Dyeing filaments - PETG, PVB, Nylon, PLA ?  

There is another way: 

You can get quite a strong 'stained glass' effect by starting with clear filament.

Cheerio,

RE: Dyeing filaments - PETG, PVB, Nylon, PLA ?

@diem - thanks for this - I was considering how to apply the dye as the filament rolls off the spool. The marker hack produces a nice result (just need to make an adapter for MK4/MMU3).

That said, I am still looking at ways to increase the pigment infusion into the filament if I can to get bolder color: using a hygroscopic filament like PVB, I can get the dye to soak through almost to the core, and get some very strong, true color. 

So far, with PETG, I am only getting the dye around the outer ring of the filament (like the marker method, but a bit deeper), which results in a nice, stable looking color with translucent PETG, but with a solid PETG (like white), you can see that the blend is inconsistent, resulting in a lighter color and striping.

Posting a pic of my first dye job for reference here if someone else wants to try this. The dye was  red iDyePoly for synthetics ( https://www.jacquardproducts.com/idye-main). The top was a translucent PVB filament, the next a translucent PETG, the next a white PETG (note striping due to inconsistent blend, shallow dye penetration).

Ultimately, I'd like to get to the point where I can blend not just a nice color, but rather a specific color that can get me a consistent match to a hex color code. Mellonta tauta!

RE:

Update on this - if you want to try it at home with PETG, you must use the synthetic dyes. The RIT all purpose dyes (like these: https://www.ritdye.com/type/all-purpose-dye/) won't dent the PETG, even when it is heated to the point of deformation.