Drying time - PLA

How long should you dry a brand-new unopened roll of PLA?

Would you keep it in the dryer while printing a 13 hour print?


Most times I don’t dry out of the box filament, unless I think there is an issue.
When I do use a dryer, I dry for a least 6 hours.
95% of the time, I will print straight from the dryer, I’ve done 72 hours print like this.
I always print ASA, TPU & PETG from a dryer…PLA if it’s a overnight or longer print.

Thanks for your thoughts!

PLA is not very hydrophilic. Amongst all the filament types, it’s about the best. The problem with PLA and humidity is more that it makes the filament brittle and prone to breakage as it passes through the printer’s filament path. If it still feels good and flexible, that’s a good indication you don’t need to dry it. If it snaps like uncooked spaghetti, it definitely needs drying.

There is no one answer to “how long”. I put my rolls in the dryer the day before I expect to print, so they get a minimum of 12 hours and usually closer to 24. Filament can’t be “over dried” so it’s no big deal to go longer, it’s added insurance.


Thanks… I plan on using a brand new roll of Voxel PLA+ for a 13 hour print. My plan is to dry it today for about 6 hours, then keep it in the dryer while I am printing.

Thank again for all your ideas.

Best… Richard

My method of controlling filament moisture is based on weight, detailed here. I’ve now have an Eibos dryer, but the only time I print directly from the dryer is with TPU and PC, or maybe PETG if I expect to be using the same spool over several days.

I tend to be a bit obsessive about printing with dry filament, but PLA is slow to absorb moisture and the material I worry about the least. Though I’m in a humid climate, I can leave PLA out for at least a week or so (no AMS) without moisture problems. (In that case, I do dry it again before storage.). I don’t worry about one or two grams of moisture weight gain, six grams or more definitely calls for dryer time.

You’ll get the vast majority out of PLA fairly fast, 3-4 hours at ~45-50c with airflow will take probably 90% of absorbed moisture out

I do now have hyrgrometers but I do not know what defines dry. What is a good number? At what point are problems going to occur?