PAHT-CF hygroscopic question

[delta1seven]

First time printing Nylon lately.

I dried PAHT-CF in my dryer for about 16 hours. I then put it in my AMS, and it printed great.

I left the PAHT-CF in my AMS for about a week. My ams stays at 10% humidity and is stored in my home office. But when I went to go print with the same PAHT-CF again today (without ever removing it from my AMS) it appeared to be wet as when it printed it has a fuzzy texture on the walls of my print.

Is this normal? I know nylon is supra hydroscopic, but I would have assumed with it being in my sealed AMS that it wouldn’t have absorbed any humidity in just a week.

Side question: Any help on printing PAHT-CF on the Textured PEI Plate? I tried the aqua-net hairspray and my print didn’t seem to really stick to my build plate too well.

[RocketSled]

PAHT-CF (PETG, PCTG, hypdroscopic filaments) acceptable humidity

In my experience, no, the AMS has a long, sloooow humidity time constant but filament print quality still degrades after some time in the AMS, requiring the filament to be re-dried. But that’s the “stock” AMS. There are plenty of project files to print that allow you to significantly increase the amount of desiccant that can be loaded inside, and those tweaks might address the stock configuration’s slightly-less-than-ideal performance.

[djeZo888]

Yes, this is normal. I kept my PAHT-CF in drybox with bunch of silicagel. After 2 weeks, filament is wet and useless - needs redrying. Basically, you have to print it out of drybox or AMS and redry every second day or even once per day. Like some people say, best is to run the filament directly out of dryer, because if you have long print, your filament may get wet by the time your printer is finished.

There is massive difference in quality. Fully dried PAHT-CF looks like PETG-CF. Just slightly wet looks more like PET-CF with very rough surface.