hello,
You used copper pipe in extruder, but copper is soft material how can it will be harden, let me know
I’ve used brass, not copper. But indeed a soft material as wel…
In the blueprints In mentioned that this is definitely not a necessity, in fact if I would build another one I wouldn’t go for brass but probably stainless steal.
Good luck!
Would love to see your project!
Send me a picture 
Hi Dave. We just want to share our 3D-printer-wire project. It’s inspired in yours. We believe in your project since the first time that we saw it, it was very motivating. My colleague and I was thought that this prototype could be builded (may be) by the entire world, just like yours, because of the simplicity materials that it uses. Later we’ll send you a picture of this project. Thanks a lot for your inspiration and let’s work on plastic.