Yes, its that time of year again, storm after storm with high humidity. If you are like me, you left the printer on the reel thinking you would print soon. A couple weeks later when you are asked to print a robot for a school printer, your prints have holes in the top surface. If you quickly push the PLA through the extruder you can even see small jets of steam. Argh… what to do?
I found an old Rubbermaid container in the garage and placed my reels of PLA into it with a small dehumidifier and digital hydrometer I bought on Amazon. I let it running for a several days checking on the humidity level on a regular basis. Once the humidity was less than 40% I pulled out a reel and started printing. It is like having a brand new reel. I printed the 3DBenchy boat with different reels of PLA. The green one has the holes from the water absorption which is converted to steam once heated.
The easiest way I have found to keep this from happening to keep the PLA sealed in a zip-lock bags with some Silica Gel Desiccants Packets unless you are using it. One method I tried unsuccessfully was putting the PLA into the oven on the lowest setting, Mine is 170F. It may be dry, but it relieved the internal stress and had slight kinks. This condition the PLA would not slide freely in the tubing.