Relative Humidity Readings in Dryers
Statements like
- “I dried my filament until the hygrometer said 15%RH”
- “My AMS says it’s 15% inside, so my filament is dry”
don’t make sense.
The hygrometer does not measure the moisture content of the filament1.
It measures the relative humidity of the air in the dryer.
It’s most useful for telling you when to change your desiccant.
-
There are methods to do this, but they don’t apply while you’re drying, require a ton of work ahead of time for each filament you have, and they don’t work if you have desiccant in a container with your filament. ↩︎