Can I just glue the crack with CA?

For decor, yes. For function, no: the crack means ALL layer bonding in that area is weak, not just the visible line. Raise temp / lower fan and reprint.

Why do only tall parts crack?

The taller the part, the more accumulated shrinkage pulls at the layers and the more leverage any draught has. Short parts dump that stress into the bed.

Can wet filament cause cracking too?

Yes: moisture boils in the nozzle and the micro-bubbles weaken the layer weld, on top of leaving the surface porous. If the spool has spent months in open air (PETG and nylon especially), dry it before blaming the temperature.

Does adding more perimeters prevent the cracks?

It masks them: the part is stiffer and takes longer to split open, but the layer bond is just as weak. As a patch for one specific part it's reasonable; as a fix, no — the weld is fixed with temperature and fan.

3D printing troubleshooting

Layer cracking (delamination)

Also known as: the part cracks or splits along layers on tall prints.

The symptom

Tall parts develop horizontal cracks between layers, sometimes with an audible 'crack' mid-print. The part splits cleanly along those lines under stress.

Sources for this page: Prusa Knowledge Base · Manufacturer Simplify3D · Technical guide

Causes and fixes, ranked by likelihood

1

Printing temperature too low: the new layer doesn't remelt the previous one enough to weld.

Fix: Raise the temp 5-10 °C (within the filament's range). With thick layers and big nozzles, aim at the upper half of the maker's range.
Source: Simplify3D — Print Quality Guide: Layer Separation and Splitting ↗
2

Too much cooling or cold draughts: each layer cools before the next arrives (the classic on open-frame ABS/ASA).

Fix: For ABS/ASA: fan at 0-20% and an enclosure — check whether your printer has one in the compatibility matrix. For tall thin PLA, drop the fan from 100% to 60-80%.
Source: Prusa Knowledge Base — Layer separation and splitting (FDM) ↗
3

Layer height too large for the nozzle: lines barely touching.

Fix: Keep layer height under 80% of nozzle diameter (0.4 → max 0.32 mm). Beyond that, layer bonding falls off a cliff.
Source: Simplify3D — Print Quality Guide: Layer Separation and Splitting ↗
4

Background under-extrusion: with less plastic than intended, each layer touches less of the one below and the weld is only half made.

Fix: Rule out under-extrusion first (it has its own page): calibrate flow and check for partial clogs. No layer bond will ever be better than the amount of plastic forming it.

The material factor

ABS and ASA are the delamination kings on open printers: they shrink while cooling and layers pull themselves apart. Without an enclosure, stick to PLA/PETG for tall parts.

hotend tools that help here

Material compatibility → The matrix tells you whether your printer has what ABS/ASA/nylon demand (enclosure, temps) before you burn another spool on cracks. Cut STL for your bed → VERY tall parts: cut them into shorter sections with alignment dowels — fewer hours per print and less accumulated cracking.

FAQ

Can I just glue the crack with CA?: For decor, yes. For function, no: the crack means ALL layer bonding in that area is weak, not just the visible line. Raise temp / lower fan and reprint.
Why do only tall parts crack?: The taller the part, the more accumulated shrinkage pulls at the layers and the more leverage any draught has. Short parts dump that stress into the bed.
Can wet filament cause cracking too?: Yes: moisture boils in the nozzle and the micro-bubbles weaken the layer weld, on top of leaving the surface porous. If the spool has spent months in open air (PETG and nylon especially), dry it before blaming the temperature.
Does adding more perimeters prevent the cracks?: It masks them: the part is stiffer and takes longer to split open, but the layer bond is just as weak. As a patch for one specific part it's reasonable; as a fix, no — the weld is fixed with temperature and fan.

Sources & references

This page is cross-checked against public manufacturer documentation and reference technical guides:

Manufacturer Prusa Knowledge Base — Layer separation and splitting (FDM) ↗
Technical guide Simplify3D — Print Quality Guide: Layer Separation and Splitting ↗

Still stuck? Back to the quick diagnosis or check which materials your printer can handle.