One of the subjects 3D printing channels often talk about is drying filaments for better results. The theory is that some filaments, particularly more hygroscopic (water-attracting) ones, benefit from or need treatment to dry them out and prevent them picking up moisture. Since I mainly print with PLA, which isn’t regarded as overly susceptible to this problem, it isn’t an area I’ve felt I’ve needed to pay much attention to. However, I’ve recently had my PETG out (still on the original roll I bought at the start of 2025) and I noticed I was getting a lot more stringing than I remembered. Messing around with the setting and following suggestions about things like changing the retraction length didn’t seem to make much difference and so I decided it was time to look into filament drying.

You can buy a variety of filament dryers but the cheaper ones are still expensive and the expensive ones can run to £80 or more. I did some research last night but decided not to press the button on any of them. Instead, I’ve experimented today with the DIY option that is sometimes offered. You take an old filament box, cut one side off and punch holes in the other. You then set the heat bed to a suitable level, using the fact that the printers typically now have printing beds with precise temperature control. Pop on a spool of filament, cover it with the box, and leave for several hours.

I used 60°C and left the spool on the bed for about 4 hours. I’ve printed off a small test piece and drying the filament does seem to have done the trick. I’ll probably be printing off some more of the plant supports I was doing earlier this week and that will be the real test as that was where I was being left with a lot of cleaning up to do after the print. However, unless I post a follow-up in a few days, you can probably assume that the DIY option is a worthwhile one to consider in the average UK setting, which isn’t bone dry but certainly isn’t as humid as many places.