Also I Injection mold Acetal (Delrin) all the time if you need assistance with your project.
Thanks,
Pete

I tried this a while ago in ABS. But you have to have a lot of powder mixed in to really get any color or effect.
Remember that when used in carpaint you spray a thin layer on top of the base color to get the effect, so all pigment is concentrated in a thin layer on top.
Mixing with pellets and extruding you mix INTO the plastic. So very little is seen on the outside of the filament.

Also, a blue pearlescent should be ontop of preferrably a white base not blue to get that shimmering effect.

The dry pigment is from eBay, here is the link:

http://www.ebay.com/itm/Brilliant-Blue- … mp;vxp=mtr

The picks do not have that "pearlescent" finish which I expected but the color is OK. Maybe the flat pearl flakes got ground up in the filastruder to a smaller size? Or the milky white acetal resin mutes the pearl sheen? I don't know.
I am just happy that I was able to extrude and pelletize the acetal successfully. I am going to try some " Glow-in-the-Dark" pigment powder next. I will post those results.

I extruded some acetal filament today with some success. First of all I want to make clear that I am doing this for use in injection molding and do not intend to use this acetal for 3D printing.  I bought a few pounds of acetal pellets from an eBay seller who stated that they were for injection molding. I tried to get more information from him on the pellets after the purchase but I got no response. I made some guitar picks from the natural resin pellets and they came out very nice.
Today I added 5% Blue Pearlescent dry pigment to the pellets and mixed well by shaking and turning the container.
I started out extruding at 185 degrees and the filament was very porous due to decomposition and gassing of the acetal polymer.  I gradually backed the temperature down to 168 degrees and the gassing of the acetal stopped. The shape of the filament is a very odd pear-shape as you can see in the photo. I used the 3mm nozzle and the filament at the widest point is about 2.50 mm to 2.6 mm wide. The Filawinder wound it on the reel  just fine. I think that the air blowing from the cooling fan is causing the odd shape. It almost looks like the filament flattened out and folding in on itself as there is a hole in the center.
I stopped the cooling fan at one point and the filament really stretched out terribly. Maybe try to go even lower with the temperature next run? In spite of the odd shape it pelletized well and the color seemed very evenly dispersed. The pellets are very usable and I will try to make some picks from them tomorrow.