Since you are trying so many different plastics, I would make a Filastruder set up that is driven by a 1/2 in drill with a variable speed controller on the line side......Or perhaps a modified cheap drill press.

It might be worth thinking about since you are experimenting in so many different plastics, and you would be able to tweak RPM as well as temperature, as you already have a 15v supply on the heater.

I can  see why you prefer Slic3r, as it is easier to change filaments, but for me, since I tinker with model airplanes, and need thin light weight parts, Simplify is giving me incredible parts that Slic3r cant do.

keep your progress posted, I like to check see what you have going on from time to time.............

Best of Luck !

If anyone wants to try some of this to see if it works for you, send me a PM and I'll send you some, no charge as long as you let me know what you find. I have 20lbs of this stuff that I can't use until I figure out what's going on. Shoot, I don't even know if it can be used for printing without clogging my nozzle.

It still has a rough texture, but although it is rough it at least has a more consistent diameter. Looking at closer to something like 0.10 now, which is better than before.

I'm still using the modified nozzle with a steal tip (2.8mm diameter, if I remember correctly)

As for Simplify 3D, I have tried it before and I find it to be aggravating since I use so many different plastics (Store-bought PC, Filastruder PC, Filastruder PC-ABS, Nylon, Nylon Bridge, ABS, HIPS, etc etc). Plus I'm using it on two different printers with two different build sizes. I didn't find the settings to be as easily changed as Repetier, which I can select from a drop down menu with Slic3r. I'm also using a raspberry pi for Repetier-Server so I can have the printers untethered from my workstation.

Which leads me to my original post of trying a small orifice, as I suspect a feed rate issue.

With the plastic having fiberglass fibers, you might have a problem with controlling the viscosity by temperature.

What does the tip look like? is it completely insulated? or, is this the tip that was modified?

That's my 2cents.

I find what you are doing with plastics is really fascinating, Check out Simplify3D slicer, my AirWolf3dXL is a brand new machine, best parts I ever seen.  (if you haven't already)

good luck !

When I started it back up, I got the same thing. See the picture below... It's really rough, with a diameter of 2.72mm +/- 0.20mm

After about 5 minutes of extrusion, it slowed way down and I got these blobs

Sorry for the bad picture quality. Maybe it's the lighting, but my phone didn't want to cooperate this morning.

I'm betting its a glass reinforced issue. You're sure that the old polymer is fully purged out? Did you remove the nozzle and drag the old polymer out?

Or the feed is not fast enough, that the hot plastic actually runs out faster than cold plastic can be fed in.

Perhaps try the 1.75mm nozzle to confirm this idea, and if that is the case, drive the filastruder with a variable speed drill motor......