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Thread: Pyro-Uno

  1. #11
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    I wll give this a go on the weekend. I always expose 2 sheets for backup and development options and right now I have about 100 second sheets at my disposal.. Should be fun..Evan Clarke

  2. #12

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    Quote Originally Posted by gainer View Post
    So, if you succed, all we will have to decide is whether we want the cat or the gal.
    That is one way of putting it. At this point in my life a new cat would be a lot less expensive than a new gal.

    But a one-solution developer makes a lot of sense for some people. You would be surprised how many people are simply unable to get it right when mixing two part developers like PMK and Pyrocat-HD. Folks have found more ways to screw up than I ever might have imagined!!

    Sandy

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    I think some of it is the routine you're used to. When I decided I wanted to try a pyro developer I was using HC110 mixed straight from the bottle. To be honest, that's about the only reason I chose 510 Pyro over any of the two solution pyro developers. Seems like at the time it was the only one solution pyro I had heard of.

    Not a very good reason for selection of one developer over the other, but at the time it seemed worthwhile. I suspect there are others that will try this mixture based on the one bottle.

    Mike
    Last edited by mikebarger; 07-30-2009 at 06:23 PM. Click to view previous post history.

  4. #14
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    Well, with two parts plus water, there are at least 3 things to screw up, and 3 factorial (6)possible outcomes only one of which is the desired one.

    With regard to high viscosity, I have found that the Chemistry Store, which is about the cheapest place to get a gallon of TEA, also sells containers including Boston rounds of various sizes and lotion pumps to fit. The lotion pump is the best way I have found to move small quantities of gooey stuff from the container to a graduated cylinder. Each stroke of the pump moves about 1/2 ml. You don't have to use the full stroke. I see they are out of stock in white pumps but have others. Another place to look is www.sks-bottle.com.
    Gadget Gainer

  5. #15
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    TEA is hygroscopic. The weight gain at equilibrium is 20% at 50% humidity, 25% at 60% humidity . Perhaps that is another way a lotion pump can help. It would minimize contact with air while decanting from storage. If the TEA solution is heated to 250F not long before storage, it ought not have much water in it initially.

    50% humidity is not uncommon in these parts.
    Gadget Gainer

  6. #16

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    Quote Originally Posted by gainer View Post
    TEA is hygroscopic. The weight gain at equilibrium is 20% at 50% humidity, 25% at 60% humidity . Perhaps that is another way a lotion pump can help. It would minimize contact with air while decanting from storage. If the TEA solution is heated to 250F not long before storage, it ought not have much water in it initially.

    50% humidity is not uncommon in these parts.
    50% humidity is actually fairly low. I know that APUG members live in all sorts of climatic extremes, but in a temperate climate the outside humidity is often 60% to 90%. When you have the heating on the relative humidity inside becomes less, even though the absolute humidity is unchanged. I wonder if it's the relative humidity or the absolut humidity that is relevant in the case of TEA based developer absorbing water from the air, a little bit every tme the bottle is opened.

    For this reason and because of possible oxidation I generally don't use the last bit of developer in the bottle, if it's a highly concentrated type which takes many openings of the bottle to use up.

  7. #17

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    When I mix the 510 pyro I put it in small enough bottles that I can use it up fairly quickly (months). When I get down to the end of the bottle I turn it upside down over the next bottle for a couple hours after making the first batch from the new bottle. What little is left I don't worry about.

    Sandy's brew could be handled the same way.

    I don't think I'd want to be using a TEA developer out of a two liter bottle.

    Was the pump strokes pretty consistent in the amount they delivered with each stroke? If you're getting .5ml per stroke and need 10ml, would the 20 strokes introduce to much variability batch to batch?

    Mike

  8. #18
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    I'm attaching the figure from the Dow specs.
    Attached Thumbnails Attached Thumbnails hygroscopicity.jpg  
    Gadget Gainer

  9. #19
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    Quote Originally Posted by mikebarger View Post


    I don't think I'd want to be using a TEA developer out of a two liter bottle.

    Was the pump strokes pretty consistent in the amount they delivered with each stroke? If you're getting .5ml per stroke and need 10ml, would the 20 strokes introduce to much variability batch to batch?

    Mike
    Bottles with the lotion pump are available in a wide range of sizes. I'm 82 years old. I wouldn't think of mixing 2 liters for my use.

    I wouldn't depend on the lotion pump for accurate measurements. I would use it to transfer from storage to a graduated cylinder. Without the pump, this is a problem. Of course, the oral dosing syringe that looks like a hypo is an alternative, but it is a bit clumsy at times. I tried using the cylinder from such a syringe, without the plunger, as a graduated cylinder. The tip must be covered and when the desired amount is in the cylinder, the tip is to be placed over the receiving vessel, the tip is opened and the plunger is reinserted to insure getting all the stuff from the cylinder walls. The obvious tip cover at the time was a fingertip, which is a bit messy and in some cases dangerous. Since the concentrate is going into water in this case, it is better to rinse the measuring cylinder with some of the contents of the receiving vessel.
    Gadget Gainer

  10. #20
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    TEA has another property that may be confusing. It freezes at 21.6 C, but is easily supercooled, which is the way most of us see it most of the time. I have received a jug of it that had lumps of "ice" in it. I'm sure many darkrooms are below that temperature at times.
    Gadget Gainer

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