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PolyDryer Humidity: White PETG

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The white PETG filament started out at 39 %RH and 50 g of silica gel dragged it down to 23 %RH after a three days: still unusually high.

The beads weighed 54.6 g, a weight gain of 9 %, which is about as much as they’ll take. I replaced them with 50 g of new-from-the-bottle beads and the meter dropped to 14 %RH overnight.

Running the tiny fan for another day made no difference:

Polydryer Box desiccant tray - fan
Polydryer Box desiccant tray – fan

Thereby confirming my suspicion that air circulation inside the box isn’t nearly as much of a problem as I expected.

So filament need not arrive bone-dry and, with enough surface area exposed to the air, silica gel beads can adsorb their limit of water vapor in a day or two.

Comments

4 responses to “PolyDryer Humidity: White PETG”

  1. John Ferguson Avatar
    John Ferguson

    HI Ed, How hot and how long do you heat the beads to recycle them? FWIW, I’m looking at the $119 heater which mounts atop the BambuLab X1-C and other than providing the same environment for the array of spools it’s loaded with looks like a good deal.

    At the same time, I had a lot more trouble with moisture when the printers lived in the garage rather than our apartment. but then $119 is pretty cheap.

    I bought an Esun drier some years ago for use with the M2, and it did work, but the beads worked better. SWMBO is not enthusiastic about me baking beads in the oven even though we’ve switch over entirely to micro-wave and air-fryer.

    Reply
    1. Ed Avatar
      Ed

      Basically, keep them over 100 °C for a few hours and, if you’re compulsive, stop after they lose a reasonable amount of weight:

      Polydryer Humidity: Another Month of Data

      I do not understand how the heaters work, because the instructions have them running in a closed box with nowhere for the water vapor to go: “regenerating” the beads without venting the vapor outside cannot possible improve the situation.

      Reply
      1. john ferguson Avatar
        john ferguson

        The $119 Sunlu has a manually moved vent cover on top. Our new Ninja Aire frier can generate 200C and I have a bwol for it which we never use. I wonder if it canstand continuous 200C. ??

        Reply
        1. Ed Avatar
          Ed

          There’s only one way to find out: FOR SCIENCE! :grin:

          Reply

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