Automated Emulsion Making - more modern formulas
I have been following the thread on using stepper motors for emulsion making and have been rather surprised at the number of people who want to get into it.
I don't have the financial resources to do this type of work, but I would be willing to whip up some sort of 'manual' or 'tutorial' along these lines. I would also be willing to set up some sort of advanced workshop if anyone is interested and if we can find the equipment and lab to do it in.
I'm trying right now to locate a simple epoxy syringe with two plungers and two tubes to try a controlled delivery of silver and salt, as you have gotten my interest up on this. I could imagine it being done by hand even. I hesitate using one that has already had epoxide in it, as such a 'used' syringe may contaminate the silver or salt.
I've been sitting here running double run, pseudo control emulsion formulas through my head all afternoon thinking of ways to simplify this sort of make and how to automate it.
I've also been contemplating a large scale (1 KG) run of the Azo type emulsion using a heavy duty mixer that I have here. I've just never given a thought to making one that big and you have gotten me curious. It took me about 5 100 gram runs to get one that worked when I first started. Now it scales just fine, but I'm curious. I have always stopped at 600 G.
So, is anyone interested? If so, I may put some ideas down on paper, otherwise with just 2 or 3 interested, it will have to wait until I get a better film emulsion with my current formulas.
Just for starters, I'll throw out some intriguing ideas....
Make a small run, say 100 grams of a concentrated emulsion.
Dilute it with lots of gelatin and salt and then run in a second batch of silver in a second run over top of it for a total of 500 Kg.
This way you make your 'seed' emulsion, and then grow on top of it with totally different conditions. BTW, this is nothing new, but does take a bit more control and darkroom manipulation. It also moves us from the 20s-40s into the 50s-60s. I've been staying away from this type, as I was trying to duplicate the early century emulsions, but interest seems high enough in more modern makes so I thought I would put the idea forward.
Bigger batches and more modern (50s-60s) formulas are possible, and with simple control may be very interesting.
Count me in!!!
I am definitely interested. I have a machinery dealer friend who sometimes comes across pharmaceutical / food grade stainless steel machinery and equipment. He buys all or parts of companies that use this equipment and resells it, pieces at a time. I will ask him to keep an eye out for any small to mid size items that would be applicable here.
I think 60cc syringes (no needles) should be available over the counter at a surgical supply store, maybe even online, but I'll have to check on that. I don't know offhand of a source of unused dual epoxy dispensers, but I will look around.
I came across an interesting web site that describes syringe pumps that are closed loop, and do not necessarily require a PC for control. I don't know if the device is appplicable, but cost notwithstanding, it gives you ideas. Take a look here: http://www.syringepump.com/NE-16001800.htm
If a 1 kg run of the Azo emulsion was produced, you could possibly adapt Jim Browning's coater almost as it is, to produce large sheets for cutting to size afterwards.
The idea of using a seed emulsion is very interesting.
I would very much like to see your ideas, and I hope others will respond.
I have a 16x20 blade and an 11x14 blade. The 11x14 produces fine coatings but I have trouble handling the 16x20 manually. In any event, at 12 ml / sq ft, even a 600 gram run makes a lot of 8x10s. I regularly produce 17 - 20 8x10 sheets from 200 g of emulsion.
I've found many sources for peristaltic pumps and for syringes. Some are usable and some are not. It would be a rather lengthy discussion to explain all of the details.
Just to mention one... Line fill or line residue is one problem. You have to totally flush the line, but you cannot dilute the solution. There are several solutions, but that is one. The second is the cost.
I can handle it manually, but doing it automatically is a problem.
Thanks for the answer.
I'm interested, as you may have guessed from the other thread
I've had a look at a couple of scientific suppliers here in the UK, but I can't see double syringes.
The best option may be 2 syringes clamped together.
Either that or talk nicely to one of the epoxy manufacturers!
Last edited by ben-s; 04-05-2007 at 03:06 AM. Click to view previous post history.
Lens caps and cable releases can become invisible at will. :D
At work, we use this sort of thing for dispensing UV cure encapsulant:
It is an air propelled dispenser.
We also use the twin syringes for epoxy mixing but these are suplied loaded with epoxy. I will investigate to see if empty double plunger syringes are available.
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I obtained a double syringe plus a pistol grip for appying measured amounts for a work project several years ago. My boss had a good friend who was a dentist and the dentist "loaned" us the pistol grip part and a few new syringes. They were orginally intended for mold making.
Originally Posted by Photo Engineer
I am no longer in contact with this person nor do I have the equipment but it might be worth asking your dentist if they have ever seen such a thing or can show you one of their industry insider magazines or catalogs.
On a related note, there are small, table-top pneumatic systems intended for dispensing "liquids". Kahnetics comes to mind. However my only experience with these was to apply dots of solder paste, not a continuous flow.
Ok, I may as well give an idea of at least two of the problems with double jet syringe addition.
If the plungers are not linked together, then they are no better than having a pair of separate syringes, as they can 'chatter' independantly.
And, if they are machine driven, how do you empty them completely? There will always be a small amount of solution left in them. It is possible to eliminate the residue by either one of 2 methods both of which become more difficult with automation. (BTDT)
You can put a head of air over the solution equal to the volume of the delivery line (difficult to do as you don't want air in the emulsion itself) or you can suck emulsion backwards into the syringe with reverse action on the plunger (difficult if the plungers are automated or separate). (also BTDT) This head of air often will not work with geared or peristaltic pumps as they stop when dry, so other methods have to be developed.
At Kodak, it was simple for me to specify syringe use for a solution as I just wrote Ag/s in the formula or X/s and I never had a worry because anything I wanted was at hand. That little /s changed the delivery system for me without otherwise lifting a finger except to type it in on the keyboard. Now I'm limited by budget, space and time and I assume you are too.
I hope we can mutually solve the problem. Now you are showing me that there is interest so I'm getting myself focused on this a bit (as opposed to doing things for my regular workshop)
I've posted 2 formulas on APUG already and there is a Kodak formula that was posted here by someone else.
possible alternative to ingredient delivery
This would have to be wrestled with a bit, but would something that would deliver ingredients into the mixing vessel much like a fuel injector *but smaller* (metered jet stream, quick opening and closing) be more like what is needed? Yes, it would necessitate a source of pressure, and some sort of control, but that would tie in to the automation aspect.
Or am I totally clueless?
This just occurred to me, and could be the result of too much caffeine, so your patience is requested.
That would work. Of course, as you say, it would have to be wrestled with a bit.