Can You Cure Resin without UV Light?

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The possibility of curing resin without UV light is a question on many people’s minds. For us, we like finding novel ways to do things. That instinct was what drove our team to examine whether it’s possible to cure resin without UV light or not. In the course of our research, we learnt a lot of things, and we are willing to share them with you in this post.

Can you cure resin without UV light? You cannot cure UV resin (also known as 1-part resin) without UV light. But 2-part resin is not UV-sensitive, so it can cure without UV light. What’s more, for UV-sensitive resin that requires UV light to cure, the UV source can be ambient light from the sun. Direct sunlight exposure is enough to cure resin, but it might take more time than high UV wavelengths from a professional UV curing machine.

How does UV light cure resin? What is UV resin and how is it different from 2-part resin? How does 2-part resin cure without UV light? There are many questions that beg for answers. As you read on, you will find answers to these questions as many more. If you are curious to learn about this topic, make sure to read this post to the end.

Can you cure resin without UV light?
Photo by Rob Wingate on Unsplash

How to Cure 2-Part Resin without UV

While UV resin requires UV light to cure, the 2-part resin contains both resin and a hardener that facilitates curing after you have printed or molded your 3D part. There are other resin types, but the two most popular types are UV resin and 2-part resin. 2-part resin is made up of two solutions – resin and the hardener. You are to mix these two solutions in equal amounts for curing to be effective and complete.

2-part resin includes wet liquid-like resin and a hardener, which is usually also in liquid form. After making a mixture of these two liquids, the hardener begins to cure the resin until the model becomes hard. This process, however, takes about 3 hours to complete for small models. UV curing, on the other hand, takes only about 15 minutes for models of similar size.

When to Use UV Resin vs. 2-part Resin

UV resin is good for printing jobs that apply resin layer by layer to create a 3D model. 2-part resin, on the other hand, is more suitable for casting jobs, where you use a mold to create 3D models. What’s more, the 2-part resin is somewhat more versatile since transparency is not an issue. But curing 2-part resin takes days, unlike UV resin that can be cured in minutes.

If you are curing resin without UV, you will need to exercise patience. The mixture will still be malleable after 24 hours. But if you wait for about 3 days, it will cure fully. Although the time is long, the results are usually very satisfactory. After curing is complete, you can sand and file the model or even drill a hole in it.

✅ Video – Confused About 2-Part and UV Resin? Learn the Difference!

Sandy Huntress is an expert at what she does – making 3D crafts. She knows the in and out of using resin to create 3D parts. In this video, she clears the confusion on how 2-part resin differs from UV resin. After watching, you will no longer be confused about these two resin types.

Other Ways to Cure Resin without UV

Aside from UV light and hardening substances, other methods of curing resin include the use of temperature and certain solvents. A more recent method is the use of blue light for small models. These different methods can cure various types of resins, glues, and inks.

Below is a list of the different other ways to cure resin:

Hardening Solvents

You can dissolve your resin substance in certain hardening solvents to facilitate curing. After you have finished making your 3D part, you would expose the model and allow the solvent to evaporate away slowly. This is how a lot of resin-based glues work.


Heating resin substances also facilitate curing. High temperature mobilizes and agitates the molecules in resin. As the molecules collide, there form bonds that make the model harder and stronger. If the temperature of the room is about 24-30ºC, the resin should reach 95% curing in 24 hours. And in 3 full days, it should cure completely. Ensure no to use excessive heat because it can cause discoloration.

Hardening Substance

We have talked about this while describing how 2-part resins cure. When mixed in the appropriate proportions, the hardening substance triggers the curing or hardening process.

Blue Light

Blue light is the closest light to UV on the spectrum of visible lights. It has lower energy than UV light, but it can still be used to cure very small resin models. The energy of blue light may, however, not be strong enough to cure large-sized models.

How Does UV Light Cure Resin?

The photons of UV radiation trigger a chemical reaction in resins. This reaction causes the small molecules in the substance to start linking together. This forms a network of large cross-linked molecules, which makes the model hard.

UV light initiates a chemical reaction, called polymerization. This reaction causes small molecules in resins to cross-link and form a network of larger molecules. This makes liquid resin to take a harder and more solid from. This hardening process is known as “curing”. Aside from resins, UV light can also be used to cure various types of glues and inks.

Extended UV exposure due to ambient light from the sun is enough to cure resin. But over the years, other means have been developed to facilitate the curing of resin without UV light. Some of these methods include adding a hardening substance to resin to create a 2-part resin. High temperatures can also facilitate curing, but it still requires UV light to cure resins.

Advantages of UV Curing Above Other Curing Methods

It Is a Faster Curing Solution

UV curing can be as fast as a few seconds or minutes if the 3D model is very small. A small model made with 2-part resin could take as long as 3 days to cure. Larger models take more time to cure, even under UV light, typically minute to hours. But other methods will require much longer time.

Temperature Flexibility

UV light can cure resins over a broad temperature range. Unlike other methods, you don’t have to heat or cool the resin to a specific temperature or range for curing to occur.

Offers Selectivity

UV light will cure only the area of your 3D substance that you expose to UV radiation. This means you can choose to leave certain areas uncured or to cure some areas first before others. Other methods do not offer this selectivity.

No Ventilation problems

Some resin materials dissolve in hardening solvents as you allow the solvent to evaporate away slowly. As the solvent fumes evaporate, they often create a ventilation problem. You would need ventilation to remove these fumes. However, with UV curing, ventilation is never a problem.

Drawbacks of UV Curing

The major drawback of UV-light curing is this UV light penetrates transparent substances better. So, if the resin material is not transparent, it may not cure completely since UV radiation will not penetrate its inner layers.

Also, UV curing is not the best for biomedical casts, such as dental fillings. While trying to set dental fillings with UV light, the radiation has harmful effects on the patient’s gums and other soft tissues inside the mouth. Recently, however, dental science has introduced new resin types that can be cured with blue light, without any UV content.

Related Questions

What is UV Resin?

UV resin is the type of resin that cures under UV light. Unlike other resin types, the post-processing of this resin type requires UV radiation to fully cure. UV resin is a ready-made mixture and you wouldn’t have to mix it before use. It is best suited for printing (layer upon layer application) than casting (pouring into a mold).

Since UV curing is faster, UV resin cures faster than other types. This reduces the duration of processing for your 3D parts. UV light sources for curing UV resin include UV lamps, UV torches, and UV curing stations.

How many watts to cure UV Resin?

To cure UV resin the minimum watts required is 4 watts. But for the best results, you should use 9 watts and above. Typical lights that can have enough watts for UV curing include the lamps used in nail curing and many UV LED flashlights. You can also use direct sunlight.

How to Cure UV Resin without Sunlight?

If you are using an artificial UV light source, you must use one that’s powerful enough to fully cure the resin. Hold the UV light source close to your resin model’s surface. You can station the lamp or torch with a stand but make sure the light is directed towards the model. If you are using a ready-made curing station, simply place the model in the station, switch on the station, and apply the appropriate settings.

Artificial UV sources usually cure UV resin faster than sunlight. More so, they are not subject to changing weather conditions. You can control the light and heat settings to suit your specific application. For more on this, read our post on how to cure 3D printed resin.


Evidently, UV light is the most common method for curing resin, but there are other methods too. More so, the different resin types use different curing methods. All of these different methods have their advantages and disadvantages. But UV curing seems to be the most common primarily because it is faster and has a wide application.

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