Hey! We’ll get rid of those **PETG strings/wisps** even if you’ve already tuned retraction. First, a quick scan so we can rule in/out **hotend thermal creep**:
• Printer & hotend: direct drive or Bowden? All-metal heatbreak or PTFE-lined? Nozzle size (0.4/0.6).
• Slicer & profile: **PrusaSlicer/Cura/Bambu Studio**? Current **retraction distance/speed**, **combing**, **coasting/wipe**, **Z-hop**, **pressure advance / Linear Advance (K-factor)**.
• Temps & speeds: nozzle/bed temps, **travel speed**, first layer temp, and **part cooling** percent.
• Filament: **PETG dryness** (dryer used?), brand/age, spool stored with desiccant?
• Symptoms: fine hairlike strings, **nozzle ooze during travel**, blobs/zits at **Z-seam**, or jam after long print (classic heat-creep sign).

Thanks — classic **PETG stringing with thermal creep overlap**. PETG likes higher temps and oozes easily. In **all-metal hotends**, heat can creep up the heatbreak, softening filament higher than intended. That increases **nozzle pressure** and slow ooze during travels, even with proper retraction. We’ll tackle both sides:
1) **Thermal management** (heatsink fan, heatbreak contact, paste, shroud alignment).
2) **Slicer controls** (retraction tuning for direct drive, coasting/wipe, minimum travel after retraction, combing/avoidance, travel speed).
3) **Material factors** (**PETG moisture**, nozzle size/flow, temperature tower) so you don’t get under-extrusion when dropping temp.

Simple checks to differentiate **heat creep** from pure retraction issues:
• After a 10–15 min **heat soak** at 230–240 °C idle, try retracting by hand. If the filament feels **chewy/swollen** above the melt zone or pulls out with a long **tapered bulb**, that’s heat creep.
• Inspect the **heatbreak**: ensure tight cold-side fasteners, correct **nozzle-to-heatbreak gap** (hot-tighten at 240 °C), and use a pea-sized amount of **thermal paste** on the heatsink side only (not in the melt zone).
• Verify the **heatsink fan** is 100% duty, blowing the right direction, no dust in fins, shroud not blocked by the part cooling duct.
• Do a **cold-pull**: if the pulled filament shows a long softened section well above the nozzle, the heat transition zone is too tall (heat creeping up).

For **direct drive PETG**, start here (PrusaSlicer/Cura/Bambu names in parentheses):
• **Retraction**: 0.6–1.2 mm @ 25–40 mm/s (PrusaSlicer: *Length/Speed*). PETG dislikes long/fast retractions that grind material.
• **Wipe/Coast**: Enable a modest **wipe** (2–5 mm) and **coasting** (~0.1–0.3 mm³ for 0.4 nozzle). This relieves pressure before travels.
• **Combing/Avoid crossing perimeters**: Prefer **Combing = Not in skin** (Cura) or enable **Avoid crossing perimeters** (PrusaSlicer) to reduce string spans.
• **Minimum travel after retraction**: ~1.0–2.0 mm so the slicer doesn’t over-retract on tiny hops.
• **Travel speed**: 180–220 mm/s if mechanics allow; faster travels reduce ooze time.
• **Z-hop**: Off or minimal (0.2 mm) — big Z-hops extend hot dwell time and encourage ooze.
• **Linear Advance / Pressure Advance**: Calibrate **K-factor** (Marlin) or **PA** (Klipper). Proper pressure control reduces blobs/zits at the **Z-seam**.
• **Seam painting / Random seam**: Hide the seam or align it on a back edge to mask tiny zits.
• **Wipe into infill** (PrusaSlicer) and **Combing within infill** (Cura) also help.

Yes — for most PETG a **230–250 °C** tower in **5 °C steps** works well. Print at your real speeds (perimeters ~60–80 mm/s) so results are meaningful. Pick the lowest temp that gives clean bridges and good adhesion, then combine with the retraction/wipe changes above. If you’re still forced too hot due to **volumetric flow**, consider:
• **0.6 mm nozzle** to reduce back-pressure at the same part strength.
• Lower **max volumetric speed (MVS)** in slicer (e.g., 8–10 mm³/s for generic PETG) so the hotend isn’t over-run and forced to run hot.
• Ensure **nozzle is sealed** (hot-tightened) — micro-leaks cause blobs that mimic stringing.

**Moist PETG** absolutely increases **oozing and micro-stringing** even without loud popping. Quick wins:
• **Dry** 55–65 °C for 4–6 h (per manufacturer), then store with **fresh desiccant** in a sealed bin.
• Keep **part cooling** modest (20–40%) — too much can weaken layer bonding, but a small amount reduces surface tack that grabs strings.
• Verify the **heatsink fan** is fixed at 100% and not PWM-ed by firmware; PETG benefits from a stable, cool heatbreak to prevent creep.

A few durable upgrades/maintenance steps:
• Replace worn **heatbreak** with a polished, low-friction all-metal unit (bimetal if available).
• Use a quality **heatsink fan** (ball-bearing, ≥0.15 A) and ensure shroud alignment; add a silicone **sock** on the heater block to shield radiant heat.
• Confirm **nozzle–heatbreak stack**: insert nozzle, leave ~0.5 mm gap to block, then screw heatbreak to touch; finally **hot-tighten** at 240 °C.
• Keep **PTFE guide** above the heatbreak short and square (if used); swap to **Capricorn PTFE** for better heat resistance in Bowden sections.

Great approach. Create two **PETG profiles**:
• Clean PETG: lower temp by 5–10 °C from strength profile, **wipe+coast on**, **avoid crossing perimeters**, travel 200 mm/s, **Z-hop off**, seam hidden.
• Strong PETG: slightly higher temp for adhesion, **coast minimal**, slower perimeters, modest part cooling (20–30%).
Keep **Linear Advance/Pressure Advance** identical across both to avoid seam drift, and set a **max volumetric speed** that your hotend can sustain without pressure spikes.

Summary: Stubborn **PETG stringing** is usually a combo of **thermal creep** and slicer pressure. Cool the heatbreak (fan/shroud, clean fins), **hot-tighten the nozzle stack**, dry the filament, then tune **retraction 0.6–1.2 mm**, **wipe/coast**, **avoid crossing perimeters**, fast **travel**, calibrated **Linear/Pressure Advance**, and a PETG **temp tower**. Need a hand applying this to your exact hotend/slicer? Open the chat.