Resin print support marks and layer lines
Bumps, pits and fine lines left after removing supports, and stepped layers that show through paint. Clean cutting, wet sanding and a filler primer solve most of it.
Quick answer
Support marks are the nubs and pits where supports touched the print; layer lines are the fine steps between printed layers. Remove supports carefully (many people do it after washing but before final curing, when the resin is less brittle), trim nubs with a flush cutter or blade, wet-sand with fine grits while wearing gloves and a mask, fill pits with a UV putty, and spray a primer surfacer to hide faint layer lines before painting.
- Time15-60 minutes per print
- DifficultyBeginner to intermediate
Safety first
- Wear nitrile gloves until the print is fully cured.
- Wet-sand and wear a dust mask: resin dust should not be breathed.
- Do not wash sanding water containing uncured resin down the drain; follow local rules.
Is this your problem?
- Nubs or pits where supports wereSupport marks: this page.
- Fine ribs on curvesLayer lines: this page (also check print settings).
- Surface tackySee Sticky resin print first.
- Cracks around support pointsSupports snapped off with force or print over-cured: cut, do not snap.
You'll see
Small raised nubs or craters on the underside or wherever supports were, and a fine ribbed texture across curved surfaces that becomes obvious after priming.
Likely causes
- Snapping or pulling supportsBreaking a support pulls a small crater out of the print.
- Thick support tipsBigger contact points leave bigger marks.
- Layer height and orientationCurves printed at a shallow angle show each step clearly.
- Fully cured brittle resinCured resin chips and cracks more when supports are removed.
What you need
- Nitrile gloves and a dust mask
- Flush cutter or sprue cutter, sharp blade
- Wet-and-dry sandpaper or sanding sponges (#400 to #2000 range)
- UV-curing putty and UV light
- Primer surfacer
How to fix it
- Wearing gloves, remove supports by cutting them close to the print with a flush cutter, rather than snapping them off.
- Trim remaining nubs flush with a sharp blade in small passes.
- Wet-sand the area: start around #400-#600 on nubs, then go finer (#800-#1500 and up). Keep the paper wet so dust stays in the water.
- Fill pits and gaps with UV putty, cure it with a UV light and sand flush.
- Spray a primer surfacer; sand lightly with a fine grit where layer lines still show, and re-prime.
- Paint once the surface is smooth under raking light.
What to avoid
- Dry-sanding resin without a mask.
- Sanding uncured or tacky prints.
- Cutting supports with fingers in front of the blade.
Common wrong fixes
- Thick coats of normal primer to hide layer lines: it softens detail; use a primer surfacer and sand.
- Sanding with coarse grit only: leaves scratches that look like layer lines.
Not worth fixing, or time to ask us
If layer lines are very strong, the fix may be in printer settings rather than finishing. Ask us about finishing tools; for printer settings, check your resin and printer maker's guidance.
By situation or hobby
Miniatures
Place supports on hidden faces where possible; tiny marks on the base side do not matter.
Gunpla and kit parts
Parts that must fit together: avoid over-sanding mating faces.
Large, smooth props
Layer lines show most: several rounds of primer surfacer and sanding.
Water-washable resin
Same finishing; dispose of rinse water as the maker advises.
Already ruined?
Chipped crater from a snapped support: fill with UV putty, cure, sand. Cracked area: stabilize with thin CA, then fill and sand.
Next time
- Cut supports, never snap.
- Use lighter support tips where your slicer allows.
- Orient visible curves to reduce stepping.
- Remove supports before final cure if your resin is brittle when cured.
Frequently asked questions
Should I remove resin supports before or after curing?
Many people remove them after washing but before final curing, when the resin is less brittle. Follow what works for your resin.
How do I remove support marks from a resin print?
Trim with a flush cutter and blade, wet-sand with fine grits, and fill pits with UV putty.
How do you hide layer lines on resin prints?
Spray a primer surfacer, sand it lightly when dry, and repeat until smooth.
Is resin dust dangerous?
Breathing resin dust should be avoided. Wet-sand and wear a dust mask.
Jargon explained
- Supports
- Thin printed struts that hold a resin print during printing.
- Layer lines
- Fine steps between printed layers.
- UV putty
- A filler that cures under UV light.
Tools that can help
-
Stedi Large-Single-Blade Sprue Cutter $37.95
Why it helps: An ultra-thin single-blade cutter for plastic and resin that cuts nearly flush.
How to use it
Cut supports close to the print instead of snapping them.
-
UV Curing Repair Putty for 3D Prints from $12.95
Why it helps: A light-curing patching clay for printer flaws that hardens in seconds under violet light.
How to use it
Press it into pits and gaps, cure, then sand.
-
Stedi Ultraviolet Light $21.99
Why it helps: A small UV torch for curing UV glues and resins; check the product details for the light wavelength.
How to use it
Check the product details to see whether it suits your putty or resin, and follow the maker's cure time.
-
Guazi Studio 100ml Model Primer Surfacer $23.95
Why it helps: A primer surfacer that lays down an even base and fills faint tool marks.
How to use it
Prime, sand lightly where lines show, and re-prime.
-
Semi/Full Face Dust Mask With Safety Glasses from $18.95
Why it helps: A full-face mask with safety glasses; check the product details for the protection it offers.
How to use it
Wear when sanding resin.
Reviewed November 3, 2026