coloring PLA filament by passing through body of Sharpie?

[jbeale 0]

I thought this article was very interesting, and the results look convincing:

http://3dprint.com/3340/ulimate-filament-colorer/

Is this possible with UM2? It uses 3mm instead of 1.75mm filament (need larger diameter marker?) but it also has a bowden tube; would that make a difference?

Apparently it works better on "natural" color filament, than "white" for some reason.

 

[kolia 31]

http://www.thingiverse.com/thing:77424

http://www.thingiverse.com/thing:11742/

http://www.thingiverse.com/thing:11236

Now I don't have an UM2 but in any case I guess you would have to either color your filament before printing, even with a fixture to help it, but still doing by hand, OR while printing, by installing the fixture right before the feeder, making sure the friction due to the pen is minimal.

I don't think you need to color it perfectly for good results. I used to make just black dots at regular step on a white filament to easily monitor its progress in the bowden tube, and just this was already affecting the rendering of my print.

 

[anon4321 16]

The issue will be the dilution of the ink due to the larger volume of the filament. 2.85 filament has a area of 6.38 vs 2.41 for 1.75. 2.85 has a circumference of 8.95 vs a circumference of 5.5 for 1.75 filament.

So 2.85 has 2.65 times the volume of 1.75 filament but only 1.63 times the area to coat with the ink. So I think this means that the ink to filament ratio for 2.85 filament will be 62% of the ratio for 1.75 filament.

I did this math without coffee so to might be off but the general point is that there will be less ink per given volume of filament for the 2.85 size.