The Short Version
If you keep opening fresh paint pots to find thick, clumpy, or fully dried paint, it's tempting to assume you're doing something wrong. In most cases, you're not. The real culprit is usually the paint itself, specifically how thin the formula is and how well the pots actually seal. A few drops of water can fix a single dried pot. Choosing a better kit fixes the problem permanently.
If you've opened a brand new paint by numbers kit only to find one of the pots already gone thick, or come back to a half-finished canvas after a week away to discover three colours have turned into hard little pucks, you've probably already searched for the fix. Add water, stir with a toothpick, wait. It works, and we've written about it ourselves.
But here's the question almost nobody answers: why does this keep happening in the first place? Some painters go through an entire 48-colour kit without losing a single pot to drying. Others lose two or three before they've even started. That difference isn't luck, and it isn't about how careful you are with the lid. It comes down to what's actually in the pot.
A single drop of water fixes a thick pot. The right kit means you rarely need to.
Why Does Paint By Numbers Paint Dry Out So Fast?
Acrylic paint dries through evaporation. The pigment in your paint pot is suspended in a water-based polymer binder, and the moment that pot is opened, even briefly, water starts leaving the mixture. As the water evaporates, the polymer particles crowd together and eventually fuse into a solid film. That's the same process that lets acrylic paint dry permanently on your canvas; it just happens inside the pot instead, which is the last place you want it.
Every acrylic paint behaves this way to some degree. But not every paint behaves this way at the same rate, and that's where the real difference between a good kit and a frustrating one shows up.
Thin, watery formulas dry faster
A paint with less pigment and more water by volume has more liquid to lose before it reaches a usable consistency. Cheaper kits often cut costs by using thinner, more diluted paint, which means less margin before it tips over into thick or clumpy.
Poorly designed pots and lids
Even a single hairline gap in a lid lets air slowly in. Cheap pots often use thin plastic that warps slightly with handling, or lids that don't fully click shut, both of which create exactly the kind of leak that dries paint out over days or weeks, even if you think you've sealed it properly.
Some colours dry faster than others, regardless of kit quality
Whites and light earth tones generally have a higher clay or filler content than rich blues and reds, which causes them to thicken slightly faster even in a well-made kit. This is normal and not a sign of a bad product on its own, but it does mean your white pot deserves the most careful sealing every single time.
Storage conditions speed everything up
Heat and direct sunlight accelerate evaporation dramatically. A kit left near a window, on top of a radiator, or in a warm car will dry out far faster than one stored in a cool, dark drawer, no matter how good the paint itself is.
The honest takeaway here is that storage habits matter, but they're only half the story. If you're sealing your pots properly, storing them sensibly, and still losing colours every single kit, the paint formula and pot quality are very likely the actual problem, not you.
Quick Fix vs the Real Fix: What Actually Works
If you've got a pot in front of you right now, here's the honest, no-fluff version of what to do, broken down by how far gone it actually is.
| Paint Condition | What It Looks Like | What To Do |
|---|---|---|
| Slightly thick | Still spreads, but drags on the brush | Add one drop of water, stir with a toothpick for 60 seconds |
| Clumpy | Soft pieces mixed with firmer chunks | Add two to three drops, mix, then let it sit sealed for an hour before mixing again |
| Fully dried, soft puck | Solid but not rock hard | Break into pieces, add three drops, seal overnight, and mix vigorously in the morning |
| Hard, rubbery, or cracked | Will not break apart with a toothpick | Cannot be saved. You'll need a replacement pot or to mix the colour from others in the kit |
This works, and if it's the only problem you're dealing with, our full guide on reviving thick, dry, and clumpy paint walks through every stage in more detail with exact drop counts.
But here's the part that table doesn't tell you: if you're doing this every single kit, on multiple colours, the fix isn't a better toothpick technique. It's a better kit.
Tired of Losing Colours Before You Even Start?
The Real Fix Is Choosing a Kit That Doesn't Dry Out in the First Place
Properly formulated acrylic paint and pots that actually seal shut mean you spend your time painting, not reviving.
Browse Quality KitsWhat Separates a Kit That Dries Out From One That Doesn't
Once you've fixed the pot in front of you, it's worth asking the bigger question: how do you avoid this happening again with your next kit? Quality is not always obvious from a product photo, but there are a few real, checkable signs.
| What to Check | Sign of a Good Kit | Sign of a Kit That'll Dry Out Fast |
|---|---|---|
| Paint consistency on arrival | Smooth, creamy, like yogurt straight out of the pot | Already slightly thick or watery before you've even opened most pots |
| Pot and lid design | Firm click-seal lid, thick-walled pot that doesn't flex | Thin, flexible plastic, loose-fitting lid with no audible seal |
| Pigment opacity | Covers in one or two coats without thinning quickly | Translucent, watery coverage that suggests a diluted formula |
| Reviews mentioning paint quality | Verified reviews specifically mention paint thickness or coverage | Reviews focus only on the image, never mention how the paint itself performed |
| Replacement policy | The seller will replace a genuinely faulty dried pot | No clear policy or support that's slow or unresponsive about it |
This is the same checklist we cover in more depth in our guide to whether paint by numbers is actually worth it, and it's worth reading if you've had a rough experience with a previous kit and are wondering whether to try again.
Why We Build Our Kits to Avoid This Problem
I'll be straightforward about this, because it's the actual reason this article exists. Every kit we sell uses a properly formulated acrylic paint, thick enough on arrival that you genuinely shouldn't need to thin it before your first stroke, and pots with a lid that gives a real, audible click when sealed. That's not marketing language, it's a specification we hold every batch to, because dried paint is one of the most common reasons people abandon a kit halfway through, and it has nothing to do with their painting ability.
If you've had a frustrating experience with dried paint in the past, whether it was one of ours or somewhere else, it's worth giving the hobby another shot with a kit built to avoid the problem rather than one that just hopes you won't notice. A 40×50 cm kit with 24 colours is a forgiving place to start again.
Frequently Asked Questions
Why is my paint by numbers paint too thick straight out of the box?
This usually means the paint formula itself sits closer to the thick end of the acceptable range, or that the pot was sealed imperfectly during packaging, allowing a small amount of evaporation before it even reached you. A drop of water fixes it for that session, but if multiple pots in the same kit arrive too thick, that's a sign of an inconsistent batch worth raising with the seller.
What's the best flow aid for paint by numbers?
Any acrylic flow aid or flow improver made for craft or fine art acrylics works well. It loosens the paint's consistency without diluting the pigment, the way water can if overused. A drop or two mixed into your water cup, then a light dip of the brush, is usually enough.
How do I thin paint by numbers paint without ruining the colour?
Add water one drop at a time, mixing thoroughly between each drop, rather than adding several drops at once. Acrylic paint loses pigment strength and coverage quickly once over-diluted, and you can't easily reverse it once it's mixed in. If you've gone too thin, the best fix is letting the pot sit open for a few minutes to let some moisture evaporate back out.
Can I get a replacement for paint by numbers paint that dried up?
Most reputable sellers will replace a pot that arrived already dried or that failed unusually early due to a manufacturing fault, particularly if it happens across multiple colours in the same kit. It's worth checking the seller's policy before you buy, since this varies a lot between brands.
Why do white and light colours dry out faster than other colours?
White and light pastel paints typically contain more filler or clay-based pigment than richer, more saturated colours. That slightly different composition tends to thicken a bit faster, which is why it's worth sealing your white and light pots especially carefully between sessions.
Is it normal for one or two colours to dry out in every kit?
Losing the occasional pot, especially a light colour, isn't unusual even with a good kit, and a drop of water typically solves it. Losing several colours per kit, or finding paint already thick straight out of the box, points to a quality issue with the paint formula or pot seal rather than anything you're doing wrong.
Stop Losing Colours Before You've Even Started Painting
Every kit we sell uses properly formulated paint and pots built to actually seal shut. Spend your time painting, not reviving. All orders over $75 CAD ship free across Canada.
Browse Adult Kits Create a Custom Kit