Last updated: August 23, 2026
There are two Vallejo bottles that everybody eventually owns and almost everybody initially confuses. One says Airbrush Thinner and carries the number 71.161. The other says Airbrush Flow Improver and carries 71.462. They look alike, they sit next to each other on the shelf, and they do genuinely different jobs.
Getting the distinction right is the difference between fixing a problem and making it worse. Adding flow improver to paint that is simply too thick will not make it spray, and thinning paint that is already the right consistency will not stop it drying on your needle.
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Quick Answer
Do you need Vallejo Airbrush Thinner, or the Flow Improver?
- 71.161 Airbrush Thinner: buy this first. It adjusts consistency so the paint atomizes.
- 71.462 Flow Improver: buy it second, when paint keeps crusting on the needle tip.
- They are not substitutes. Flow improver is an additive, not a diluent.
- Neither is a cleaner. 71.099 Airbrush Cleaner is a separate bottle and does not belong in your mix.
Bottom line: thinner solves thickness, flow improver solves tip dry, and most painters end up with both.
What 71.161 Actually Does
Vallejo describes the Airbrush Thinner as extending the colors, increasing fluidity and delaying drying time, while not altering the properties of the paint. In practice it dilutes without loss of adhesion, resistance or consistency, which is the technical way of saying it thins the paint without wrecking the film.
That last part is the reason to buy it rather than reaching for the tap. Water reduces viscosity by diluting everything, binder included, and past a certain point you have a colored wash that will not stay on the model. Thinner replaces carrier and leaves the paint able to do its job.
How Much to Use
Start at roughly four or five drops of paint to one drop of thinner for a Model Air or Game Air color, and closer to two to one for a thick brush paint like Model Color. Then adjust by eye until the mix runs off the stirrer in a thin unbroken stream rather than dropping off in blobs.
Dropper bottles make this easy, which is a large part of why the Vallejo system suits beginners. Counting drops turns a vague instruction into a repeatable one, and after a few sessions you will stop counting because you can see it. Our guide to thinning acrylic paint covers the judgment call in detail.
The Flow Improver Is a Different Tool
Vallejo describes 71.462 Flow Improver as a water based product that ensures uninterrupted spraying by reducing tip drying and enhancing the flow of its airbrush paints. It works on surface tension and on how quickly the film sets at the tip, not on how thick the paint is in the cup.
So the diagnosis matters. Paint that spatters and sits grainy on the model is too thick and needs thinner. Paint that sprays fine for two minutes and then starts sputtering while a crust builds on the needle is drying at the tip and needs flow improver, a wipe, and probably a slightly wetter mix.
Do Not Overdo It
Flow improver added generously does not make the paint flow twice as well. It makes the film slower to set, which shows up as coats that stay tacky, marks that show under masking tape, and colors that move when you spray the next layer. A small proportion is the point.
The Third Bottle: Airbrush Cleaner
Vallejo positions 71.099 Airbrush Cleaner as a cleaner for use between colors that removes remaining paint and lubricates the mechanism without damaging it. It is designed to break paint down, which is precisely why it must not end up in your mix as a substitute thinner.
Every so often someone reaches for the wrong clear bottle mid session and cannot work out why the coat will not adhere. Keep the cleaner near the cleaning pot and the thinner near the mixing well. Our guide to airbrush cleaner compares this bottle with the other common options.
Which Bottle for Which Symptom
Read the problem, then pick the bottle. This is the whole reason to own more than one of them.
| Symptom | Reach for | Why | Do not |
|---|---|---|---|
| Spatter, grainy coat | 71.161 Thinner | Paint is too viscous to atomize | Add flow improver instead |
| Crust on the needle tip | 71.462 Flow Improver | Paint is setting at the tip | Keep raising the pressure |
| Color change between coats | 71.099 Cleaner | Residue from the previous color | Pour cleaner into the mix |
| Coat still tacky later | Less flow improver | Too much additive slows setting | Add more thinner to compensate |
Why This Bottle Turns Up in Every Kit
Two reasons, and neither is marketing. It is genuinely the most useful single accessory for a new airbrush painter, because thinning is the skill that decides early results. And Vallejo has the widest hobby distribution of any of the paint auxiliaries, so it is the bottle a retailer can reliably stock.
That ubiquity is also its practical advantage over slightly cheaper alternatives. When something goes wrong and you ask for help, everyone answering has used the same bottle you are holding, which removes a variable from the conversation.
Frequently Asked Questions
What is the difference between Vallejo thinner and flow improver? Thinner reduces viscosity so the paint can atomize. Flow improver reduces tip drying and keeps paint moving at the needle. Vallejo describes them in exactly those terms, and they solve different symptoms rather than being stronger and weaker versions of each other.
Can I use Vallejo thinner with other brands of paint? Within the water based acrylic family, generally yes, and plenty of painters run one thinner across several ranges. It will not work properly with alcohol based Tamiya acrylics or with lacquers, which have their own products.
Is Vallejo airbrush thinner just water? No. Vallejo positions it as extending the color and increasing fluidity without changing the paint’s properties, which is a different result from diluting with water. Water thins the binder along with everything else, which costs you adhesion.
How much flow improver should I add? A small proportion of the mix, added when tip dry is the problem you are actually having. Too much leaves coats slow to set and prone to marking under tape. Our article on tip dry covers the free fixes to try alongside it.
Which bottle size should I buy? The larger bottle if you paint regularly, since thinner is the fastest consumable on the bench and it keeps well when closed. A dropper sized bottle on the desk refilled from the large one is the setup most people settle on.
The Bottom Line
Buy 71.161 first, because thinning is the skill that fixes the majority of early airbrush problems, and add 71.462 when paint starts crusting on the needle rather than as a matter of course. Keep the cleaner well away from the mixing end of the bench. Start around four or five drops of paint to one of thinner, judge by how it runs off the stirrer, and the two bottles will cover almost everything you meet. Read next: the Vallejo paint ranges explained and which thinner matches your paint.