The fine, cobweb-like threads or 'hair' that appear between parts of a print. They form when the nozzle travels from one point to another without printing and oozes molten filament, which solidifies into strands.

What's the #1 cause of stringing?

Badly tuned retraction. Retraction is the filament the printer pulls back before a travel move to relieve nozzle pressure so it doesn't ooze. If it's too short or too slow, threads appear. Tuning it with a retraction test is the most effective fix.

Does wet filament cause stringing?

Yes, a lot. Filament that has absorbed moisture causes severe stringing at any temperature: the water flashes to steam in the nozzle and drags plastic out. If you were printing fine and suddenly get threads, suspect the filament — dry it in a filament dryer.

Does lowering temperature help?

Yes. Filament that's too hot is more liquid and oozes more easily. Printing a 'temperature tower' tells you the lowest stable temperature for your specific filament, which usually reduces stringing noticeably.

Troubleshooting

Stringing: how to fix wispy threads in 3D printing

Your print comes out covered in fine threads, like cobwebs between the towers or letters. That's stringing, one of the most common — and most fixable — defects. Here are the four real causes, ordered by frequency, and how to fix each.

What it is and why it happens

Stringing appears when the nozzle moves from one area of the print to another without extruding, but oozes a bit of molten plastic along the way that solidifies into a strand. If you see "hair" or cobwebs between separate parts of your model, that's it. Good news: it's almost always fixed with slicer settings, not by buying anything.

1. Retraction (the #1 cause)

Retraction is the trick the printer uses to avoid oozing: before a travel move, it pulls the filament back to relieve pressure inside the nozzle. If retraction is too short or too slow, it doesn't relieve enough and threads appear. Fix: print a retraction test (a model with two towers), trying different distances and speeds until the threads disappear. It's the highest-impact setting.

2. Temperature too high

Filament that's too hot is more liquid and oozes more easily. Fix: print a temperature tower (a model that changes temperature in bands) to find the lowest stable temperature for your filament. Dropping 5-10°C usually cuts stringing a lot without losing layer adhesion.

3. Wet filament

This is the suspect many people overlook. Filament absorbs moisture from the air, and when melted, that water flashes to steam in the nozzle, dragging plastic out and causing severe stringing at any temperature. If you were printing fine and suddenly everything strings, suspect the filament. Fix: dry it in a filament dryer, and store it in airtight boxes with desiccant (silica gel). PETG and TPU are especially moisture-sensitive.

4. Low travel speed

Travel speed is how fast the head moves when NOT printing. The faster it crosses from one point to another, the less time the plastic has to ooze. Fix: raise the travel speed in the slicer; it's a safe setting that helps against threads.

Anti-stringing checklist

Retraction test → tune distance and speed.
Temperature tower → use the lowest stable one.
Sudden threads? → dry the filament.
Raise the travel speed.

Is your problem not threads but the part not sticking or lifting? That's a different defect: we cover it in why your print won't stick to the bed.

FAQ

What is stringing?: The fine, cobweb-like threads or 'hair' that appear between parts of a print. They form when the nozzle travels from one point to another without printing and oozes molten filament, which solidifies into strands.
What's the #1 cause of stringing?: Badly tuned retraction. Retraction is the filament the printer pulls back before a travel move to relieve nozzle pressure so it doesn't ooze. If it's too short or too slow, threads appear. Tuning it with a retraction test is the most effective fix.
Does wet filament cause stringing?: Yes, a lot. Filament that has absorbed moisture causes severe stringing at any temperature: the water flashes to steam in the nozzle and drags plastic out. If you were printing fine and suddenly get threads, suspect the filament — dry it in a filament dryer.
Does lowering temperature help?: Yes. Filament that's too hot is more liquid and oozes more easily. Printing a 'temperature tower' tells you the lowest stable temperature for your specific filament, which usually reduces stringing noticeably.