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  1. #11
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    That was the same thing that happend to they guy in the thread. Knowing that before hand, you can always do the oven fix. probably too late for you.

  2. #12

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    I think my TEA came from the same place. The PC-TEA I made worked but the developing times were longer than I expected. After the PC-TEA mixture cools it turns from a pale tan to a dark green/brown over time but still works fine.

  3. #13
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    I just went over to their site, and there is no mention of it's purity. The MSDS sheet clearly states it though. You would think something like that would be on the product page.....

  4. #14

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    Checked with The Chemistry Store site and their TEA is said to be 99% pure. The price is also very reasonable. It is the TEA that I use. BTW, the same caveat also applies to the glycol that you use. This is why I don't recommend using antifreeze which can contain water.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #15

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    Quote Originally Posted by Gerald C Koch View Post
    Checked with The Chemistry Store site and their TEA is said to be 99% pure.
    I did an experiment: I weighed 10 ml of my TEA five times, and the average g/ml was 1.108.
    The specific gravity of TEA is 1.126, and an 85-15 mixture of water works out to a g/ml of 1.107.
    That's very close. I think that confirms that PhotoFormulary's TEA contains about 15% water.

    I'm sure the manufacturer added water to boost profit. I hope they used distilled water and not tap water or recycled sewage.

    PhotoFormulary will be hearing from me in a day or two, encouraging them to use 99%. That 85% stuff is not suitable for developers.
    BTW, I checked their propylene glycol: It's 100%, so at least that's the good stuff.

    Mark Overton

  6. #16

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    Mark if you did click on Photograpers Formulary's MSDs for their TEA, you would see that they state it is definitely 85%........

    Just click on the link and scroll down a little, it is a scan of a typed letter obviously copied over and over so it i nearly illegible, but is says 85%.
    I think you will be told off if you contact them. Check before you buy!

  7. #17
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    Don't forget that TEA can be a mixture of TEA, DEA and MEA, and this will change the properties slightly in terms of silver halide solvent capability, pH and sg. And, sg is sensitive to temperature. You have to know the temperature of the reference reported in the literature and use that for your test.

    TEA is hygroscopic, which means that it absorbs water from the atmosphere rapidly. It is often difficult to prevent TEA from becoming more dilute with time.

    I use Formulary TEA at home here with no problem and I won't get a kickback from them for this comment. I am neutral in this, and merely pointing out the facts regarding TEA.

    And, BTW, the melting point is a key item in determining the purity of any organic compound. For TEA it is 20.5 deg C. So, in the average room at 68 deg F or 20 deg C, TEA should be slush. If it is impure, at that temperature, it would be liquid. It appears as a pale yellow slush. My room is 68 deg F and my TEA is a pale yellow rock! I have to warm it to get it out.

    PE

  8. #18
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    Quote Originally Posted by Photo Engineer View Post
    Don't forget that TEA can be a mixture of TEA, DEA and MEA, and this will change the properties slightly in terms of silver halide solvent capability, pH and sg. And, sg is sensitive to temperature. You have to know the temperature of the reference reported in the literature and use that for your test.

    TEA is hygroscopic, which means that it absorbs water from the atmosphere rapidly. It is often difficult to prevent TEA from becoming more dilute with time.

    ...
    PE
    The MSDS at PF lists TEA >= 85 % <= 89% with the balance being DEA (not water). Of course, once the lid is off the jar, water practically jumps in.
    - Ian

  9. #19

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    I would not recommend the PF's TEA because of the amount 11% to 15% DEA in it. DEA being more basic than TEA will throw off the pH of any developers made using it. What PF is selling is designated as technical grade TEA.

    Here are approximate pH values for a series of 4% solutions; TEA 99% 10.1, TEA technical grade 10.4, DEA 11.4, MEA 11.9
    Last edited by Gerald C Koch; 01-30-2012 at 12:44 AM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  10. #20

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    Quote Originally Posted by Gerald C Koch View Post
    I would not recommend the PF's TEA because of the amount 11% to 15% DEA in it. DEA being more basic than TEA will throw off the pH of any developers made using it. What PF is selling is designated as technical grade TEA.
    Here are approximate pH values for a series of 4% solutions; TEA 99% 10.1, TEA technical grade 10.4, DEA 11.4, MEA 11.9
    I just mixed a 4% solution of my TEA and got (at 20C) a pH = 10.85.
    That was hard to believe, so I checked the pH of my 10.01 buffer solution (at 20C), and got pH = 10.04.

    Also, the temperature of my TEA this morning was 17.5C, and it was viscous but pourable liquid. I had no trouble swishing the thermometer-probe around in it.

    The specific gravity of DEA is 1.090 versus 1.126 for TEA. My TEA's sg is 1.108.

    All the above measurements are telling me that my TEA has far more than 15% DEA in it. The sg says it's 50% DEA.
    That would also explain why my Instant Mytol was much "hotter" than expected: It had a pH approaching 9.0 instead of the expected 8.2.

    Mark Overton

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