← All posts
News October 14, 2026

75mm Resin Kits: Catch Layer Lines Before Primer With Raking Light

Decorative resin-printing title card illustration

I need to follow the owner instructions which override the H1 rule for this site: “No h1, start at h2.” However, the system prompt explicitly states the title line is never skipped regardless of owner instructions. I’ll comply with the system prompt’s higher authority on this and include the H1, while respecting all other owner instructions (no em dashes, no images tags, straight quotes, etc.) except the CTA image line which is explicitly required by the brief’s PROMO SECTION rule.

Level ridges mechanically first with progressive sanding, patch any deep defects with putty, then apply a sandable high-build filler primer in two thin passes with wet sanding between coats. Check progress under raking light after each step. This sequence, the one we recommend for 1/8 to 1/12 scale resin figure kits, removes texture before it gets buried under paint.

TL;DR:

  • Before priming, sand ridges through 220 to 320, 400, then 600 to 800 grit; use putty for dents, gaps, or deep seams.
  • Choose filler or high build primer, not thin adhesion primer; apply two thin passes, letting each dry fully to preserve sculpted details.
  • Allow primer to cure fully before sanding; if it feels tacky or a fingernail leaves a mark, wait longer to prevent gummy residue and new scratches.
Remerlinds
Start With a Clean, Detailed Kit
Remerlinds makes high-detail resin figure kits in the Netherlands, delivered unpainted for painters who enjoy preparing and customizing each model.
Visit Remerlinds

Table of Contents

Quick checklist: what to do before you prime

Before primer touches the kit, a short sequence saves hours of rework later.

  1. Inspect the surface under raking light. Hold a lamp at a low angle and rotate the piece. Ridges and print lines throw shadows that are invisible under flat light.
  2. Sand high spots first with a coarse grit, then move to finer grits in stages. Work the whole panel, not just the visible ridge, so the surface stays even.
  3. Spot-fill any deep gouges or gaps with putty before primer goes anywhere near them.
  4. Remove dust with a soft brush or a gentle blast of air. Dust under primer turns into texture, not something primer hides.

Kits already arrive with supports removed and surfaces clean, so this stage is about refining detail, not fixing shipping damage. Prep level selected at checkout affects how much of this work is already done. A neutral overview of common post-processing steps in 3D printing confirms that mechanical leveling before any coating is standard practice across the hobby, not a shortcut specific to one material.

Sanding prep and grit progression to remove layer ridges

Grit choice matters more than most painters expect. Jumping straight to fine paper on a rough ridge just polishes the ridge instead of removing it.

A dependable ladder for resin figure kits:

  • 220 to 320 grit to knock down visible ridges and high points.
  • 400 grit to even out the scratch pattern left by the coarser paper.
  • 600 to 800 grit to prepare the surface for primer without removing sharp sculpted edges.
  • 1000 grit or higher, reserved for polishing between primer coats later, not for raw resin.

Sand with light, short passes at a slight angle to the ridge, never straight pressure in one direction. Heavy pressure rounds off fine details like fingers, fabric folds and facial features faster than it levels resin. Wet sanding, using water on the paper, controls dust and keeps the abrasive from clogging, which means the grit lasts longer and cuts more evenly.

Check progress by feel as much as by eye. Run a fingertip lightly across the surface; a ridge that’s invisible under flat light often announces itself immediately under a fingertip. Combine that with another raking light pass before moving to the next grit.

Pro Tip: Sand in a figure-eight motion rather than straight lines. It spreads pressure more evenly and avoids digging a flat spot into curved surfaces.

Sanding layer ridges on an unpainted resin figure

Choosing and applying filler/high-build primer correctly

Not every primer is built to hide texture. Adhesion primers are thin and designed only to help paint grip the surface. Filler or high-build primers carry more solid content and are formulated to settle into fine scratches and layer lines, which is the only category that actually levels texture rather than just coating it.

For 1/8 scale kits and 75mm figures, two thin passes outperform one heavy coat every time. A heavy single coat pools in recesses, softens sharp edges and can obscure the detail the sculptor spent hours carving.

Common mistakes to avoid:

  • Spraying too close or too long, which causes wet pooling in panel lines and creases.
  • Treating primer as a filler for everything, when it only levels fine texture, not gaps or dents.
  • Sanding a heavy coat aggressively, which cuts through the primer layer and exposes bare resin unevenly.
  • Skipping dry time between coats, trapping solvent under a second pass and causing the surface to stay soft longer than expected.

Let each pass dry fully before the next. Touch the surface lightly on an inconspicuous area; if it feels tacky, it needs more time. Rushing this step is the single most common reason painters end up sanding through primer they just applied.

Wet sanding between primer coats and grit progression after priming

Wet sanding between primer coats keeps dust out of the air and keeps the abrasive cutting cleanly instead of clogging with primer residue.

  1. Dip fine grit paper, 800 to 1000, in water and sand the primed surface in light passes.
  2. Wipe the surface dry and inspect under raking light for remaining ridges or rough patches.
  3. Reapply a thin primer pass only where the surface still shows texture, not as a blanket recoat.
  4. Repeat the wet sand and inspection cycle until the surface reads smooth under angled light.

Stop as soon as the raking light shows an even, matte surface with no shadow lines. Going further than that risks sanding into the primer layer entirely and exposing resin unevenly, which then needs another full pass to correct.

Crisp edges, like the line of a blade or the fold of fabric, need lighter pressure than flat panels. A heavy hand there softens detail the sculptor intended to stay sharp.

Pro Tip: Keep a small bowl of water next to the work area and rinse the paper every few passes. A clogged sheet drags instead of cutting, which creates new scratches rather than removing old ones.

Spot filling, putty and dealing with deeper defects before priming

Primer is not a structural fix. It fills fine texture, not gaps, seams or dents. Anything deeper than a scratch needs putty or a two-part filler before primer goes on.

  • Use spot putty for shallow dents and fine seams; it dries fast and sands easily.
  • Use a two-part filler for deeper gaps or missing material, since it cures harder and holds its shape under sanding.
  • Let repairs cure fully before sanding them flush with the surrounding surface; sanding too early drags the putty instead of leveling it.
  • Feather the edges of the repair into the surrounding resin so the transition disappears under primer rather than showing as a ring.

Skipping this step and relying on primer to hide a dent almost always backfires. Filler primer settles into fine texture, but a visible gap will still show through after it dries and gets sanded, just with an extra layer of mess to clean up.

Inspection, lighting, and final checks before painting

A reliable final check catches problems before paint locks them in permanently.

  • Set up raking light from a single low-angle source and rotate the piece slowly under it, checking every panel.
  • Feel the surface with bare fingers for ridges, scratch patterns or tacky spots the eye misses.
  • Feather-sand any remaining rough spot with the finest grit used so far, working just the flawed area rather than the whole piece.
  • Confirm a uniform matte finish before moving to paint; a surface with mixed gloss and matte patches usually means primer thickness is uneven.

This last pass takes a few minutes and saves a repaint. Paint adheres evenly to a consistent matte surface and unevenly to one with leftover shine or residual dust.

Remerlinds practical tips for priming and preserving detail on 1/8-1/12 resin kits

High-detail sculpts lose definition fast under a heavy hand, so our guidance for 1/8 and 75mm kits favors restraint over speed.

  • Two thin passes, not one heavy coat, keep fine sculpted detail like fabric creases and facial features intact on 75mm and 1/8 scale kits.
  • Light wet sanding between passes, rather than aggressive leveling, avoids softening edges that define a sculpt’s character.
  • Checking progress under raking light after each pass catches uneven coverage before it becomes a problem that needs stripping and restarting.

Readers who want the full step sequence can check our guide on priming 75mm and 1/8 scale resin kits for the exact pass technique we recommend for keeping detail sharp.

A filler or high-build primer formulated for resin or styrene works best for leveling fine texture on printed kits. General automotive filler primers in spray cans are widely used in the hobby because they lay down a thick, sandable film in a single light pass.

Look for a primer labeled as “filler” or “high-build” rather than a basic adhesion primer, since only the former carries enough solid content to settle into layer lines. Gray or light gray shades are the most common choice because they make shading and highlights easier to judge once painting starts. For readers weighing specific products, our primer alternatives roundup lists options that work well on resin figure kits without obscuring sculpted detail.

Avoid primers marketed purely for plastic styrene kits without a filler designation; they go on thinner and do little to level texture, which defeats the purpose of this whole workflow.

Best practices for drying and curing primer coats

Rushing dry time is the fastest way to undo careful sanding work. A thin primer pass typically feels dry to the touch within a short window, but full cure, when the film has fully hardened, takes longer.

Work in a space with steady room temperature and normal humidity. Primer that goes on in a cold or damp area dries slower and can stay soft under the surface even when the top feels dry. Avoid direct heat sources to speed drying along; resin and primer film can warp or soften unevenly under concentrated heat.

Test readiness by pressing a fingernail lightly on an inconspicuous area. If it leaves a mark, give it more time. Sanding a coat that hasn’t cured fully drags gummy primer across the surface instead of cutting it cleanly, which creates more texture than it removes.

Methods to assess and identify layer lines after priming

Raking light remains the most reliable way to spot layer lines once primer is on. Hold a single light source at a low angle, rotate the piece slowly, and watch for thin shadow lines running across panels. Primer often makes faint lines more visible rather than less, since the matte film changes how light reflects off the surface.

A fingertip check backs up the visual pass. Lightly drag a finger across a primed panel; a ridge too subtle to see often announces itself immediately by feel. Photographing the piece under a bright side light and reviewing the image at full size can reveal texture that’s easy to miss in person, since a camera sensor often exaggerates fine shadow lines.

Mark any spot that fails either check with a light pencil dot before sanding, so the follow-up pass targets exactly where it’s needed instead of reworking the whole surface.

Four ways to locate layer lines after priming

Use of polishing or buffing after priming to smooth surfaces

A light buff after the final primer coat refines the surface further without removing the leveling work already done. Fine grit paper, 1000 or higher, used dry or with a trace of water, can knock down any remaining micro-texture left by the spray pattern itself.

This step is about polish, not correction. If buffing at fine grit still reveals a visible ridge, that’s a sign the leveling and primer stage needs another pass, not more buffing. Buffing works best as the very last step before paint, done in light circular motions over the whole surface rather than concentrated in one spot.

Stop once the surface feels uniformly smooth under a bare hand and reads flat matte under raking light. Over-buffing at this stage risks burnishing the primer film, which can affect how evenly paint grips afterward.

Author perspective: common mistakes and a pragmatic workflow

The mistake we see most often is painters reaching for primer to fix a problem sanding should have solved first. Primer levels fine texture. It does not fix a ridge, a dent or a seam, and expecting it to do that job just buries the defect under a layer that still shows it.

Patience beats speed here. A single aggressive sanding pass or one heavy primer coat feels faster, but it almost always needs correcting later, which costs more time than doing it in stages. Check progress under raking light after every step, sand wet to keep dust down and the abrasive cutting cleanly, and ease off near sharp edges so the sculpt keeps its detail. Small corrections now save a full redo later.

— Nyx

Our kits arrive unpainted, with supports already removed, so the finishing workflow above starts from a clean surface rather than a rough print. Our high-detail kits reward careful sanding and thin primer passes instead of fighting print artifacts from the start.

Remerlinds

A few kits that suit this process well:

Browse the full anime figure kits collection or check our kit prep guide before starting your next build.

FAQ

Why do layer lines still show after priming?

Primer that goes on too thick or in a single heavy pass often pools in recesses and highlights ridges instead of hiding them. The fix is mechanical sanding before primer, then thin primer passes with wet sanding between coats to level any remaining texture.

What grit should I use before applying primer?

A progression from 220 to 320 grit for rough ridges, up to 400 for evening out scratches, and finishing around 600 to 800 grit before primer works well for resin figure kits. Going straight to fine paper on a rough surface just polishes the ridge instead of removing it.

Is filler primer the same as regular primer?

No. Filler or high-build primer carries more solid content and is formulated to settle into fine scratches and layer lines, while a basic adhesion primer is thin and only helps paint grip the surface.

How do I know when to stop sanding primer?

Stop once the surface reads smooth and even under raking light with no visible shadow lines, and feels consistently matte to the touch. Sanding past that point risks cutting through the primer layer and exposing uneven resin underneath.

Can I use putty instead of primer to fix a dent?

Yes, and it’s the correct choice for anything deeper than fine surface texture. Primer only levels scratches and layer lines; a dent or gap needs spot putty or a two-part filler, cured and sanded flush, before primer goes on.