Testing solution for thicker materials in 2ft+ tube

had some problems with thicker clay, couple pics here.
managed to get the stock tubing through od 8mm id 5mm polyurethane tubing by putting 1.7mm filament in the stock tubing and feeding the filament through the urathane tube then pulling/pushing the stock tubing through the polyurethane tubing for a very tight fit.
used silicone based grease for the last part, picked the 8mm polyurethane tubing up at lowes.

How are the results using this method? What issues did you face before deciding to reinforce the tubing?

Thanks for posting the idea!

tubing expanding instead of extruding, only happens with more viscous materials.
It would cause lots of problems extruding clay especially over control of the print as well as bursting tubes and poping the tube off the luer lock on the syringe.
haven’t tested it yet but i’m pretty sure it will do the trick, but now the problem might be in bracing the plunger part of the syringe so it doesn’t bend/twist under that amount of force. was planning to make and print re enforcement splints for it.

but other hobbies have taken priority for now.

First clay tests with double tubing went very well, the prints turned out great, and extrusion was a lot more controlled.
honestly a little suprised how much better it is. so might just want to invest in some id:3.5mm ptfe tubing…

Hi, @cor5151,

This looks like a good idea, have you had any further developments in the type of tubing you are using? Can you or @fink provide what the ID and OD of the stock tubing shipped with the unit is?


Yes, I’ve just used PTFE tubing that is much stonger, standard 3mm filament bowden tubing worked great. tubing connectors worked perfect on it as well.
This is the exact tubing I have:

the original post was just kinda a quick fix to get it right, but i’m sure it has its place.

Hi @cor5151 and all.

First off, wicked prints! Charmander and Bulbasaur look great. We have switched over the tubing in our kit to another flexible material that does not have the balloon effect under the large load. We are exploring some different tubing options that may also work well for various different materials.

FYI @bholness , as long as the ID is 1/8" the connectors we use will work.