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  1. #1
    ced
    ced is offline

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    Gum Arabic Preservation

    Gum Arabic Preservation
    Hello any experts! I posted this on DPUG without response maybe my luck is better here.
    I would like to make my own gum arabic of which I bought 300gr. of powder like crystals ( thought they would give me chunky stuff but evidently this is the way it is sold now).
    On scanning many pages on various websites I understand that the mixture needs to have a preservative/fungicide added.
    I have essential oil "Tea Tree" and would like to know how many drops to add (diluted in alcohol). Listerine is also available but not the old type.
    My crystals I understand 300gr to 1 litre of water is this okay?
    Any light on the matter will be much appreciated and sorry if this has previously been discussed. Thanks!

  2. #2

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    Don't add any essential oil preservatives to something you'll be using photographically. Using EOs as preservatives is all well and good for things with a food or cosmetic destination, but not here. Sodium benzoate is probably the least-troublesome compound to add (I'm assuming you're doing gum-bichromate?), and I can't think of a reason ascorbic acid would cause issues either. Still, stick with something unreactive and stable like sodium benzoate.

  3. #3

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    Ah! I see I was right! (Always good to find that out . . . *pats self on back*)

    http://www.apug.org/forums/forum42/4...-solution.html

    1% by dry gum weight of sodium benzoate has been used with success.

  4. #4
    Mainecoonmaniac's Avatar
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    There's also thymol which is an extract of thyme. Smells like Listerine.
    "Photography, like surfing, is an infinite process, a constantly evolving exploration of life."
    Aaron Chang

  5. #5

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    Disclaimer: not an expert. I have made gum arabic from the the spray dried powder--you do indeed need a preservative or like any food based product the gum will rot quickly. Two options I looked into are thymol and sodium benzoate.

    Thymol is used in antiseptics. It will not dissolve in water, but must be used in alcohol. My notes say to use 10 grams in 10ml of alcohol. I'm sorry to say I haven't used thymol personally so I don't know if that's isopropyl alcohol from drugstores, or grain alcohol like everclear; nor do I know how much gum solution this goes into.

    Sodium benzoate is a food preservative and you can find it on the label of soft drinks. It readily dissolves in water. I use this in my gum solutions and it works well. You can get it from the Photographer's Formulary. I use 0.5 grams for every 100 grams of dry gum arabic powder. The standard ratio for making gum arabic is one part gum powder to two parts water.

    For what it's worth, the stuff I make from scratch looks (same dark tan color) and acts exactly like the premade gum arabic solution sold from Bostick and Sullivan. It's definitely fun to make your own, but in terms of cost and convenience--making it versus buying a premade bottle of gum--my opinion is that one isn't any better than the other. Good luck!

  6. #6

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    Traditional Listerine is thymol. Just read the label first. And in that form it can be diluted with water.
    Doesn't take much to get the job done.

  7. #7
    ced
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    Thanks to all!! In my opinion "Experts", if you realise where I am starting from complete novice regards gum bichromate.

  8. #8
    Hexavalent's Avatar
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    I use thymol - bought from a compounding pharmacy for a couple dollars.

    "Dequadin Oral Paint" (found in the dental section of pharmacies) also works well - just a drop or two per litre of gum has kept a jar of gum fresh for a year at room temperature.
    - Ian



 

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