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  1. #11
    Photo Engineer's Avatar
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    Using SS beakers with temp control hot plates is not advised by most manufacturers. IDK the full reasons for the problems, but I do note ultra rapid heating of the base wrt the top of the solution/beaker and I notice that radiation from the top causes a severe temperature gradiant from top to bottom.

    Actually, I wish I could use a Kodak mixer, but I think that they would shoot me if I tried to get one out of the plant. That beats them all, and there is nothing like a steam CTB for temperature control with a cold water sparger on the cold side. Makes me homesick thinking about it.

    PE

  2. #12
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    Must admit thats news to me. I've used stirrer hotplates with stainless steel beakers , and a temperature probe which sits in the mix in a commercial development lab for toiletries making hot mix emulsions. Nothing in the manual about that.
    The hotplates get hammered daily 5 days a week, Minimum 8 batches of up to 5kg each a day, and the only failures we've had are due to operator stupidity.
    The most common failures are: Burning through the probe cable by letting it drape over the hotplate, and using a prop stirrer and catching the probe around the shaft and corkscrewing it!
    These are the direct heated metal topped ones mind, not the rinky-dink halogen ones, and they're not designed for single degree accuracy, just enough control to get an oil phase up to 70 celsius, and hold it there without the temperature shooting above 100 and filling the lab with smoke
    You're obviously using high quality scientific ones instead, designed for exact control, and good stability

    I agree about the steam bath about being controllable, but they're too slow in heating for my work.

    Interesting to compare how another industry works
    "Flatter Me, and I May Not Believe You. Criticize Me, and I May Not like You. Ignore Me, and I May Not Forgive You. Encourage Me, and I Will Not Forget You."

  3. #13
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    I have 2 Corning mixer hot plates with controllers. Both have in the instructions a warning not to use SS for the container. I have tested them and they work, but the heat gradient is much larger than with glass.

    PE

  4. #14

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    Perhaps it's the stainless dampens the magnetic field somewhat and reduces the stirring capacity. My Corning plate seems to wirk fine with stainless beakers, but I've heard people say not to use them.

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