This is the first post in a troubleshooting series I’m building as I run into (and fix) the classic 3D printing problems. First up: the clogged nozzle, probably the single most common reason a print just stops extruding.
How I tell it’s actually a clog
A clog usually shows up one of two ways: the extruder motor keeps clicking or skipping while nothing comes out of the nozzle, or filament extrudes in a thin, weak trickle instead of a full stream. If the extruder is turning normally and filament is feeding smoothly into the hotend but nothing (or almost nothing) comes out the tip, that’s a clog, not a mechanical problem upstream.
The quick fixes I try first
- Temperature check — the most common cause of a “clog” that isn’t really one. If the nozzle temp is a few degrees too low for the filament, it won’t flow properly. I bump it up 5–10°C and try again before doing anything else.
- Cold pull — heat the nozzle to printing temp, then let it cool to around 90°C while applying gentle pressure on the filament, then pull firmly. This often drags out the exact bit of degraded plastic that was blocking the tip.
- Manual extrude test — using the printer’s menu to extrude a short length at temperature tells me immediately whether flow has improved.
The cold pull fixed probably 80% of the clogs I’ve run into. It’s always my second step, right after checking temperature.
When it’s a full jam, not just a clog
If a cold pull doesn’t clear it, I’m usually dealing with a harder jam — often caused by leaving filament heated and idle for too long, letting it slowly degrade inside the hotend. At that point I’ll do a proper nozzle removal and clean it with a cold pull performed outside the printer, or replace the nozzle outright if it’s an inexpensive brass one.
What actually prevents this
Most of my clogs traced back to leaving filament loaded and hot for long idle periods, or switching filament types without a proper purge. Now I always run a full cold pull whenever I swap materials, and I don’t leave the hotend sitting at temperature for more than a few minutes without printing.
A clogged nozzle is annoying but almost always fixable without buying anything. If you’ve tried a cold pull a couple of times and you’re still not getting flow, it’s worth checking that the filament itself isn’t the problem — damp or brittle filament can mimic a clog convincingly.
