How to Fix Stringing: The Complete Guide to Clean Prints

What Is Stringing?

Stringing happens when your printer leaves thin plastic hairs between parts of your model during travel moves. It's purely cosmetic on most prints — but on complex geometry with many islands or towers, it can ruin the result entirely. The good news: it's almost entirely fixable through slicer tuning.

Why It Happens

During a travel move (when the print head moves without extruding), filament shouldn't come out. In practice, it leaks. Hot filament is less viscous and oozes through the nozzle. The amount depends on temperature, material, and how well your retraction settings are tuned.

The Four Levers to Pull

1. Retraction Distance

This is how far the extruder pulls filament back before a travel move. The further it pulls, the less pressure there is at the nozzle tip — and the less it oozes.

Bowden extruders: Start at 4mm. Most work well between 4-6mm. Too much retraction causes jams and gaps.

Direct drive extruders: Start at 0.5mm. Usually 0.5-1.5mm is enough. The filament path is short, so you don't need much.

2. Retraction Speed

How quickly the filament is pulled back. Too slow and it oozes during retraction. Too fast and the extruder gear strips the filament.

Good starting point: 35mm/s. Range is usually 25-45mm/s. Tune in 5mm/s increments.

3. Temperature

Hotter filament flows more easily — and oozes more. A 5°C drop can significantly reduce stringing without affecting layer bonding.

PLA: If you're at 210°C, try 200-205°C. Most PLA prints fine at 195-210°C.

PETG: Naturally stringier. 230-240°C is typical; dropping to 225°C can help but watch for under-extrusion.

ABS/ASA: 240-260°C. Higher temps needed for layer bonding, so focus on retraction tuning instead.

4. Travel Speed

Faster travel means less time for oozing. If your printer can handle 150mm/s+ travel without layer shifts, use it. Some printers max out around 100mm/s — that's fine, work with what you have.

The Tuning Process

Print a stringing test model (there are many on Printables and Thingiverse — towers connected by gaps). Run one test at default settings, then adjust one variable at a time.

Step 1: Lower temperature by 5°C. Test.

Step 2: Increase retraction distance by 0.5mm. Test.

Step 3: Adjust retraction speed by 5mm/s. Test.

Keep a log. When you find settings that work, save them as a filament profile.

The Secret Weapon: Dry Filament

Moisture in filament causes steam bubbles during extrusion. Those bubbles expand and force filament out during travel moves. If your retraction is tuned and you're still stringing, dry your filament.

PLA: 45-50°C for 4-6 hours in a filament dryer or dehydrator. PETG: 65°C for 4-6 hours. ABS/ASA: 80°C for 2-4 hours.

Advanced Slicer Features

Wipe while retracting: The nozzle wipes against the last printed perimeter during retraction. Catches ooze on the model where it's less visible.

Coasting: Stops extrusion slightly before the end of a perimeter, using the pressure in the nozzle to finish the line. Reduces pressure before retraction.

Z-hop: Lifts the nozzle during travel moves. Can actually increase stringing on some machines because the filament stretches. Test with and without.

Deretraction extra length: Some printers benefit from pulling back slightly more than they push forward. Can compensate for filament compression. Usually 0-0.5mm.

Material-Specific Notes

PLA: Easiest to tune. Low shrinkage, good cooling response. Most PLA should print string-free with decent settings.

PETG: Naturally stringy. Accept that some fine hairs will appear — they pull off easily with fingers or a heat gun on low. Focus on temperature and retraction balance.

TPU: Stringing is hard to avoid completely. The flexible material stretches during retraction. Use a direct drive extruder, slow retraction, and accept minor cleanup.

Nylon: Stringing varies by blend. Dry thoroughly, tune temperature carefully. Some Nylons (PA-CF) string less due to fiber content.

When Nothing Works

If you've tried everything and still get heavy stringing: check your nozzle. A worn nozzle with an enlarged tip or burrs will string regardless of settings. Replace it — nozzles are cheap. Also check your PTFE tube in the hotend; if it's degraded or not seated properly, filament can accumulate and ooze.

Quick Reference

Bowden: Retract 4-6mm at 30-40mm/s. Direct drive: Retract 0.5-1.5mm at 25-35mm/s. Lower temperature. Dry filament. Use wipe/coasting if available. Print test models and tune systematically.