I wasn't quite sure where to post this, as it's not quite a mod and I didn't make it on a BigBox either, but it is FOR my BigBox, so.... here it is. A couple of things I'm really looking forward to printing with on my BigBox are soluble support and nylon. However both E3D's Scaffold and nylon are quite hygroscopic and will absorb water rather readily from the atmosphere, so I created a simple sealed box to hold the spools while printing. What you will need: A suitable container that will fit the size of spools you want to use. I was going to make two single reel boxes, but couldn't find anything both tall and wide enough, so in the end I used a larger box that can hold two spools. The box I used was this one: https://www.amazon.co.uk/gp/product/B001CMUOBK A length of M8 threaded rod slightly longer than the width of your box, 2x M8 nuts (ideally one Nyloc and one regular) and 2x M8 washers Some M4 and M5 screws, nuts and washers. I used M4 x 14mm and M5 x 6mm socket cap screws. Some threaded pneumatic fittings - M5 thread 4mm ID. One for each spool/filament exit point. Some PTFE tubing 4mm OD 2mm ID (Bowden tubing) A suitable dessicant. I use reusable silica gel in a fine nylon mesh bag, with some indicator gel mixed in so I can see when it needs drying out. Optionally a hygrometer. I used this one: https://www.amazon.co.uk/gp/product/B00CGZYFO4 Bearings for spool reels. 2x 608ZZ for each large spool reel, 2x 688ZZ for each small spool reel. Printed parts: 2x axle plate inner, 2x axle plate outer 1x filament plate inner and 1x filament plate outer for each spool and filament exit point 1x axle spacer Suitable spool reels. The large size fits most spools with 50-55mm inner hubs, e.g. E3D, ColorFabb, 3DPrima, eSun. The small size fits Taulman spools. The STL is for half a reel so you will need two for each spool. Optional - 2x M8 wingnut Optional - x3 dessicant retainer inner bar and x2 dessicant retainer outer plate Optional - x2 hygrometer mount inner and 2x hygrometer mount outer Putting it together is pretty simple. Work out the centre point of your spool and drill an 8mm hole in each side of the box for the threaded rod. Mount the axle outer plates and mark the holes then drill 4mm holes for each screw. Press M4 nuts into the recesses in the inner plate, and screw the inner and outer parts together. For the filament plates, decide where you want the filament to exit. I actually installed two for each spool, one that comes out the side and one that comes out the top to make it easier to guide the filament to different extruders. The outer plate has an extra hole in the bottom of the T, this is to put a short M5 screw in to swap for the pneumatic fitting and cover up the hole when it's not in use. Drill a 2mm hole for the filament, then put a small piece of scrap filament through and use that to align the inner plate, then mark the two holes at the sides of the T and drill 4mm holes. Don't drill a hole for the bottom hole in the T. Press M4 nuts into the two recesses in the inner plate, and M5 nuts into the recesses in the outer plate. Mount the outer plate with the nuts against the box wall, screw the inner and outer plates together and fit the pneumatic fitting and spare M5 screw. The M5 screw needs to be very short, I used 6mm. If you want to make it a bit fancier (and I'm sure someone told me that if something's worth doing, it's worth overdoing...) you can add a few other bits and pieces. I added some inner bars to hold my bag of silica gel in place. If you want to use these you'll need to scale the bars horizontally to fit your box. My box tapers so they are slightly different lengths, but you can just use a longer screw to hold them so it's not too critical to get the length exact. I also put in a mount for a small hygrometer since I had a bunch of them lying around from trying to track down a damp problem and balance my central heating. It helps to check that the box is staying tightly sealed but isn't really necessary if you use indicator silica gel. When you want to print with it, just push a spare length of PTFE tube into the pneumatic fitting and use that to guide the filament to your extruder. When you print the parts with the nut recesses, you may need to scale them slightly or tweak extrusion to suit your printer so that the nuts press in tightly. My K8400 isn't the most accurate with small holes so the tolerances on them are quite large. The STLs are also simple enough that 123Design should be able to convert them back to solids if you want to adjust them that way. None of the parts need any support, I printed them in PLA with 30% infill.