My nozzle is clogged
A clog is rarely just bad luck: it is usually damp filament, charred residue from a previous material or a worn nozzle. Before dismantling anything, it is worth checking whether the clog is at the tip or higher up, in the heatbreak.
What the failure looks like
The extruder clicks or slips, very little or no material comes out, and the part becomes hollow above a certain height. In a partial clog, the flow drops but does not stop completely.
Causes, most likely first
- 01
Charred residue
Printing at high temperatures or leaving hot material idle burns the plastic inside the nozzle.
- 02
Material mixing
Switching from PETG or ABS to PLA without purging leaves residue that degrades at the new material's temperature.
- 03
Heat creep
Heat creeps up the heatbreak and the filament softens prematurely. Typical in hotends with a dirty or stopped heatsink fan.
- 04
Damp or dusty filament
Dust from the spool enters with the filament and accumulates.
- 05
Worn nozzle
With abrasive filaments (carbon, glow, wood), the brass nozzle wears down in just a few dozen hours.
Step-by-step fix
1. Check the heatsink fan first
If it isn't spinning, you have heat creep and the clog will return even if you clean it.
2. Try pushing by hand
Heat to printing temperature, release extruder tension and push the filament by hand. If a thin, curled thread comes out, it is a partial clog.
3. Cold pull (cold pull cleaning)
Load nylon or PLA, heat to 240 °C, drop to 90-100 °C for PLA (130 °C for nylon) and pull firmly. A plug shaped like the inside of the nozzle comes out along with all the dirt.
4. 0,4 mm brass needle
With the nozzle hot, insert the needle through the tip. Never when cold: you would snap the needle inside.
5. Repeat the cold pull until it comes out clean
Two or three times is normal. If the plug comes out black, there was charred material.
6. Replace the nozzle
If after three cold pulls it still fails, or if you print abrasives, replace the nozzle. It costs less than a wasted afternoon.
| Symptom | Probable diagnosis | Action |
|---|---|---|
| Extruder clicking and no material coming out | Total clog | Cold pull or nozzle replacement |
| Less material coming out than expected | Partial clog | Needle + cold pull |
| Always fails above the same height | Heat creep | Check heatsink fan |
| Started after changing material | Residue from previous material | Purge 10 cm at high temperature |
| Lines getting thinner over time | Worn nozzle | Switch to steel nozzle |
So it doesn't happen again
- Purge 10 cm of new material before printing after a filament change.
- Fit a hardened steel nozzle for filled filaments (carbon, wood, glow).
- Do not leave the hotend heated without printing for more than 10 minutes.
- Dry the filament if it has been out of the bag for months.
Related questions
Can I burn out the nozzle with a blowtorch?
It can be done, but only with the nozzle removed and bearing in mind that brass deforms easily. For the average user it is not worth it: a new nozzle costs less than the risk involved.
How often should a nozzle be replaced?
Brass with PLA/PETG: 300-500 hours. Brass with abrasives: 20-50 hours. Hardened steel with abrasives: 800+ hours.
Does hardened steel print the same?
It conducts heat less effectively, so temperatures are usually increased by 5-10 °C compared to brass.
Keep reading
What if it isn't worth your time?
Sometimes the part is more urgent than the learning curve. We're a workshop in Viladecavalls: send us the file and we'll print it with the right material and settings.
Still not working?
Tell Marco which printer and material you use and he'll tell you what to change.
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