How to Seal Miniatures After Painting

Why two coats, in that order

Gloss varnish is the tough one. The resin in a gloss clear cures into a hard, continuous film, which is what actually protects the paint from handling, dice bags and transport.

Matte varnish is gloss varnish with a matting agent — fine particles suspended in it that scatter light. Those particles interrupt the film, so a pure matte coat is slightly softer and slightly less protective than a gloss one of the same thickness. Pile on enough matte varnish to get a fully flat finish in one go and you also get a dusty, slightly chalky surface that dulls the colours underneath.

Gloss first, matte second gives you both: the hard protective film underneath, a thin matting layer on top. It is also the sequence that makes decals disappear, which is why it is the standard order on a painted kit.

Frosting: the failure that ruins finished models

Frosting is a white, chalky bloom over the whole model. It happens when a lacquer clear is sprayed in high humidity: the solvent evaporates so fast that it chills the surface below the dew point, moisture condenses into the drying film, and the cured varnish traps a haze of microscopic water marks.

The rule is simple and worth obeying absolutely: do not spray lacquer clear above roughly 65% relative humidity. A cheap hygrometer removes the guesswork, and a phone weather app is good enough if you are spraying outdoors. Cold is the other half of the problem — below about 10 °C the varnish goes on thick and stays soft.

If a model does frost, do not panic and do not sand it. A second light coat sprayed in good conditions redissolves the surface and often clears it completely. The same effect and the same fix on Gunpla topcoats are covered in matte vs satin vs gloss topcoat.

When to brush instead

Water-based brush-on varnish cannot frost, because there is no fast-evaporating solvent chilling the surface. If you live somewhere humid, have no outdoor space, or are sealing a single model in January, it is the right call.

The trade-offs: brush marks if applied thickly, the risk of pooling in recesses, and a finish that is slightly less uniformly flat than a good spray. Apply it thin, work in one direction, and do not go back over an area that has started to tack up. Two thin coats beat one thick one, exactly as with spray.

A brush-on satin followed by a brush-on matte is the full belt-and-braces version and it works, it just takes longer. Options and the trade-offs are ranked in the matte topcoat picks.

The four mistakes that account for most ruined models

Not shaking the can. Matting agent sits at the bottom. An under-shaken can sprays glossy, then spits settled agent as a visible speckle.

Spraying too close. Under about 20 cm the varnish arrives wet, pools in recesses and runs. Distance plus short passes is the whole technique.

Spraying in the wrong weather. See above. It is the one mistake with no recovery during the spray itself.

Handling too early. Twenty-four hours. A model that feels dry after ten minutes will still take a fingerprint at hour two.

Special cases

Metallics. Matte varnish dulls metallics noticeably — that is what it is designed to do. Seal the model matte, then go back and re-highlight the metal areas, or brush a tiny amount of gloss varnish onto the metallics afterwards to bring the shine back.

Eyes, gems and lenses. Same treatment: a dot of gloss varnish after the matte coat restores the wet look that makes them read as glass.

Bases. Seal them with everything else. It stops static grass shedding and texture paint chipping at the rim — see the basing materials.

Gaming models. Consider two gloss coats before the matte. They get handled constantly, and the extra hard layer is worth the five minutes.

Display models. One gloss, one matte is plenty, and keeping the coat thin preserves the finest edge highlights.

Still not sure you need to?

Most painters should seal most models, and the argument for and against — including the cases where leaving a display piece unsealed is defensible — is laid out in do you need to seal miniatures. If the model is going anywhere in a bag or a case, the answer is yes, and storing and transporting miniatures covers what happens next.

The three varnish chemistries

Acrylic (water-based). Brush-on or airbrush, no strong solvent, cannot frost, safe over anything. Slightly softer film and a slightly less flat matte than a lacquer, and it can go milky if applied too thickly in one pass.

Lacquer. The aerosol clears most modelers use. The hardest, flattest finish available and the thinnest coat, at the cost of strong fumes, a mandatory ventilation requirement, and the humidity sensitivity described above. Lacquer is also the aggressive one chemically — test it over enamel or unsealed decals before committing.

Polyurethane. Tough, slightly flexible, popular for gaming models that get handled constantly. Often sold as a brush-on, frequently with a slight amber tint that is invisible on most schemes and noticeable over white.

You do not need all three. One aerosol lacquer and one brush-on acrylic covers every situation: the aerosol for good weather and batches, the brush for January, for a single model, and for the gloss touch-ups on eyes and metallics afterwards.