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7 Ways To Know When a Resin Print Is Fully Cured

Working with resin in a 3D printer allows you to make just about any object! There’s a lot of freedom to be creative with your designs. However, you’ll need to learn how to cure your resin objects properly, or they won’t turn out.

Here are 7 ways to know when a resin print is fully cured: 

  1. It doesn’t look wet.
  2. It has a matte surface.
  3. The color has dulled.
  4. You used an appropriate average curing time.
  5. You used isopropyl alcohol.
  6. Test it by gently touching it with a toothpick.
  7. You’ll learn with experience.

There are seven main ways to tell if your 3D resin print has cured thoroughly, and in the end, it’ll all come down to practice and gaining experience. In this article, I’ll go into more detail about each method in this list to help you learn how to find a nice balance for your curing times. Let’s get started!

1. It Doesn’t Look Wet

When you first take your object off the printing table, it’s going to look wet. You’ll want to handle it with care and ensure the uncured resin doesn’t get on your skin since it’s toxic.

It won’t look glossy as your project cures under the UV lamp. You want to give the project enough time to dry thoroughly. Usually, it’s easy to tell when the object isn’t wet anymore. You should also rotate your project under the UV light reasonably often.

If you don’t, then the piece can’t cure evenly! You’ll end up with sides that still look wet and glossy, while other sides are dry. Keep in mind that smaller figures don’t take nearly as much time to cure as large ones. Small objects may only take 2 minutes, while large ones could take 8 hours. It all depends on the thickness of the material and what type of resin it is.

This YouTube video has plenty of information for getting the perfect curing time with every print that you make:

2. It Has a Matte Surface

As your piece starts to cure, it’ll become more and more matte. Matte means it won’t have any shine to it. Stop curing when you notice the gloss is gone to avoid over-curing the resin.

You must know precisely what kind of resin you’re using to determine when it becomes fully matte. You can look up the brand on their website quickly. From there, you should find information on the curing times for the unique type of resin you have.

Even among brands, their resin products can have different curing times. Knowing what to expect can help you notice when the object develops a matte surface.

3. The Color Has Dulled

When your object comes off the printing table, it’s going to be a lot brighter than the final cured product. While it won’t be as vibrant, many people paint over their figures anyway.

The resin dulls as the water evaporates from the UV light, causing it to dry and cure. You may even notice small amounts of steam leaving the figure! It’s finished curing when it’s dulled significantly. It may even look a few shades lighter than when you took it from the printer.

4. You Used an Appropriate Average Curing Time

As I mentioned before, it’s always a good idea to use the brand’s recommended curing times. They’ve likely tested their product many times to get those numbers! However, if you can’t find that information, simply use these average curing times to get a better idea of how long it should take your models to cure fully:

UV Curing MethodSmall PiecesLarge PiecesTransparent Pieces
Natural Sunlight2 to 4 hours4 to 8 hours 1 to 2 hours
UV Lamps 2 to 5 minutes5 to 20 minutes1 to 2 minutes
UV Curing Station2 to 5 minutes 5 to 20 minutes1 to 2 minutes

It’s important to check on your 3D figures often while they go through the curing process. You’ll need to rotate the object to ensure the UV light reaches it on all sides, especially when curing them outside in the sunshine. Notably, the resin becomes brittle and porous when it has too much exposure to UV.

5. You Used Isopropyl Alcohol

You should always clean your prints with isopropyl alcohol after letting them cure. Doing so prevents your objects from becoming sticky and helps them during the post-cure process. Isopropyl alcohol is perfect for this material since it evaporates quickly and leaves no residue.

This cleaning method removes leftover uncured resin, helping you get the perfect results! You should do it after most of the project cures, according to its recommended curing time. The alcohol should remove any sticky, leftover resin uncured from the rest of the project.

6. Test It By Gently Touching It With a Toothpick

If you can’t tell a cure is finished by looking at your project, very gently and carefully touch it with a toothpick. The project needs more time to cure if it’s still feeling soft. However, if it’s hard, it’s likely fully cured at this stage.

If you don’t have a toothpick, another small item you can easily control with gentle force will do. Just avoid handling uncured resin directly (and always be sure to wash your hands when you’ve finished working on your objects). 

7. You’ll Learn With Experience

Overall, you’ll learn the perfect curing times to gain more experience! With every print you create, you’ll get a better sense of how long it takes. As you practice using this material more, you’ll better understand your average curing time. 

Everyone has a different setup for making resin prints and using other materials. Therefore, it can take everyone various amounts of time to reach the perfect cure on their items. You’ll want to make a lot of test prints and experiment to get a feel for how your setup functions.