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Nitrogen System for Dust Removal and Chemical Preservation

Many thanks, everyone, for your advice. As far as I can see, only PE uses this approach, with the rest of you kindly sharing the pros and cons. I was rather hoping it was more popular amongst APUGers, who'd share specific model names/types for a nozzle etc, but I'm happy to browse a catalogue.

@PE: any chance of a photo of your nozzle if you have it handy? feel free to PM.

Just to address a few other helpful points raised: I was not planning to use the nitrogen cylinder quite in the manner shown in the linked videos.

Dust Off is expensive here, running about $20+/can for the namesake or $30 for Kenro Kenair, which in my experience, is the best as it does not spew the super-cold ejaculate too often—only from time to time. Shipping those cans from abroad is nigh on impossible due to air restrictions, so I spend a minor fortune on it and I wish to save—the outlay on a full nitrogen system, even if it came to $300, is likely to pay back quickly.

Many thanks for the suggestions about clamping it upright. I will definitely not have it indoors, it would be outside of the building, behind darkroom's wall, with pipework and an appropriate tap indoors.

Bob: I fully agree with your observation about compressor systems that carry oil and moisture, which is why I have been using Dustoff/Kenair, while the Irish humidity is thankfully helping a lot.

Clive: It is clear to me that my negatives benefit from a little air blown over them, but I am also investigating a static/ionising Kinetronics vac-brush at present (I wish I could get the old Kodak one). If you do not use either, please share how do you remove dust from prints during dry-mounting. With a glossy print surface almost anything will scratch it. I have found air to be the best.

To those who like the rubbery bulbs, I admire your physique—using a bulb during a print mounting session seems to require Hulk's grip.
 
I bought a small cylinder of nitrogen and regulator from a craigslist seller a couple of years ago, I use it for chemical preservation but not dusting. The guy I bought it from serviced color processing equipment and the nitrogen was used to pressurize the chemistry plumbing and eliminate air in the machines.

I've not found a really convenient valve for dispensing a small amount especially for a dusting sort of application, I use a sort of cobbled up arrangement of a small stop valve and some plastic tubing which is not pressurized most of the time.
 
I was surprised at how far dust off actuallly goes, if your darkroom or setup room is clean and humid,and you have very good workflow for setting up your negs, all you need is a simple blast from the
side to close the glass holders.
 
I will try to photograph the valve, but right now can't get the time. I'm pretty much tied up with some other things.

PE
 
Rather than nitrogen, is it possible to get a tank of argon gas, using a similar setup?
 

Despite all the doomsday scenarios mentioned, I also have a small tank of nitrogen I use for displacing air in chemistry containers. I don't use it for dusting off negatives. It's a small tank, only stands about 18" tall. I bought it, the regulator and hose at a local welding supply shop. It wasn't very expensive.
 

I did the same. If I recall, the welding dealer remains the owner of the tank, and if I need a refill, they just exchange the tank. Also, I think the tanks only can be used for so long and if not certified or whatever, they cannot be filled so they are loaned/leased to the customer.
 
You can indeed buy or lease any gas tank. If you lease it, you pay what is called "demurrage", or a monthly cost for the container.

Less expensive tanks and small tanks require periodic inspection, but AFAIK the large professional tanks do not. At least I have never seen that requirement exercised. I have seen it with the small tanks.

They come in different sizes, pressures and threads. They also come in different colors denoting the gas contained within. All of these must match.

PE
 
All the pressure tanks are stamped with a test date and need to be pressure tested every few years, that's why the large ones are usually rented out. The expense is covered by the rental fees and the tanks are cycled through as they are returned for filling.
 
Here typical N2 tanks must be checked at an authorized workshop every 10 years. This includes disassembling of the valve and inner inspection of the tank, pressure test, valve test etc.

Located at private premises no-one would check the dates. But at the next filling the check would be necessary anyway.
 
Interesting. All of the small ones (3 ft or 1 m and under in height were except acetylene). The large ones have no date. I grew up in literally rooms full of incoming and outgoing tanks, both owned by our family company and rented.

I have several of the owned versions here. I'll have to take another look.

PE
 

Have you tried soapy water to find the leak. Wet the hose with it and you should get bubbles where the leak is.
 
Bob Carnie said:
I was surprised at how far dust off actuallly goes, if your darkroom or setup room is clean and humid,and you have very good workflow for setting up your negs, all you need is a simple blast from the side to close the glass holders.
Click to expand...

My experience too.
 
I don't pay any monthly or yearly rent on the tank. When I need to refill the tank, they will exchange it and I will pay then, for the gas & rent?
 
I used 2300 psi large tanks of N2 everyday testing car engines. We needed an inert gas. Cost of the gas is minimal. PE is correct as usual. Chain the tank upright to something very solid, always have a steel safety cap fully screwed on whenever you move a cylinder and for photography purposes you will be using very low pressure and volume.

I think running the line through a wall is a very bad idea. You want quick access to the main tank shutoff valve. All regulators must be very heavy duty and specific to the N2 application. Welding supply shop territory.

I would empty a large tank in 10 minutes in a small test room, but kept the doors open and ran an exhaust fan to avoid N2 saturation of the breathing air. I was using test pressures up to 1000 psi.

However, I worried more about the automatic Halon fire extinguishers...
 
Thanks, but I forgot to mention the safety cap. They are a must! I also agree about going through a wall, but I had no option.

PE
 
There's no reason to have oil, dirt or moisture in any air line. You install in-line filters for that kind of problem. A good compressor can be used for all kinds of things and is overwhelmingly the most cost effective and reliable method for dealing with routine film, camera, and paper
cleaning issues. But that's the catch - buy a good one to begin with, not some silly toy from Sears or Home Cheapo.
 
A compressor won't give you inert gas for topping containers to eliminate oxidation. Dust off or dry nitrogen is needed to displace the air. If you can avoid ignition sources, a propane torch could be used to top containers (just don't use the igniter) but I'm not sure what the sulfides in the gas would do to your chemistry. Nitrogen is inexpensive as far as welding gases are concerned and a small tank carefully used can last a very long time.
 
I can't comment on using nitrogen to blow dust off negatives and such, I use a Kostiner 5" brush and that seems to do fine. But for those using nitrogen to displace air in chemical bottles, why not simply use a wine vacuum pump and the associated rubber stoppers? Evacuates the air without all the complications of a nitrogen system, and is inexpensive. I'm doing that with developer, I don't worry about the other chemicals (primarily fixer and selenium toner).
 

Pete, a brush will scratch glossy prints being dry mounted. Wine pumps do not evacuate much air at all, plenty remains inside, they merely slightly reduce its pressure. If you did use real vacuum, you'd need special closures, special bottles, and you'd find that some liquids would boil off under real vacuum.
 
I don't believe that you can remove all the air plus, I found uses for the nitrogen, such as storing paint. Getting air out of a paint can & sealing it would be a bigger problem than just replacing the air. My wife uses some very small cans of expensive paint (she restores reverse glass paintings) and then the larger cans of paint or stain used for house maintenance or furniture restoration. JMHO
 
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