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  1. #1

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    Mixing Pextral's Two Bath; Substitute for Sodium Hydroxide?

    Hi!

    I plan to mix up a batch of Pextral's Two Bath developer as detailed in the recipes section.

    The recipe calls for sodium hydroxide in the second bath (1% solution), presumably as an accelerator. The job is done in "seconds", so I'm guessing that a lesser base would still be effective.

    For reasons of health and safety, would there be any substituting NaOH for say potassium carbonate or sodium carbonate? What ratios should I use?

    Thanks!

    Justin

  2. #2

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    TSP, trisodium phosphate will likely make a good
    substitute. A ph only a little short of lye. Dan

  3. #3
    Ole
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    Carbonates could be worth trying, too. It's not the concentration that's important, it's more the pH. Using a lower pH second bath will change the characteristics, but could well give good results.
    -- Ole Tjugen, Luddite Elitist
    Norway

  4. #4

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    Thanks Dan, and Ole. I will see if I can find TSP at the hardware store, but in the meantime, I'll mix up some sodium carbonate and see if that works well enough.

  5. #5

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    pH of 1% sodium hydroxide is 12.7:
    http:http://www.pacia.org.au/_uploaditems..._hydroxide.pdf
    pH of 10% sodium carbonate is 11.7:
    http://www.intox.org/databank/docume...carb/cie20.htm

  6. #6

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    Alan, that's a godsend. A 10% solution should be a good starting point then. Thanks!

  7. #7
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    Slaked lime from the garden shop + sodium carbonate from the swimming pool shop + water from the sky makes a solution of sodium hydroxide with precipitated calcium carbonate. It is left as an excercise for the student to calculate the amounts of lime, soda ash and water to make a 1% solution in sufficient quantity that you can get the amount of 1% solution you want by siphoning it off, leaving the precipitated limestone. It won't hurt, of course, if you make more than you need.
    Gadget Gainer

  8. #8
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    1 molecular weight of calcium hydroxide + 1 molecular weight of sodium carbonate produce 2 molecular weights of sodium hydroxide and 1 molecular weight of calcium carbonate. 1 molecular weight of sodium hydroxide is 40 grams. 40 grams in 400 ml of solution is a 10% solution.
    Gadget Gainer

  9. #9

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    sodium hydroxide susitute????

    "ultra bleach" on the shelf in the supermarket lists active ingrediants:
    sodium hypochlorite, sodium hydroxide

    what do you think????

    hey gainer-can't find my way back to site where your aticles on vit c dev most especially using anti freeze to make non oxidising shelf solutions

    can't use pdfs so i need to read on site-can you direct me?

    thanx

    vaya con dios

  10. #10

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    just remembered-store brand cheapo "ultra bleach" only active ingrediant: sodium hydroxide-it is close to 1% i think

    why mix when you can buy off the shelf???

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