How long does model paint last? A Guide on How to Know If the Paint is Still Good

There is a lot of conflicting information about how long model paint lasts. This is because it all depends on the quality and brand of the paint and how it’s stored. Model paint will last longer if stored in a cool, dark place, away from moisture and temperature fluctuations. When stored properly, model paint can last years! But generally speaking, how long does model paint last?

Generally speaking, model paints last for about 5-10 years if sealed in a tight container or left unopened. Furthermore, model paint that is appropriately stored can last longer than 10 years. However, make sure to test if the old model paint is good enough before painting.

This blog post will talk about how long do model paints last. We will talk about the factors that can lessen its lifespan, a simple test to know if you can still use the paint, and why we shouldn’t use paint that went bad.

How Long Does Model Paint 

How long is model paint good for?

As a general rule, model paints can be good for 5 to 10 years if left unopened or tightly sealed. However, opened paints that aren’t appropriately stored can go bad in a few months. Model paints older than 10 years still work but aren’t recommended for serious projects.

While we already know that most paint lasts for 5-10 years if left unopened, we need to understand why paint goes bad.

Basically, old model paint goes bad because its chemistry was altered due to the environment. This can be because the paint dried up or the solvent had already evaporated.

It can also be that the pigment’s integrity broke down due to oxidation and other chemical reactions.

Old model paints can easily crack upon drying because their integrity breaks down due to oxidation. Furthermore, changing the pigment’s chemistry can cause it to be undissolved in the solvent.

That’s why some old paints tend not to have consistent color, with some parts leaving a brighter or darker color than the others.

This is because the pigments start to be improperly mixed within the paint.

That’s why if you’re in a very important project or build, using old paint is not a good idea. Not only does it produce an inconsistent color, but it can also crack easily, which makes the job more complicated because we need to repaint the model.

Furthermore, if we aren’t careful with the painting process, dried paint or clumps can cause irregularities to our models, making our models’ surface rough.

The good news is that checking the consistency of colors is simple, as you can see the irregularities upon checking the paint.

However, it can be challenging for people to check paint build-up if they don’t know how to assess it. But, don’t worry because that’s the topic for the next section.

But for now, I would like to share with you some of the things to look out for when trying to store your paint.

Because let’s admit it, some of you who are reading this post are checking this because you want to know if you can store your paint correctly to maximize its lifespan.

Thus, I prepared some things you need to watch out for when storing your paint.

Here are the things that can affect your paint:

  1. Contaminants
  2. Rapid changing of temperature
  3. Freezing Temperature
  4. Sunlight or UV Exposure
  5. Exposure to air or oxidation
  6. Excessive heat

I’ve talked about some earlier in this post. However, I haven’t spoken much about UV and oxidation.

Basically, oxidation is a chemical process that happens when the paint is exposed to air or oxygen. The exposure causes some chemical reactions, particularly on the pigment, which causes it to reduce its solubility.

The reduction in solubility causes the paint to show inconsistencies because it doesn’t dissolve as quickly as before.

Furthermore, oxidation is causes discoloration. That’s why the paint might go yellowish when it is old.

The bad thing is UV or sunlight speeds up the oxidation process. That’s why it is a good idea to keep your model paint in a place away from sunlight to preserve them.

Furthermore, paint is temperature-sensitive. That’s why many people tend to use temperature or heat to dry their paint fast.

The bad thing about keeping your paint at freezing temperatures is it affects the chemicals inside the paint, making it go bad or expire faster.

Lastly, contaminants are destructive when it comes to preserving your models.

I talked about this in my other post, but the general rule is contaminants such as bacteria can also accelerate the oxidation process. As we talked about earlier, oxidation causes the paint to go bad.

I made a blog post on how contamination causes even plastic model kits to go bad. If you’re into plastic kits, it is a good idea to know how to take care of your models to prevent deterioration properly.

You can make your plastic kits last 50 years or longer with the right tips. If you’re interested in knowing how to prolong the lifespan of your plastic model kits, feel free to check this blog post: How long do plastic model kits last and how to take care of them?

For now, let’s talk about a simple test to make sure your old paint is still useable.

Can old model paint be used?

Old model paints can be used if the color or pigment is still consistent and doesn’t show any signs of drying. Furthermore, model paints that can’t be used tend to have inconsistent dyes affecting the paint quality. Similarly, old model paints that show signs of drying tend to produce imperfections in the finished model kit.

We already talked about a simple inspection to check if the color is still consistent in the paint. This makes sure that the paint can still give consistent color, which is a good sign that it is still good.

However, it’s not that simple. Sometimes, paint build-ups can signify that the paint isn’t stored correctly.

Furthermore, clumps of paint can signify that the paint has been contaminated.

So, what can we do to check for clumps?

Old paints can be easily be tested for clumps but stirring them with a stick for a few minutes. If dried strings of paint are attached to the stick. This is a sign that you need to get a new one.

The good news is these clumps tend to adhere to the stick when you stir it. Thus, if you see some clusters, then it is not a good idea to reuse the paint.

Others try to fix this by adding pain thinner. This method works if you don’t want to get a new one. However, this method messes with the paint to solvent ratio, causing the paint to be usually brighter or lighter than its original color.

Since you added more solvent, this makes the paint color lighter. Sometimes, this also means you need to apply more paint to achieve the right color.

So, I don’t recommend reusing the paint when it is dried.

One of the most common model paint is Tamiya paint. It is one of the best, and it is my favorite when it comes to model painting.

Thus, I made a section below talking about Tamiya paint.

Does Tamiya paint expire?

Generally speaking, Tamiya paint has an expiration of about 5 to 10 years. However, opened ones last for about 2 months to 4 years, depending on how you store the paint. Many factors can affect how long paint lasts but testing the paint if it is still good is easy.

Tamiya paint is one of the best ones to use in model painting. However, it is expensive. That’s why some people tend to ask if they can use their old Tamiya paint.

Generally speaking, the answer is that Tamiya paint that is stored properly can be good for about 10 years. However, this is only true if the paint is tightly sealed and is stored in a cool and dry environment.

The good news is testing the paint if it is still good is easy. First, check if the pigments are still consistent. If it is, use a stick to check if there are clumps.

If the paint passes both of these tests, you may reuse your Tamiya paint without any problems.

Remember to close it tightly and store it in a cool and dark place after using it.

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