Suction cups and blowouts (volcanoes) in hollow resin prints
A blowout or 'volcano' is a ruptured wall, crater or crack on a hollow or cup-shaped part. When an enclosed cavity faces the FEP, each peel creates a vacuum (a suction cup) that stresses the walls. Trapped resin can also push its way out later.
Most likely causes (in order)
- Hollow model with no drain/vent holes: With no way for air and resin to move, every lift pulls a vacuum inside the part.
- Cavity facing the FEP: A cup shape open towards the film behaves like a plunger.
- Trapped uncured resin: Resin sealed inside can leak or crack the part after curing.
Settings to change
| Setting | Change | Why |
|---|---|---|
| Hollowing | Add at least two drain holes (one near plate, one far) or print solid | Prevents suction cups and trapped resin (Lychee: Volcanoes). |
| Orientation | Orient so no enclosed cavity faces the FEP | Cups create vacuum during peel. |
Exact values depend on your printer and resin. Start from the resin maker's recommended settings and change one thing at a time.
Quick checklist
- Add at least two drain holes: one near the plate, one far from it
- Or print the model solid if it's small
- Reorient so no enclosed cavity opens towards the FEP
- Rinse and drain the inside thoroughly before curing
FAQ
What is a suction cup in resin printing?
An enclosed hollow space that faces the FEP. Each time the plate lifts, it pulls a vacuum inside, which can deform, crack or tear the print.
How many drain holes does a hollow print need?
At least two, so air can enter while resin drains: one near the build plate and one further away.
Should I just print minis solid?
Small minis are usually printed solid. Hollowing mainly makes sense for larger pieces where it saves resin.
Not sure which one you've got?
Upload 1–4 photos of the failed print and PrintCleric ranks the likely causes and tells you exactly which settings to change, with sources.
Sources
Related fixes
- Layer separation / delamination in resin prints
- Failed supports: model stuck to the FEP, only supports printed
- Nothing on the build plate (print stuck to the FEP)
- Elephant's foot (flared bottom layers)
- Blooming and over-exposure: soft details and rough surfaces
- Cracking resin prints (hollow parts and post-curing)
Wear nitrile gloves and eye protection when handling uncured resin, and work in a ventilated space.