How to Fix Gaps and Pinholes in 3D Prints
Small holes or visible gaps in what should be a solid top surface, sometimes letting you see the infill pattern underneath through tiny openings.
Common causes
Not enough top solid layers
If there aren't enough fully solid layers on top, the surface can't completely bridge over the infill gaps below.
Infill percentage too low
Sparse infill leaves larger gaps for the top layers to span, which is harder to close completely.
Under-extrusion
Even with the right layer count, not enough plastic flowing means those top layers can't fully close the surface.
Low infill/perimeter overlap
If the overlap between infill and the outer walls is too small, tiny unbonded seams can appear as pinholes.
How to fix it
Increase top solid layer count
4-6 top layers is a common starting point at a 0.2mm layer height — increase further for lower infill percentages.
Increase infill percentage or density
Denser infill directly underneath gives the top layers less distance to bridge, closing gaps more reliably.
Fix any under-extrusion first
Check nozzle temperature, extruder grip, and filament diameter settings — see the under-extrusion guide.
Increase infill/perimeter overlap
A slightly higher overlap percentage in your slicer ensures those seams fully bond together.
Still stuck?
ForgePrint diagnoses the exact cause for your printer and filament — describe it, or just upload a photo.