Filament: How Dry Is Dry Enough???  

RE: Filament: How Dry Is Dry Enough???

I don't have any authoritative cites, but I've been led to believe that relative humidity under 30% is good and low to mid 20s is preferred.

I have two dry boxes with silica gel packs and each with a cheap humidity gauge.  I posted photos in the 'tool' thread last week.  These are just plain old Home Depot storage tubs.  When the humidity creeps up over 30%, I'll bake the dry-packs in the oven for a few hours, as per instructions, and place them back in the dry boxes.

These boxes are very good for filament that is not going to be used for a while.  Not so good for repeated opening and closing over a short period of time, as each opening will cause the humidity to spike.

I have yet to have any issues attributable to wet filament, and I want to be sure that I don't.

RE: Filament: How Dry Is Dry Enough???

30% is good and low to mid 20s is preferred.

So, following the KISS principle, I've made my four storage boxes also be dispenser boxes. Pic shows one of them in action during a print using the gold filament. I printed up the white fittings that snap into a 3/16" hole in the plastic box. They have an angled hole for the filament feed-through. You can see the Eva-Dry and my temp/hum gauge inside the box. The reels just ride on their rims on the slippery plastic box bottom--no axle needed. I can print from any reel in the box, and it's easy to change out the box with another four reels of different color/plastic. I never have to open any of the boxes, so the humidity stays low. The roller on the top of the Prusa frame still needs some work to trap the filament a little better, but it works fine as soon as there's a little tension on the filament. Incidentally, the humidity usually stays at 25%, but I had the box opened to mount the gauge just before the pic. Takes about 20 minutes to come back down to the 20's. I just ordered some bulk silica gel beads (5 Lbs) and a four-pack of smaller temp/hum gauges. I'll make up my own packs that will fit better and give the middle reels better clearance. Temp/hum gauge will be incorporated into those. I'll just oven-recondition those as needed.

RE: Filament: How Dry Is Dry Enough???

Yours is far more elaborate than mine.  I have seven spools of the filaments I most often use on a pipe rack above the printer, and getting that into a box would not fit in the space I have for the printer.  Besides, for things like black PLA and black ABS, I tend to use them up quickly enough than I don't think the ambient humidity has time to spoil them.  For example, I recently changed the black ABS spool on the rack, and I've been using what remains on the old spool for smaller items for a couple of weeks, and it performs just as it did when it was new a couple of months ago.

RE: Filament: How Dry Is Dry Enough???

My printer sits on an IKEA desktop in my office, and I wanted to reduce it's visual impact as much as possible (happy wife; happy life). She cringed at the sight of the printer with two reels of filament flying above on the standard Prusa factory rack. So I wanted my dispenser box to be positioned low and behind the printer, and worked hard to minimize the front-to-back distance. I got it down to just under 29" from the wall to the very tip of the printer control panel.

The pic shows the rig from the side, and you can see the box support is notched to allow the print bed to get to it's rear-most position. The notch is bigger on the side you can't see to allow the bed heater connector to clear the support. I may build a drop-over facade enclosure for the plastic box, again to reduce it's visual ugliness in a home office environment.

You can also see the gold filament feed wheel I designed mounted on the Prusa frame. For the moment, my filament moves "open-air" from the dispenser box to the print head, but I may go to a teflon tube for that if that improves the visual impact.

RE: Filament: How Dry Is Dry Enough??? (Answered, sort of...)

So I now have completed four storage-dispenser boxes holding 16 reels of various types of filament. I bought a 4-pack of Vieanic digital humidity/temp sensors and mounted them so I could read them from the outside.

https://www.amazon.com/gp/product/B07GNMKYCZ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

I ended up buying 5 Lbs of Wisedry bulk Silica gel beads, which came with 10 small mesh bags. I put 200 grams of beads in four of the bags, one per dry box.

https://www.amazon.com/gp/product/B07QRRHJV3/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

I dehydrated 8 reels in my Bosch convection oven for seven hours at 120 Deg F and 16% relative humidity (oven has a dehydration mode). I put those reels in two of the boxes, and the humidity after one hour read 18% in both boxes. After two days both boxes read 10% humidity. For the other eight reels I did no pre-drying in the oven, and the humidity started out at 38% and stayed at 30% for one day, and after three days they read 21% and 19%. I think they are still going down slowly, and ultimately will reach 10% too. I designed a rack system for the boxes, mounted on one of the panels of my garage door (pic), and, yes, the door still opens fine with the boxes in place.

Relative to printing with filament at 10% humidity: It does, indeed, print better. Excellent first lay adhesion, and very solid layer-to-layer strength. And yes, some very old filament that had deteriorated to the point that I could no longer use it reliably now prints like it is new.

RE: Filament: How Dry Is Dry Enough???

I found these bags with a vacuum pump on Amazon.  They are holding the vacuum pretty well.  I am sure you can find them worldwide.

http://3dprinterreviewblog.com/2021/03/27/duplicated-sovol-3d-sealed-vacuum-storage-kit/