What is frosting and why does it happen?

Frosting is a white, milky haze that appears on a miniature after spray varnishing. It's caused by the propellant trapping moisture from the air as it evaporates. High humidity is the main culprit -- above 70% is risky, above 80% is nearly guaranteed to frost. The cure is dry climates or brush-on varnish. If it happens, a coat of gloss varnish can sometimes salvage the model, followed by matte varnish once the gloss has dried.

Matte vs satin vs gloss -- which should I use?

Matte is the standard choice for most miniatures. It kills the shine from washes and gives a natural finish. Satin is good for leather, worn metal, and skin where a slight sheen is appropriate. Gloss is for gems, eyes, glass effects, and as an intermediate sealing layer before washes (gloss primer + gloss varnish before washing lets the wash flow and pool better). Most painters use matte for the final coat on the whole model, then spot-apply gloss selectively.

Can I varnish in winter or cold conditions?

Cold temperatures slow the propellant and can cause spray varnish to spatter rather than mist, leaving a grainy finish. Under 50 degrees Fahrenheit is the risk zone for most rattle cans. Warm the can in your hands for a few minutes before using, work in a warmer room if possible, or switch to brush-on varnish. Brush-on varnish is not temperature-sensitive in the same way.

Does varnish affect resin differently than cast plastic?

Not significantly, but resin miniatures benefit more from varnishing than cast plastic minis do. Resin paint adhesion, while good over a proper primer coat, is still more vulnerable to chipping than the mechanical grip paint gets on textured plastic. A varnish coat is more important on resin than on plastic, not less. Skip it on resin and you'll notice chips faster.

My varnish went on shiny even though I used matte. What happened?

Either the coat was too thick, or the varnish was applied too close to the model, or the can wasn't fully shaken. A pooled varnish coat dries shiny even from a matte can. Thin coats from further away consistently produce a matte result. If the model is already dry and shiny, a light second coat from further away and with good shaking often corrects it.

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How to Varnish and Seal 3D Printed Resin Miniatures

Resin miniatures chip without varnish -- it's not optional. Here's how to apply matte, satin, and gloss varnish without frosting, cloudiness, or ruining a paint job you spent hours on.

This guide contains affiliate links — I may earn a small commission at no extra cost to you.

There’s a category of mistake that hurts more than other painting mistakes. The miniature is done. You spent two or three sessions on it. It looks exactly the way you wanted. Then you spray varnish it and the whole thing goes white and cloudy.

That’s frosting, and it’s the main thing this guide exists to prevent.

Varnishing resin miniatures is not complicated — it’s a 10-minute step. But the ways to do it wrong are specific, and they’re worth knowing before you spray anything at a model you care about. This covers the full process: which products work on resin, matte vs satin vs gloss, when to use brush-on vs spray, and how to avoid frosting.

If you’re still in the painting process and haven’t sealed yet, the full painting guide for resin miniatures covers the complete workflow from surface prep through varnishing.

Why Varnishing Resin is Not Optional

Resin is brittle. The paint sits on top of the primer, which sits on top of the resin surface. Without varnish, the paint film is vulnerable to chipping from any contact — handling during games, storage, transport. Anywhere the paint touches something hard, the acrylic can crack and flake.

Cast metal and plastic miniatures have the same vulnerability, but resin more so. The resin surface is denser and smoother, so paint gets less mechanical grip than it does on rough-textured plastic. Primer helps significantly. Varnish is what turns a paint job that will chip within a month into one that survives years of handling.

If you paint display models that never get touched, you can skip varnish. Everything else gets sealed.

Spray vs Brush-On: Which to Use

Both work. The choice is mostly about your situation.

Spray varnish is faster, produces more even coverage on complex geometry, and is better for batch sealing multiple models at once. The downside: humidity causes frosting. If you’re in a climate where humidity is unpredictable, spray varnish will eventually betray you.

Brush-on varnish is humidity-independent, gives you total control over where the product goes, and is the safer option for models you really care about. It’s slightly slower and requires more passes for full coverage, but there’s no frosting risk.

For most hobbyists doing tabletop gaming miniatures: spray varnish in decent weather, brush-on when humidity is high or for anything you’re particularly attached to.

Products That Work

Spray:

Testors Dullcote — the industry standard for matte spray varnish. Produces a genuinely matte finish, very durable. Works on resin without issue.
Vallejo Surface Primer Matt Varnish spray — less widely available but excellent results; low frosting risk.
Citadel ‘Purity Seal’ — widely used, reliable in dry conditions, but higher frosting risk than Dullcote in any humidity.

Brush-on:

Vallejo Matte Varnish — the go-to brush-on matte. Thin it slightly with water (about 2:1 varnish to water), apply in thin passes. Dries true matte. Very reliable.
Liquitex Matte Medium — not a traditional varnish but widely used as a brush-on matte sealer. Produces a very flat, non-reflective finish.
Citadel ‘Ardcoat (gloss) — for spot-applying gloss effects to gems and eyes.

Avoid:

Hardware store polyurethane or floor varnish. They’re too thick, they yelllow over time, and they can react with acrylic paints.
Any varnish marketed for “furniture” or “wood” — same problems.

The Varnishing Process

Spray varnish

Check humidity. Above 70% relative humidity, switch to brush-on. This is not a suggestion.
Shake the can. Two full minutes. Under-mixed spray goes on unevenly.
Test on cardboard. Spray a quick burst on cardboard to make sure the can is producing a fine mist, not spattering.
Spray the model. Hold 10-12 inches away. Sweep the spray in a steady motion — don’t stop over any one area. One even pass.
Let dry 20-30 minutes.
Assess and repeat if needed. A single thin coat is enough for most models. If coverage looks uneven or patchy, apply a second thin coat after the first is fully dry.

Brush-on varnish

Thin slightly. For Vallejo Matte Varnish and similar, 2:1 (varnish to water) produces a more even coat and prevents pooling.
Apply in thin passes. Use a large, soft brush (size 4 or larger). Apply in smooth strokes over sections. You’ll see the varnish go on slightly milky — it dries clear.
Don’t overwork it. Brush-on varnish sets quickly and going back over a section that’s started to dry drags it. Apply a section and move on.
Two passes for full protection. Let the first coat dry completely (30-60 minutes) then apply a second thin coat. Two thin coats protect better than one.

Spot gloss

After the matte varnish is completely dry, apply brush-on gloss to specific elements. Gems, eyes, water effects, any surface that should read as shiny. Use a small detail brush and stay within the lines — gloss on a matte robe reads as a mistake, not an effect.

Frosting: What to Do if it Happens

Frosting looks like the model has been dusted with white powder or has a milky haze. If you catch it while the varnish is still wet, set the model aside to dry — sometimes it clears on its own in dry air.

If it’s fully dry and still white: apply a coat of gloss varnish over the frosted area. The gloss layer can sometimes dissolve and reset the frosted matte, producing a clear (if shiny) result. Once the gloss is dry, apply a careful coat of matte varnish in ideal conditions (low humidity, warm temperature) from further away than you initially sprayed.

Prevention is much easier than recovery. When in doubt, use brush-on varnish.

Varnishing for Different Use Cases

Gaming miniatures that see regular handling: Two coats of matte spray or brush-on. Prioritize coverage under the base where your fingers grab the model.

Display models: One thin matte coat is sufficient if the model lives in a cabinet. Heavier varnish slightly changes the surface texture and can dull very fine detail.

Models being based after painting: Apply varnish to the miniature before you finish the base. Then base, then apply a light final coat over everything. This seals the model, seals the basing materials, and gives the whole piece uniform protection.

Contrast or speed-painted armies: One coat of brush-on matte is faster than spray for batch sealing. Prop them on a piece of foam and do all of them in sequence.

For the full miniature painting workflow, including the basing step that comes just before varnishing, see the how to paint 3D printed resin miniatures guide.