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Desiccant dehydrator

A project log for Solar filament drier

How to keep filament dry while being too poor to afford electricity.

lion mclionheadlion mclionhead 09/06/2022 at 19:180 Comments

Sponge tire, despite months of drying out the filament in the solar drier & then a few weeks with a dry tote.


Eventually a calcium chloride pack with filament that was previously in the solar drier became rock solid.  The way to know if calcium chloride is hydrated is if it's hard.  It showed the desiccant was pulling more water out than the solar drier.  So the solar drier might be good enough to get minimal printing in a few days, but the best results are going to come from a desiccant.

Lions succumbed to making desiccant packs out of paper towels & ordinary calcium chloride, then storing filament with those.  The trick is the amerikan people only allow 6"x11" paper towels  to be sold, which limits the desiccant pack to a long narrow tube.  Calcium chloride in the long term may cost more than new filament.

Dry tote was a fail.  A roll of TPU with that produced the shown tire.  Calcium chloride has proven to be filament crack.  It's most affordable for renters as DampRid in 2 pound bags.

After many months of various filament drying techniques, the best solar drier has proven to be a sack of calcium chloride in a container with a fan, heated in sunlight.  Maybe it can have a solar panel to know when to turn the fan on & a sensor to detect when the calcium chloride is expired.  Powering it with solar would require too much space.  All the air pumps, the triac, the tubing would go to landfill.

As always, it's not so simple.  Making the container air tight requires some kind of expansion area.  There is a long tube, but osmotic pressure will force water in.  A ziploc bag wouldn't have enough air to circulate.

From an electronical standpoint, there is a desire to have it automatically detect from dewpoints when the desiccant has expired.  It could be an online graph that an animal interprets, but an LED for expired desiccant would be better.

Definite improvement, though this filament continues to be wet on the inside from the factory.  Completely unrolling it may be the next step.

The data showed it hitting lower humidity in the dark but equivalent humidity in the sun.  Since most of the time is spent in the dark, it overall takes more water out.  The circulator fan should run all night.  The desiccant seems to saturate by day 3.

Burning money to remove water should always be more effective than pumping air.  The mane problem is how much water the desiccant releases back into the filament when it gets hot, how much it's going to cost to manetain an advantage over pumping air.  Given the challenge of drying filament, it might be justified to finally use a peltier condenser or mechanically unwind the filament in the drier.

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