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Drying Fliament Outside in Summer  

Eminent Member
Drying Fliament Outside in Summer

Here in Southern Australia we have hot dry summers, with temps regularly over 100 degrees F and low humidity.     On such  day, would it be acceptable to put my filament outside and in the shade to ensure that it's properly dried.

I normally keep it in it's orginal packaging, but with an added silica gel filled cylinder that fits into the spool hub.

Posted : 26/09/2021 1:21 am
Illustrious Member
Good for storage and preventing problems, maybe not for drying

Recommended drying temps for PLA start at around 55C/131F, so that might not be ideal for drying filament that has absorbed moisture. You also want to keep it below 70C/158F where lower temp filaments start to soften (glass transition temp). I'd recommend a solution with a bit more control.

The good news is that during those hot months, you're unlikely to have the problem. It's when you get higher humidity with lower temps that you'll more likely need a solution.

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Posted : 26/09/2021 1:38 am
Honorable Member
Posted by: @stinkypete

Here in Southern Australia we have hot dry summers, with temps regularly over 100 degrees F and low humidity....

I'm not a physicist, but... It's not that much about temperatures, as is about filament surrounding humidity. That is, if surrounding humidity is 35%, then that's the lowest what filament can get. Regardless of for how long it will be exposed in this environment -even if temperature is 120F (49C).
Is similar with (filament) dryer, where we heat air inside to force water evaporating from filament. In that case there must be hole(s) on dryer where moisture can escape out. Otherwise total amount of humidity inside dryer won't change -evaporated water will just collect as steam on coldest part inside dryer (for that reason we put silica gel together with filament inside dryer). Of course, filament will lose humidity even if steam collects somewhere inside dryer. However, as soon dryer stops drying (heating) we need to take filament out -otherwise filament will absorb water back (unless water is bound in silica gel). Is a slow process, so no need to gaze at dryer for waiting for it to stop.
When we say "recommended drying temperature", that doesn't mean that such temperature is needed for to dry filament. Filament will dry even at 105F (40C), however it will take much longer than at 131F (55C). And because we wish to dry as fast as possible, we choose the highest possible temperature for particular filament. As for PLA, I prefer using a bit lower temperature (45-50C) and dry 1-2 hours longer.

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Posted : 26/09/2021 8:09 am