Best Dry box implementation for direct drive printers

I want to build a dry box for my Tenlog TL-D3 Pro direct drive printer especially to help manage the moisture sensitivity of my PVA filaments during lengthy prints with dissolvable supports. I suspect this task is somewhat more straightforward in closed bowden tube printers where the inclusion of a dry box for the spools may mean the desiccant system has to do very light duty work to maintain the arid conditions over the entire filament. For my printer, however I am concerned about the constant exposure of the long segment leading into the extruder and the air exchange where the naked filament would exit the dry box. Has anybody had success enclosing some of a direct drive printer's filament path in tubing or is this effort doomed to interfere with the operation of the printer? I really don't want to rely entirely on attempting to bake or dehydrate the filaments after every print, especially if there is a chance of a print being long enough and the ambient humidity being high enough to spoil the the PVA before the print can even complete.

If you can identify a point on the frame of your printer at which the filaments move very little, consider to attach a bowden tube guide at that location. The tube would run to your dry box and protect the filament for as much of the travel as practical. Even if sitting idle, you'd have to dispose of a relatively short length. The amount of filament exposed during the print is not going to be too afflicted by exposure prior to printing.

I suspect you'll have a good quantity of desiccant available. I've found that a four ounce quantity of fresh beads lasts less than a month before requiring refreshing, when used in a sealed bin, in my case a Sterilite plastic bin with latching gasket lid. Probably not watertight, but economical enough.

what do you think of this design?

https://www.thingiverse.com/thing:3065301

It seems to be designed with direct drive printers in mind. I'm not sure where to get the rods but a visit to local building supplies store may dig something up.

That appears to be well designed. I'd expect you can get the rods and bearings via Amazon or eBay or many 3D printing sources. 8 mm steel rod is not uncommon.

Done this a fair bit. What you're looking for is what's commonly known as a reversed bowden. An additional benefit is that if the filament is hard to pull from the spool, it doesn't transfer the force through the extruder and X-gantry. Instead the force is directed back to the start of the bowden tube.

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Originally Posted by minneapolis-matt

what do you think of this design?

https://www.thingiverse.com/thing:3065301

It seems to be designed with direct drive printers in mind. I'm not sure where to get the rods but a visit to local building supplies store may dig something up.

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Looks pretty decent. If you've got the room - can;t see any reason why not.
Also the box is large enough to use the cheap re-useable desiccants in.

My current plan with soluble filament is to just wind what i need on a small spool that gets kept in a sealed bag.
And not expose the main reel to atmosphere for any length of time.
But if the printer is in a humid environment, I can see where the drybox would be a good idea.