Filament desiccation

[jsc]

I store my unused filament in a pet food container with an O-ring seal and 750 g of silica desiccant (http://www.amazon.com/gp/product/B003QZ ... UTF8&psc=1). I was curious as to what the relative humidity was like in there, so I put together a wireless data logger and threw it in there:

plot.png (7.85 KiB) Viewed 7389 times

It appears to equilibriate around 24% RH. You can see the slight inverse relationship between temperature and equilibrium humidity in the graph, the two times I opened the container, and the time my recording process died for some reason.

I've seen Ed Nisley's desiccant experiments on his blog, and his equilibrium humidity ranges much lower than mine, down to below 15%, the limit of his data logger. I'm wondering if I should add more desiccant.

[ednisley]

add more desiccant.

From the looks of the graph, the desiccant has no trouble keeping up with incoming water vapor, so adding more won't reduce the humidity. More desiccant = longer time to reach capacity, although whether that matters depends on the leak rate: if you get three months from one can, why bother? [grin]

Because the accuracy of humidity sensors runs around ±3% RH and I don't trust their absolute calibration very much, the difference between 15% RH and 25% RH may not be as large as it seems. Both of them look much better than the Basement Laboratory's 55% RH or the steamy outdoors!

That tidy metal-mesh can wipes the floor with my DIY landscaping cloth bags ...

[Lateralg]

What happens to the filament, and the print, when it's used to make a 4-hour print in 55%RH environment?

[jsc]

It takes longer than that for it to affect the filament much. And to be honest, I normally just leave whatever's on the printer on the printer indefinitely. Yes, it drools, but unless I'm trying a dual extrusion print, once it gets going that makes very little difference.