This is where things got a bit squiggly… Flexibles. After the joy and simplicity of using hard plastics I figured this would be equally easy and intuitive. Boy was I in for a surprise.

I continually failed at this for weeks. Here is a summary of my learnings from trying to push a wet piece of spaghetti through a 250 degree 0.4mm hole to make cool fly stuff.

Use a slicer that makes intuitive changes:

The Prusa slicer was fantastic for hard plastics, but as it turned out, the overrides make any change to extrusion very difficult to adjust, and confusing to understand in result.

Extruders don’t like wet spaghetti:

The Prusa would jam almost every print. Granted, I was using extremely soft TPU based filaments, but eventually I was spending more time loading/unloading/unclogging than I was printing. The geared filament path just wasnt built for flexibles.

Red showing where the flexible filament would go (instead of down to the hotend)

I needed a more direct filament path. I first tried ordering a Flexion extruder, but after much messing around and waiting eventually found the Omniadrop extruder. This extruder is specially designed for flexibles, with no way for the filament to escape during feeding. And to date, I haven’t had a single jam.

The Omniadrop 2.1 (direct drive extruder with short filament path)

My first cube test with the Omnia, 80 Shaw Flex:

But I was starting to learn that there was no silver bullet to this. I still had underextrusion, and the Prusa slicers weird series of overrides made any changes hard to understand. In search of something more intuitive, I ended up on Simplify3d. I could visually track and adjust things like stringing, and all my changes could be seen in real time and tested on prints.

And finally. Some success.

Simplify3d and the infill pattern I found best. For now I’ve stuck to single layer prints.

The final tweaking was in temperatures and infill pattern settings. I’m proud to say I can now make some pretty awesome components.

Lastly, first layer adhesion seemed to work best on smooth sheets (not satin). To avoid the flex destroying the sheets I found the old wood glue trick works best. Some wood glue and water spread on the surface. It also means it can be washed off with dish detergent.

My preferred glues to use (to create a removeable bed surface with good adhesion). Omnia 2.1 extruder in background.

Dyed TPU crabs


  1. If you’re having fun 3D printing Fly parts then I suggest you obtain a small Laser Cutter/Engraver like the ORTUR Laser Engraver, Laser Master 2 S2 LF. I’ve had one since the summer of 2022 and I’ve cut fly parts out of EVA craft Foam in 2mm, 4mm, 6mm and 10mm foam for floating and suspending flies, Ultra suede for twister tails, crab and crayfish bodies, silicone sheet material for bodies of all sorts and clear acetyl sheet for spoon flies and diving lips. All you have to do is draw the shape in any graphic software like Inkscape software which is free and then convert it to SVG format to drive the laser. If you care to send me your email address I would be glad to send you a sheet with all of the shapes that i’ve drawn and if you found any of interest I could email the .SVG files to you to cut on a laser cutter.


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