Hey Guys,

we do have a non-warping PA as well. I prints with 70 mm/s and even faster without any warpage at all, even large objects with long straight printing paths. We are working on a material with ambient processing temperatures.
We do recommend a heated bed but a closed printer is not necessary.
As much as I know, it is only possible to retard the water uptake but you cannot prevent it completely. Usually by adding water Repellents, the layer adhesion ist influenced negatively.

If color is not an issue, the PA can also be made in a way so it only absorbs water a little bit.

We mail our PA in ziploc bags so you can put them back in the bag and keep it seem.