questions about how best to dry film quickly without damage. In my personal darkroom, I just hang it up. But in a community darkroom, it would be nice to have it dry faster. I want to avoid heat (for a couple of reasons) but an easily changed, inexpensive filter isn't a problem.

Those military and UPI darkrooms were quite content to sacrifice some negative quality/longevity for speed. So were newspaper darkrooms. I suspect there are some "tricks of the trade" that others here know about.

I too was thinking some variety of computer equipment fans would be more suitable. There are (were?) some that run off AC mains power and are very quiet and "gentle" -- I think you only need a modest air circulation. In my distant past I have used two lightbulbs in series so they run way below normal brightness and last forever as a heat source too. (But I've never built a film drying cabinet, I was using a homebrew thing to dry coatings.)

After using this cabinet it was apparent that I don't need the heating element turned on, at least in the moderate Bay Area. I just use the fan, drys in an hour plus or minus.

I could start with one fan, then add a 2nd if necessary. I like the idea of film drying in approximately an hour.

A 120mm computer case fan would work. Maybe one on each side at the top with vents at the bottom for a cabinet that is about 48" wide. What's also nice is that I can source pre-made filters and finger guards.

But why? As someone noted, you must have a LOT of film to dry at once. Which implies that you process a LOT of film at once.

I find that a clean microfiber cloth, twice over, and maybe ten minutes hanging even in my humid climate pretty well does it. I guess if the presses were being held for me , there's the old hair dryer.

I have more worries with flying particles (aka dust) glueing to emulsion rather the drying time.
And it is also why we would look for a good idea of DIY cabinet.