There seems to be a lot of “tribal truth” about material swelling due to humidity, which reputably causes issues cutting cleanly on the GF. I don’t believe this to be the case.
For reference, I posted this thread back in June, where I presented evidence that it’s not an issue. This thread provides further data. Note that I live in Atlanta, GA, USA. Humidity here in the summer is brutal. Plus we’ve had record rainfall in the past few months.
If my samples didn’t “swell” after 4 months exposed to GA humidity, yours aren’t going to indoors.
Right after that thread (June 1), I printed four sets of sample “chips” from Baltic Birch, Proofgrade Maple Ply and Draftboard, and placed them in different locations. One set was left on my GF (adjacent to my material storage shelf), one went in the car port, one on a window ledge on my deck exposed to all elements, and another was vacuum sealed and left alongside the set on the machine in my workshop.
Here are the before and after measurements. The only one that “swelled” was PG Maple Ply, and that was by <1/100". EDIT - the draftboard left outside also swelled a little.
The sample chips (note how bleached the DB was after 4 months in the sun):