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Thread: Chemistry 101

  1. #41
    Rudeofus's Avatar
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    Quote Originally Posted by Roger Cole View Post
    Quote Originally Posted by Gerald C Koch View Post
    I don't think that saying people should be careful and always know what they are doing is in any way "alarmist."
    And why, for the ten thousandth time, is APUG the only vBulletin site I use that doesn't allow multiquoting? Argh.
    Works for me ....
    Trying to be the best of whatever I am, even if what I am is no good.

  2. #42

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    Surely it's far better to be informed and thus more responsible for your own safety – not to mention those around you who may unwittingly stumble across your chemicals?

    ~S

  3. #43
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    Quote Originally Posted by Rudeofus View Post
    Works for me ....
    How do you do it??

    I can of course copy and paste and add the relevant code myself, but that's a huge PITA and I can't be bothered to do it. All the other vBulletin sites have a button for multi-quote and I can click it beside each post I want to quote and then, when I reply to the last one or hit the reply button at the bottom, all of them are quoted in my text. I can't find such a button here.

  4. #44
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    Quote Originally Posted by Rudeofus View Post
    Works for me ....
    And besides, your quote showed one inside the other, not sequentially, like this (done by copy and paste) of my own post:

    Quote Originally Posted by Roger Cole View Post
    How do you do it??

    I can of course copy and paste and add the relevant code myself, but that's a huge PITA and I can't be bothered to do it. All the other vBulletin sites have a button for multi-quote and I can click it beside each post I want to quote and then, when I reply to the last one or hit the reply button at the bottom, all of them are quoted in my text. I can't find such a button here.

  5. #45

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    Quote Originally Posted by Photo Engineer View Post
    I think that due to some recent posts and threads here on APUG, it became obvious that people are doing a lot of "experimenting" who have no knowledge of chemistry at all and Jerry has jumped in to help save them from possible grief.

    I myself, have tried to prevent accidents when people were advised to heat chemicals in cook pots on the stove and etc..... Or, even heating chemicals in the microwave. All of these are dangerous practices that should not be done, especially for the average unprepared person. After years in the lab and seeing many accidents happen even to trained professionals, I advise caution of you are going into the "unknown" and ask the experts for advice.

    PE
    PE

    you are funny ... "possible grief"

    its like someone brewing their own silver nitrate in their kitchen
    because someone on a web forum said it was easy to do ... oh yeah,
    by grief you mean "accidental death" ...

    to quote: mr j. frank parnell:
    Radiation, yes indeed! You hear the most outrageous lies about it. Half-baked goggle-boxed do-gooders telling everybody it's bad for you. Pernicious nonsense! Everybody could stand a hundred chest X-rays a year. They ought to have 'em too. When they canceled the project it almost did me in. One day my mind was literally a-burst. The next day nothing. Swept away... But I'll show them. I had a lobotomy in the end.
    i hope no one looks in the trunk !
    Last edited by jnanian; 09-30-2011 at 07:28 AM. Click to view previous post history.

  6. #46
    Photo Engineer's Avatar
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    There are several emulsion formulas floating around on the internet that were compiled by amateurs who know no chemistry. These in particular refer to making an acidified emulsion which uses citric acid during the make, and then which calls for ethyl alcohol to reduce bubbles or to aid in coating the emulsion. Well, this combination of Silver Nitrate, Citric Acid and either Methyl or Ethyl Alcohol is a route to disaster. Under the right conditions, it can form an explosive mixture! That is why I do not use acid in unwashed emulsions and why I use i-Propyl Alcohol.

    Now, how many knew that one? Of course I am not aware of any explosions by this route, but then why take the chance. OTOH, maybe we have not heard from people who have had explosions from this reaction as they cannot report their experience to us!

    PE

  7. #47

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    Quote Originally Posted by Photo Engineer View Post
    There are several emulsion formulas floating around on the internet that were compiled by amateurs who know no chemistry. These in particular refer to making an acidified emulsion which uses citric acid during the make, and then which calls for ethyl alcohol to reduce bubbles or to aid in coating the emulsion. Well, this combination of Silver Nitrate, Citric Acid and either Methyl or Ethyl Alcohol is a route to disaster. Under the right conditions, it can form an explosive mixture! That is why I do not use acid in unwashed emulsions and why I use i-Propyl Alcohol.

    Now, how many knew that one? Of course I am not aware of any explosions by this route, but then why take the chance. OTOH, maybe we have not heard from people who have had explosions from this reaction as they cannot report their experience to us!

    PE
    I don't usually read the emulsion forum so this is scary information.
    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

  8. #48
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    I advise my students to avoid adding acid to unwashed emulsions and also to ensure that the Nitrate is fully washed out before they heat it up prior to coating. I advise them to use surfactants and not alcohols, although IPA is suitable as is t-Butanol to carry organics and to reduce bubbles. EtOH and MeOH are generally a NO NO.

    PE

  9. #49

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    "Johnny was a chemist, but Johnny is no more; for what he thought was H20 was H2SO4"

  10. #50
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    OK, so there is some good advice here about us non chemist fooling around with mother nature. From a more present situation, I have to say I'm not one to always take good advice. I'm careful about what and how I mix my chemicals for developer and fixer, but, and this is a big one, I have'nt always been good about wearing gloves when working with developers. My first warning that I wasn't exactly bullet proof came when I accidently got some WD2D+ on the fingers of my left hand. I washed them off right away and continued to work. A couple of days later the skin on my fingertips started cracking and peeling off!! That was nine months ago. I now always wear nitrale gloves when woking with developers, but sometimes they get into the glove on one hand or the other and I still have issues with peeling, blistering and painful skin. Sometimes even the fingers I contaminated nine months ago start cracking and bleeding again. And no, I havn't been to a dermatologist yet. I fear that I have finally hit the saturation point with toxins. I'm 64 years old, and have had a lifetime of exposure to hazards of one kind or another. Be careful out there.

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