I absolutely love my “filament spool transfer device” I found and printed from another site I will not mention here.

The only problem I had was the donor spool would try to spin out of control and make a mess. It also would not keep tension on the filament to make it layer evenly.

I went into fusion 360 and designed this brake for the donor spool to keep it under control.

You will need a sheet of 3mm silicone from amazon:

https://www.amazon.com/gp/product/B09NX8GX5K/ref=ox_sc_act_title_1?smid=ACN533ICAIGKY&psc=1

M3x20 bolts (8)

M3 nuts (12)

One of the silicone brake holders is longer than the other two due to the difference in space from the frame when transfering 500g spools. You will only need to print one of these as only one side changes in distance.

When assembling you will need to make sure the brake sits slightly forward of center of the donor spool.