Dust Update

jmoche

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A few weeks ago, I posted looking for advice to reduce the amount of dust and other grime that keeps showing up on my negatives. I got lots of good advice, but it didn't seem like I was ever going to find a suitable dust-free environment in which to hang my freshly developed negs. I decided to Google DIY film dryers. A lot of different designs showed up, but one in particular caught my attention because of its simplicity and cost. I got everything I needed at Amazon and Home Depot. It's basically a tube with an exhaust fan at the bottom, a HEPA filter at the top, and a rod inside to drop film reels onto. I opted against adding a heating device. Yes, I do have to deal with some pretty significant curl, but after sleeving, a hour or two under a stack of books seems to do the trick. Here's what my dryer looks like.






 

jay moussy

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I believe there is at least one other DIY dryer proiect in the forum archives, and was discussed at length. There were issues, as I vaguely recall.
I may be helpful to look it up?
 

jtk

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'Hilarious sculpture, nice work, looks great. Better replace that fan with a DC fan (surely available online), rather than risk electrocution.
 

albada

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One PVC-pipe film-dryer deserves another. Mine is for 35mm film. HEPA-filtered air enters the bottom via a hacked hair-dryer, and leaves the top, so dust cannot fall into the top while film is drying.


That large HEPA-filter is overkill, but it's what Home Depot had in stock, and I didn't think of buying a smaller one online. The long vertical pipes are not glued to the bottom, they are held by friction, so they can easily be removed for transport or storage. I removed the heater from the hair dryer, and run its motor using a 5v or 12v DC power-supply, so it provides a gentle breeze up the pipes. Humidity here is about 50%, and film dries in 30-45 minutes.

Drying film in this leaves no dust on the film. None.

Mark Overton
 
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jmoche

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I like the design. I though about something similar, but I shoot a lot of 120, and even 3" pipe would be too close for comfort for me. Enough 4" pipe to hold an entire roll would be large. That HEPA filter looks a lot like the ones Home Depot sells for my Shop Vac
 
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jmoche

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jay moussy said:
I believe there is at least one other DIY dryer proiect in the forum archives, and was discussed at length. There were issues, as I vaguely recall.
I may be helpful to look it up?
Click to expand...

The design inspiration came from a dryer that was posted on this site. And, yeah, I'm sure issues are going to crop up. Right now, though, I am happy as a clam. I've finally managed to get a few rolls developed that don't have dust permanently embedded in the emulsion.
 

albada

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Dusty Negative said:
I hate when that happens.
Click to expand...

Thanks for the laugh. I know that some people like grain, but you're the first one I've met who likes dust! You must hate these dust-free dryers.

jmoche:
| That HEPA filter looks a lot like the ones Home Depot sells for my Shop Vac

You nailed me!
 

albada

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Could you post the specifics of the components that went into your dryer? While my dryer is fine for 35mm, I'd like to shoot some 120, and I have everything I need except a film dryer. I'm thinking of copying yours. The parts I'm interested in include:

Type and size of HEPA filter​
Round plastic ring securing the filter​
Square plastic holder between the fan and pipe.​

Your use of a sewer-pipe tee was clever. It smoothly directs air around the 90-degree turn and into the pipe.

I'm thinking of eliminating the center rod and turning the whole dryer upside down, which would allow me to mount the dryer on a wall. The filter would be on the fan, which would blow air into the pipe, from top to bottom. The bottom would be open. I would feed reels into it from the bottom, and hold them using a thin steel rod that would slide horizontally through two opposite holes in the pipe, preventing the reels from falling out. Do you see any problem with this design?
 
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jmoche

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Here's a link to the HEPA filters. I chose these because they fit perfectly into a standard coupling used to connect two pieces of 4" PVC to one another:


The square plastic holder between the fan and the pipe is a square drain that fits into a 4" PVC pipe. It just happens to be the right size for a 4" fan. I got mine from Home Depot. Your best best is to take the fan you buy to Home Depot and check different drains until you find one that fits. The other alternative is to buy an inline fan that will connect to the PVC with standard ducting.

It sounds like you're planning to have the reels sitting horizontally inside of the pipe. Mine are sitting vertically, so that the air basically flows through the reel. I don't know if it will work as well if the air is hitting the film surface head on, especially for the film on the opposite side of the reel. Your idea to load the reels from the bottom is a good one. When I want to load film reels, I have to disassemble the whole thing. If you want to go back to the long rod idea, you'll have to come up with a way to attach it to the top of the contraption. A thin strip of wood or a metal bracket attached to the inside of the pipe just under the fan would probably work.
 

albada

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jmoche said:
Here's a link to the HEPA filters. I chose these because they fit perfectly into a standard coupling used to connect two pieces of 4" PVC to one another:
Click to expand...

Could you post the link as simple text? There's a bug in Photrio that causes links to appear blank. Internally, your link was translated to this:
leftbracket MEDIA=amazon rightbracket B093VPTCXC leftbracket /MEDIA rightbracket


I changed my mind. I think I'll put the fan on the bottom as you did, and insert the reels from the top, with air flowing through the reels like yours.
To avoid disassembling it, I'm thinking of putting the filter on the bottom (so air flows upward through the pipe), and inserting the reels using a lifter-wire as is used in tall tanks.
To use, I would first stack the reels on the lifter-wire on the counter, and then, carrying that stack-of-reels by holding the top of the wire, insert the assemblage down into the pipe.
Sound feasible?
 

MattKing

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albada said:
Could you post the link as simple text? There's a bug in Photrio that causes links to appear blank. Internally, your link was translated to this:
leftbracket MEDIA=amazon rightbracket B093VPTCXC leftbracket /MEDIA rightbracket
Click to expand...
 

albada

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Matt, I just discovered this: The link displays fine in Chrome, but in Firefox 103.0 (running on Linux Mint), there's just a blank area there. That's true of both posting #11 and your reply in posting #13. I've seen this problem in other links too. It's something Sean should be told about.
 

MattKing

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Does Firefox 103.0 depict Youtube links correctly?
I ask, because Amazon links do show up as "Media"
 

DREW WILEY

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Two basic problems relative to improving the setup next time around. Plastic pipe is electrostatic, so attracts dust, possibly even sparks. Every owner of a woodshop which hasn't burned down yet knew that in advance. And static-resistant pipe can be purchased even from woodworking hobby suppliers like Rockler. Alleged HEPA home filter air-purifying devices are better than nothing, but are not classified as true HEPA systems because dusty air gets around them. You won't find the real deal at Home Depot or anywhere analogous, and it will cost way way more. But if someone needs true room air purification without spreading dust past seals, or rather, lack of seals, it can be done. And no, you can't find true HEPA vacs in those places either, despite misleading advertising claims. That fact makes a huge difference if you actually try to vacuum fine dust in a darkroom or inside an enlarger without just shooting it out the exhaust end of the vac itself. The alternative is to keep the vac completely outside the room and just bring the hose in. But in this relatively simple film drying application, even a basic fine mesh "permanent" coffee filter would help.
 
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albada

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Electrostatic charge on plastic pipes will pull dust out of the air and onto the pipes, reducing dust on negatives. In fact, you can buy electrostatic air cleaners that operate on this principle. In any case, humidity is about 50% all year where jmoche and I live (SoCal), so there won't be much static charge.

I examined the seals on the Ridgid vac-filter on my film-dryer. They consist of rubbery plastic that was covered with a layer of glue, onto which the filter material was placed. I think that will effectively prevent air from bypassing the filter. You can see the seals clearly in my 2nd and 3rd photos. The fact that both jmoche and I are seeing no dust on negatives verifies that our HEPA filters are sealed well (or maybe there's high static charge on our pipes ). Please provide links to documentation about poor seals.
 

DREW WILEY

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Rigid vacs per se are cheapo construction shop vacs with zero hepa seals. That requires a two stage system isolating the motor from the vacuum system itself. But if you've improvised your own seal using caulking style sealant, that's a real asset. Static danger will be present if your the rate of air going through there is too fast, and the film already dry. At least the film is already developed, so you won't risk permanent static discharge marks on the image itself.

And don't think the humidity is too high in your area for a spark problem. I'm up here on foggy SF Bay, and just about every shop I can think of that illegally used standard PVC or ABS pipe for dust extraction burned down long ago. No kidding. I've outfitted more shops than I can count, and sold more true Hepa vac systems per year than anyone else in the US, even carried an EPA license for awhile related to safety certifications. Now retired, thank goodness.

One real simple trick is to ground your pipe with a long strip of aluminum foil adhesive tape, and then a length of speaker wire off from that to ground. But in your case, I don't anticipate much risk because you won't be pulling or pushing air with serious force. I worry more about someone taking this concept and putting it on steroids with a more powerful fan, or adding a heater, where the risk increases. Hence the need for at least a token warning.

Incidentally, I have a true industrial electrostatic air cleaner which actually deionizes the air coming out. You can get little desktop versions of those cheap. But this is a big lifetime duty thing containing many septa of large copper plates, and would be awfully expensive to make today. It was salvaged out of a defunct sound studio where everyone smoked, and then given to me free. The plates were simply soaked in detergent and all the nicotine and grit came off. No plastic in the whole thing except for the switch. But I did once make my own little sheet film drying cabinet using very simple components just like you have.
 
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albada

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Drew, I like your idea of using aluminum foil tape to drain static charge to ground. But I'm afraid much of it would stay on the plastic, unless the entire pipe were covered with foil. What do you think of an ESD coating/paint such as this one?:
LICRON CRYSTAL ESD SAFE COATING
The idea is that this coating would transfer all charge to the foil.

By bad experience, I know that static electricity is a serious matter with electronics, and that we have plenty of it on us even when do not feel shock when touching something grounded. Despite my light remark earlier, I want all static gone, even just for a film dryer.
 

MattKing

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jmoche

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The lifter wire is a good idea. If your fan is on the bottom, you'll want to be sure that the reels remain above the part of the pipe that the fan is connected to. If you're thinking about leaving the top open, you should probably get a cap to cover the pipe with when the unit's not being used to keep dust from getting in. If you were never able to get to the Amazon link, just search for GL2103 Hepa replacement filter.
 

gone

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I taped up the vent and window in the bathroom, making it simple to load film and hang negs in there. If you run the shower enough to get the room steamy, then quickly hang the negs and shut the door, there's no way for dust to get on anything. Any dust will already be soaked and clinging to the wet areas. There won't be any floating around in the air, and there's no way for new dust to come in. I've never had issues w/ dust in the negative emulsion using this method.
 

DREW WILEY

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albada, the point is to ground the inside of the tubes with that metal tape. I'm not familiar with the exact brand of antistatic spray you posted, but the kind I've used has been very effective on things like plastic film holders and darkslides, and has numerous potential darkroom uses too. One caution with regular plastic drain pipe is the presence of residual contaminants when its new; so not only flush out with water first, but scrub everything with alcohol before assembly or applying antistatic spray.

If you peruse a catalog or website of a true cleanroom supplier you discover a lot of things, some of which are affordable and practical, others perhaps a bit too deluxe and expensive for a home darkroom. I did build my own cleanroom, separate from the sink and chemistry room, which can be completely sponged down in advance of any really tricky film work. Nowadays it's hard to find static resistant paint which dries fast and doesn't very slowly outgas like oil-based paints do., Most acrylic or latex paints are themselves rather electrostatic. One really helpful item is a true 100% dacron cleanroom smock or lab coat. These are lint free, very durable, and I think I last paid about thirty dollars for one from McMaster Carr.

Makeshift clean areas can be sectioned off from other portions of the darkroom with simple temporary polyethylene sheet dividers like painters use to isolate rooms. If you go that route, just make sure the ventilation is adequate so humidity and mold doesn't become an issue. If the area is small enough, simple desktop air purifiers can be quite effective at reducing fine dust or lint in the air.
 

Chuck1

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I actually used to hang film to dry in the bathroom,
I ran the shower hot for a little while,
this steamed up the room (with the window closed)and knocked down the dust
never had problems after that
 
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