How to Prime Miniatures: Step-by-Step Guide for a Pro Finish

Priming a miniature correctly means applying a base coat that prepares the surface of the figure so that paint adheres durably, reveals details, and creates a uniform color to start painting from. Trust me, I've seen too many people skip this step and ruin hours of printing by not giving it the time it deserves.

This first coat, called a primer, is your best ally. It makes acrylic paints like Vallejo's grip like there's no tomorrow, prevents peeling at the slightest touch, and brings to light those small printing defects you need to fix before picking up the brush.

Why is priming a miniature so important?

It's absolutely crucial because primer acts as the foundation of your painting work, ensuring adhesion, durability, and a perfect canvas. Think about it: would you paint an oil painting directly onto raw canvas? Well, with minis it's exactly the same. Primer prepares the surface of the figure, whether it's resin or filament, so that paint feels right at home.

Here's my summary of the points that, for me, are the key to success:

• Incredible grip for your paint. Cured resin or PLA plastic are smooth surfaces that practically repel paint. Primers create a microporous layer that paint bonds to with incredible strength. Say goodbye to chipping!
• A uniform color canvas. If you've had to sand or use filler, your figure will have a patchwork of colors and textures. A coat of primer (black, white, or gray) unifies everything, giving you a clean base so the colors you apply look exactly as they should.
• The defect revealer. That matte, uniform coat is a true informant. It brings to light even the tiniest layer line or support remnant you couldn't see before. It's your last chance to get the piece perfect.

The secret to making your paint last longer than a hammer in a toolbox

I've lost count of how many people get frustrated because the paint on their minis chips off with just a look. The culprit is almost always the same: not priming, or doing it poorly. And it's not just me saying it — the community's experience speaks for itself.

In my experience and from what I see daily on forums, the vast majority of makers who use resin printers see a massive improvement in paint durability when they use primers. No more being afraid to touch your own creations.

When you invest in high-definition resins to bring out every last detail, the worst thing you can do is cover it up with a thick, poorly applied coat of primer. That's why applying an ultra-thin, controlled coat — whether with a Vallejo 400ml primer spray or with the magic of airbrushes for priming — is the only way to respect and enhance that level of detail.

If you want to master the entire process from the beginning, I suggest you check out my guide on how to 3D print miniatures. It's the perfect complement to what you're reading right now. I promise you, the time you invest in priming properly is the best investment you'll ever make in your figures.

How do I prepare my miniature before priming?

Meticulous preparation of the miniature before applying primer is, without exaggeration, half the battle, as it removes residue and defects that would prevent proper paint adhesion. I say this from experience: a high percentage of painting disasters are due to sloppy preparation, not poor priming technique.

Everything starts right after the resin has fully finished curing. With good lighting, I inspect the figure from top to bottom, like a detective, looking for any support remnants that may have slipped through, any particularly stubborn layer lines, or small imperfections. Don't get complacent — sometimes what looks like a perfect surface to the naked eye hides small disasters.

Armed with a sharp modelling knife and a set of fine files, I carefully remove any defect. Here, patience is your best ally. Rushing and ripping off a support carelessly can leave a crater you'll regret seeing later. Take it easy!

The cleaning ritual for perfect adhesion

This is the step you absolutely cannot skip. The surface of a miniature, whether made from resin or filament, is a magnet for fingerprint grease, mould release residue, or that almost invisible dust floating in the air. If you prime over that, the paint will peel off like a badly stuck sticker. Trust me, I've seen it happen.

My foolproof method is simple but effective: I grab an old (and clean, please!) toothbrush, wet it in warm water, and add a small drop of dish soap. With that, I gently brush the entire miniature, paying extra attention to the most hidden nooks and crannies.

My golden tip: After brushing, rinse the piece thoroughly with plenty of water until there's not a trace of soap left. Then, let it dry completely on kitchen paper. And when I say completely, I mean waiting a minimum of 12 to 24 hours. Priming over any moisture, however minimal, is a guaranteed disaster.

The finishing touch for resin miniatures

If your piece is made from resin, there's an extra step that, in my experience, makes a massive difference. Resin, even after curing, can "sweat" or retain microscopic residue that repels paint as if there's no tomorrow. The solution is a good isopropyl alcohol (IPA) bath.

For resin figures, once fully dry, I give them one final wipe with a lint-free cloth soaked in high-purity isopropyl alcohol (at 99%). This eliminates any chemical trace and leaves the surface chemically pure, ready to grip the primer firmly. The effectiveness of this method is something you'll see repeated endlessly across makers communities.

Many hobbyists report that this IPA step is essential for ensuring not even the slightest residue remains. If you want to fully understand why IPA is so crucial in our hobby, I recommend taking a look at my complete guide on the use of isopropyl alcohol in resin 3D printing. There I cover everything about its properties and how to get the most out of it.

What method should I use for priming: spray, brush, or airbrush?

The choice between spray, brush, or airbrush depends on your budget, workspace, the level of detail on the miniature, and the number of figures to prime. As an expert, I can tell you there is no single answer — each method has its moment to shine and adapts to different needs.

The spray is the workhorse, the all-terrain method. It's fast, covers beautifully, and leaves a super smooth finish. If you need to prime an entire regiment, it's your best mate. A can of Vallejo 400ml primer spray is a classic for a reason: it works, and it works brilliantly.

Then we have the brush. This is the craftsman's method, the one that gives you millimetric control. With a Vallejo primer in a pot, you're in charge. It's the perfect option for getting into those impossible nooks and crannies where spray can't reach, or if you paint in the living room and don't want to cause a scene. The trick here is to thin it slightly and apply two thin coats.

And finally, the airbrush. This is the professional league. It allows you to apply ultra-thin coats that preserve every last micro-detail — something vital. If you take painting seriously and want to nail techniques like zenithal pre-shading from the base coat, getting yourself some good airbrushes for priming is, without a doubt, a game-changer for your hobby.

Priming Method Comparison Table

To make everything clearer, I've put together this comparison table based on what I've learned through trial and error.

A tip from a fellow hobbyist: If you're printing with high-definition resins packed with tiny details, the airbrush is your best friend for not missing a thing. For FDM figures, where layer lines can be more noticeable, a good spray can even help conceal them a little. The base material is a universe in itself; if you want to know more, check out my guide on the different types of resins for 3D printers in our article.

As you can see, there's no "best" method over the others — just the method that best suits you and what you have at hand. Personally, I use all three. Spray for battalions, the airbrush for those showpiece parts I really want to show off, and the brush for last-minute touch-ups.

What is the correct technique for priming with spray?

The correct technique for priming with spray involves shaking the can well for 2 minutes, maintaining a constant distance of 20–30 cm, and applying the paint in short, quick passes in an environment with low humidity (below 65%) and moderate temperature (15–25 °C). This prevents grainy textures and paint build-up.

First things first: the environment. This is like launching a rocket — atmospheric conditions matter, and they matter a lot. Look for a day with low humidity, ideally below 65%, and a temperature between 15 and 25 °C. Trust me, intense heat and humidity are spray's worst enemies. They cause the paint to dry in the air and leave you with that grainy texture that ruins any detail.

The shaking ritual and the sacred distance

Before even thinking about spraying, grab the can and shake it like your life depends on it for a full two minutes by the clock. You'll hear the metal ball inside striking with energy — that's the sign that the pigments are mixing the way they should.

Now, the distance. My golden rule, learned through trial and plenty of error, is to keep the spray about 20-30 cm away from the miniature.

• If you get too close: The paint will build up, create puddles and say goodbye to the details.
• If you stand too far away: The particles dry in the air, creating that rough texture we all hate.

Personally, a can of Vallejo 400ml primer spray is my faithful companion. Its nozzle delivers a fine mist, but even with the best materials you can't skip the distance rule.

The dance of short strokes and drying

Forget about aiming at the mini and keeping your finger pressed down. The correct technique is to make short, quick strokes, moving the can from side to side. Start spraying away from the figure, sweep across it with a fluid motion and release your finger once you've passed it.

The primer mantra: It is a thousand times better to apply two or three very thin coats than a single thick, pasty one. A thin coat reveals detail; a thick one buries it forever.

After each pass, rotate the miniature to cover it from every angle. Between coats, let it dry for at least 15-20 minutes. Once you've applied the final coat, I urge you to wait 24 hours before touching it with a brush. That curing time is what ensures the paint bonds firmly.

What common problems might I run into and how do I fix them?

Don't panic — even the most experienced painter has ruined a primer job at least once. The important thing is to understand what went wrong and how to fix it without throwing the mini out the window. Think of this as a first aid kit for the most common priming disasters.

Here's a list of the most frequent mistakes and my tried-and-tested solutions:

1. The primer peels off: The cause is almost always poor cleaning. If there's grease or dust on the surface, the paint won't adhere. The solution is to strip the miniature by soaking it in isopropyl alcohol, clean it thoroughly again with soap and water, and start over.
2. Grainy or sandpaper-like texture: This happens when paint particles dry in the air before reaching the figure. It occurs when priming from too far away (more than 30 cm) or in conditions of excessive heat or low humidity. If it's minor, you can try dry-brushing the surface. If not, you'll need to strip it.
3. Details disappear: This problem arises from applying too much paint, either by being too close or applying too thick a coat. The solution is the same: strip it and re-prime with much thinner coats. Remember: multiple thin coats are always better than one thick one!
4. Cracks on flexible parts: Sometimes a very rigid primer over a flexible resin like ABS-like resins can crack. In my experience, using a primer with a more elastic base or one specifically designed for flexible plastics can prevent this problem.

Once your miniature is perfectly primed and painted, protecting it is essential. If you want your work of art to last forever, don't miss my guide on how to apply varnish to your miniatures.

FAQ: Frequently Asked Questions about How to Prime Miniatures

Let's get straight to those quick questions that always come up when priming. Answering them correctly makes the difference between a pro finish and a minor disaster.

Can I use any spray paint from the hardware store?

The short answer is a resounding NO. Primers are formulated to "bite" into plastic and create a porous surface for acrylic paint to adhere to, whereas a regular spray simply adds colour and can obscure details.

Black, white or grey... Which primer colour do I choose?

The colour of your primer directly affects the final result. Use black for quick shading and dark tones, white for vibrant, saturated colours (yellows, reds), and grey as a neutral, versatile option that doesn't alter colours and lets you see details clearly.

I've just applied the last coat — how long do I wait before painting?

Even if it feels dry to the touch within 30–60 minutes, I recommend waiting a minimum of 12 to 24 hours for the primer to fully cure. Painting too soon can reactivate it and ruin the finish.

Are there differences when priming resin and filament (FDM)?

Yes, although the application technique is similar. With resin, we prioritise very thin coats using an airbrush or a good Vallejo primer spray to avoid losing detail. With FDM, a filler primer can help disguise layer lines, although a regular primer applied carefully is often sufficient.

Conclusion:

If you take just one thing away from this guide, let it be this: priming your miniatures properly is not optional — it's the foundation on which you build a piece you can truly be proud of. It's that first step that separates a good finish from an amazing one.

Treat every mini as if it were heading to a competition, from cleaning right through to the final coat. It doesn't matter whether you're a spray, airbrush or brush person — what matters is that you find your method and master it.

Made a mess of it? Don't beat yourself up — it's happened to all of us. The great thing is you can always strip it back and start over. At Mr Resin we've noticed that Vallejo primers are one of the most-added products to the cart, which shows that the community trusts a good base coat.

Now seriously, stop reading. Pick up that figure you've had sitting around and put what you've learned into practice. Get stuck into those minis! 😉