3D printing with nylon trimmer line!

So I've seen a few people try this before (Credit goes to this article for having the most information on it I've seen) and decided to try it for myself. Not much to lose on my end, maybe a few nozzles if I'm unlucky, right?

I happened to have this lying around, and the 0.065" diameter happens to be fairly close to 1.75mm filament.

The stuff has been sitting on a shelf in our laundry room for about a year now, and being as impatient as I am I just took it straight to the printer, no drying whatsoever.

It extrudes! Quite enthusiastically, too; even after I manually retracted I still got maybe 15mm of ooze.

I went ahead and cleared my painter's tape off of my bed, covered it in 3DSystem's glass glue (don't judge, I had access to it and I figured it would be better than glue stick), and went straight into printing the ASTMD-IV strength test by moonj.

Slic3r ettings:
Nozzle at 230, bed at 80C, bare glass w/ Cube glue.
100% infill, 6 perimeters, 4 top and bottom layers.
40mm/s infill and perimeter, 30mm/s outer perimeter.
15mm brim.

It sticks!

It prints!

It finishes!

Towards the end I started getting quite a lot of crackling coming from the nozzle, probably because I didn't dry it in any way.

Initial impressions:
1. The stuff is really flexible. It's almost more of what I expected Ninjaflex to feel like rather than nylon.

2. Printing wasn't hard at all. I didn't get any warping (yet) and bed adhesion was quite strong on the Cube glue.
3. It's quite fluid compared to PLA when melted, meaning lots of stringing. The geometry of the thing I printed doesn't really give much of an opportunity for stringing, but I expect if you have multiple parts or multiple structures you're going to have quite a cobweb.

Of course, being so thin didn't make it really representative of nylon's properties, which is what I was after. I then decided to print the dayan zhanchi center cap by srepmub, scaled up 200%, simply because I had the model and it's a simple, solid geometric shape.

Also not a particularly hard print, but the raised tab deformed into a single blob because of how runny the melted nylon was. This time, though, I did get rather extreme warping:

It seems the thickness of the piece does help keep it quite a bit more rigid. While I can still flex it a fair amount, it takes a lot more force to do so and it doesn't come anywhere near the edge-touching-edge bend I was able to get on the other piece.

The amount of detail and "cleanliness" I can achieve with this material is nowhere near what I can do with PLA. Kind of expected, seeing as this wasn't at all designed for 3D printing.

Overall, I have quite high hopes for this material. Most of the tests I've seen done with this are more of the "this is possible" type rather than the "this is going to be one of my primary filaments" type, but for me I easily see this becoming one of my favorite filaments to print with and possibly replacing ABS for me outright. There are issues I will have to iron out, including the warping, stringing, and humidity, but once those are done this could be just as easy as PLA or any other standard filament.

(I will try Taulman nylons at some point. I'm sure they'll result in better parts, better finish, and easier printing. Right now, though, I just can't justify the price and would rather stick to this since, after all, it is still nylon.)

Update 9/20/2015: This stuff is TOUGH. Some of my friends and I spent an entire day trying to find various ways to destroy it, including bending it and stepping on it, bending it and clamping it in a vise, using two vises to tear it apart, etc. Nothing. Its tensile strength is superb, and because of how soft it is, it springs right back into shape no matter what we do. In the end, we finally took a saw to it and sawed it in half, but I doubt that would happen in a normal usage case.