I think combining liquid masking and masking tape can improve work efficiency

Since I received a question on Patreon, I thought I’d write about liquid masking.

There are already many articles comparing different masking liquids or describing actual usage. I think many people already know about the basic types—rubber-based and vinyl-based—and their properties. So the real question is, how should you actually use them differently? That’s what people want to know. In this article, I’ll cover:

• Specific uses for rubber-based and vinyl-based masking liquids

• Combination of masking tape and masking liquid

• What kinds of applications are possible

If you’re simply curious about the performance of each manufacturer’s product, please check YuzuP’s blog for comparison articles.

Reference article: Masking Zol Performance Comparison! Master this convenient tool for painting plastic models accurately!
https://yzphouse.com/maskingzol

┃Brief explanation of rubber-based and vinyl-based masking liquids
As mentioned at the beginning, masking liquids can be divided into two types: rubber-based and vinyl-based.

Here’s a quick summary of their properties. Basic performance is similar across all manufacturers, so I’ll omit minor differences such as availability or color variations here.

If you can’t tell the type just by color, check the product description—if it mentions things like "cut with a cutter," it’s usually vinyl-based.

Rubber-based and vinyl-based are opposites in function

★ Rubber-based:

• Low viscosity, flows smoothly

• Dries within about 2 minutes; can be accelerated with hot air from an embossing heater

• Highly visible before and after drying, so you can easily see where it was applied

• Easy to peel off by sticking the dried rubber to remove

• Stretches when peeling, so paint flakes can scatter (can solve by using a dust collector while peeling)

• Dries faster as the amount decreases

• Difficult to cut with a hobby knife after drying

• Does not adhere well to the surface, so edges can get messy

• Not resistant to enamel or lacquer solvents

★ Vinyl-based:

• High viscosity, thick, harder to apply

• Even a thin coat requires 10 minutes to dry; thick layers may need 30–60 minutes

• Low visibility before and after drying, so you risk masking failure if you overestimate

• Strong adhesion to the surface; peeling requires lifting from the edge with a knife

• Does not stretch when peeling, so paint flakes don’t scatter

• Drying speed does not change much as the quantity decreases

• Easy to cut with a hobby knife after drying

• Can be diluted with water to remove if peeled mid-dry

• Adheres well, producing clean edges

• Resistant to both enamel and lacquer solvents

In short, the last two points—surface adhesion and solvent resistance—greatly affect work efficiency.

┃Small portions last longer

As mentioned, masking liquid dries faster when exposed to more air. Especially for rubber-based liquid, the solvent can evaporate quickly, and even a mostly unused bottle can dry out and become unusable.

To maximize efficiency and use it completely, you need a storage method that minimizes air exposure.
Vinyl-based liquid dries but won’t become completely unusable even if a whole bottle is exposed.

For rubber-based liquid, storing the bottle upside down (with a tightly closed lid) prevents solvent evaporation, making it last longer regardless of storage temperature. It may seem minor, but it really works.

Transferring the liquid to a small bottle before use also reduces air exposure, prolonging its life. If the metal nozzle clogs, a 0.5 mm brass wire can be pushed through to clear it.

Practical usage examples based on properties

★ Rubber-based: Prevent leakage at masking tape seams
Low viscosity and fast drying make rubber-based masking liquid very easy to work with, even when applied roughly.

For example, when painting Cocoro’s cape, masking tape covers almost everything. Due to the uneven surface, tape alone tends to lift over time, causing gaps. Spraying over these areas almost always results in leakage, so rubber-based masking liquid is used to fill seams.

★ Rubber-based: Can be used directly on clear steps
If there are clear edges and large steps, you don’t need to insert thin masking tape.

★ Rubber-based: Insert thin masking tape if there’s no large step

Rubber-based masking alone may not create clean edges, so using it with thin masking tape allows for neat and quick masking. Using only tape can take more time and risk gaps.

Peel rubber-based masking carefully using a dust collector to prevent flakes from scattering—this alone results in clean painting.

A subtle technique: intentionally mask slightly over the edge and then touch up with a brush afterward. It’s very minor but effective, often done in areas not visible in videos.

★ Vinyl-based: Take advantage of solvent resistance
Rubber-based alone works for most normal tasks, usually with thin layers. If thick layers require masking, I use vinyl-based.
Rubber-based can lift when exposed to solvents. That’s why I only use vinyl-based for masking eyes during final matte coating.

For example, during Kafka’s eye painting, the skin color didn’t match. So the eyes were protected with vinyl-based masking, then lacquer solvent removed the skin color to repaint.

While the eyes are protected, carefully remove the skin color using a small brush. After that, repaint the skin. Always allow at least 30 minutes drying time; even with solvent resistance, incomplete drying may cause peeling.

Vinyl-based also adheres well, producing clean edges. However, its high viscosity and longer drying time make it suitable mainly for these picky applications.

If you have better methods, please share in the comments!