Home Cosmetic Science Talk Formulating General Eliminating fumes when dissolving lye (NaOH)

  • Eliminating fumes when dissolving lye (NaOH)

    Posted by mikethair on March 18, 2024 at 1:46 am

    Again, for the thousandth time I’ve been asked by a soap maker about the fumes produced when dissolving lye (NaOH). And as a result, they go to extraordinary lengths to avoid the fumes. Even moving the mixing of lye batches outdoors. Now in my eyes this is dangerous.

    But it’s totally unnecessary, guys!!!!

    In fact, with the correct equipment, an understanding of basic chemistry, and the correct technique, the dissolving of lye will not create fumes in your work area.

    And yes, NaOH is very dangerous. So don’t take risks.

    Here are two alternative approaches.

    Method # 1

    Very simply, substitute the weight of water with ice. You should be able to buy 4 or 5 Kg bags of ice cubes. The ice completely counters the heat generated, so you will have zero fumes. Add the NaOH to the ice.

    Method # 2
    (1) Weigh out the required NaOH into a small stainless-steel pot with a lid.

    (2) Weigh out the water required into another stainless-steel pot with a lid.

    (3) Remember, you will add the NaOH to water, not the other way round.

    (4) Add about 1/3 of your NaOH to the water. Stir well. As you stir, the solution will go from clear to cloudy white. This is the stage at which it produces fumes. Place the lid on the pot and wait.

    (5) The length of time to wait depends on the ambient temperature. In our case, it’s around 5 – 10 minutes.

    (6) If you open the lid, you see the solution is clear. And there are no fumes.

    (7) Add the second and third of your weighed NaOH. Mix vigorously, and replace the lid. Wait.

    Again, after about 5-10 minutes, open the lid, and you will see a clear solution. Repeat for the last portion of NaOH.

    It is important to know that fumes only occur initially after adding NaOH when the solution goes from a clear to a cloudy white colour. In a few minutes, the solution turns clear, and there are no fumes.

    <b class=””>If you are thinking of scaling up your soap-making business, I’m available for consultation.

    And, if you have any questions…..feel free to ask.

    Dr Mike Thair

    Skincare Product Development and Manufacturing.

    mikethair replied 1 month ago 1 Member · 0 Replies
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