YouTuber Develops Homemade 3D Printing Pen with Hotend, Specializing in Repairing Cracked Parts

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March 24, 2026 News 9989

What to do when a 3D printed part cracks? Conventional 3D printing pens are slow, have poor temperature control, and don't bond securely.

The YouTube channel "half-baked-research" decided to take matters into their own hands, building a 3D printing pen that can "weld" plastic.

Principle: Attach a Hotend

The main reason ordinary printing pens perform poorly is poor nozzle heat conduction. The developer directly replaced it with a standard brass hotend from 3D printers—heat transfers precisely, melting not only the extruded material but also the plastic on both sides of the seam, achieving true plastic welding.

Upgrade: Faster Extrusion, Like a Hot Glue Gun

They also modified the extruder, housing it in a shell reminiscent of a hot glue gun, with material feed speed far exceeding ordinary printing pens. Higher heat + greater flow significantly improves repair efficiency. In appearance, it更像 a "small plastic extrusion gun."

Testing: Far Superior to Glue, Approaching Hot Air Welding

Load tests show:
Much stronger than ordinary 3D printing pens.
Even more advantage compared to superglue.
Slightly inferior to hot air welding, but hot air can easily damage thin-walled parts.

This homemade hotend pen offers precise control, making it especially suitable for repairing delicate printed parts.

From "sticking" to "welding"—this is the right way to approach 3D print repair.