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Do You Have To Filter Resin After Every Print?

Is filtering resin necessary after each 3D print? Learn the benefits of filtering and how often it should be done.

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Successful 3D printing is a delicate balance between preparation and execution. It is, therefore, only natural that questions about what to leave out or remove after every print abound, given the impact that this may have on print quality. Should you filter the resin after each print or not?

You don’t have to filter resin after every print. However, you’ll have to keep the resin in a cool, dry place and away from UV rays and direct sunlight to prevent curing. Under optimal conditions, you can leave the resin in the tank for up to two months.

The rest article will discuss when you can and cannot leave uncured resin in your 3D printer, including whether you should leave the resin in the tank between prints and why or why not. 

Can I Leave Resin in the Tank Between Prints?

You can leave resin in the tank between prints without experiencing any issues. However, you must keep it safe from dust, light, and temperature fluctuations to prevent it from clumping up. 

While many people worry that leaving the resin in their vat will ruin it, you can leave uncured resin in the 3D printer tank for several weeks without a problem.

Still, there are several steps you must take if you want to leave the resin in the tank. For starters, you will need to keep it in a cool and dark area for the duration it remains in the tank between prints. 

You should cover the entire resin printer and place it in a cool dark room. Protecting it prevents the resin from hardening by blocking out any light that could compromise it.

Secondly, when you are ready to use the resin again for your 3D prints, it is important to stir this resin until it is in a fluid state. Mixing the resin before beginning your 3D printing process after it’s been in the tank for a few days or weeks is essential to detach any hardened resin before you start printing. 

Therefore, whether or not you need to filter the resin comes down to a few helpful questions. Let’s explore some of these below:

Does Your Room Get a Lot of Sunlight?

If your printing room has any windows, leaving your resin in the tank after every print is not a good idea. Still, it might be fine if you can cover the printer and the printing room from direct sunlight. 

If your room receives a lot of sunshine, I recommend filtering the resin after every print and storing it in a container for proper storage. 

However, if your 3D printing setup is in a cool, dry place with little sunshine, such as a cool basement, you can leave the resin in the tank between prints, as it will not harden. 

Consider purchasing a specialized UV cover to protect the resin between prints if your room has windows. Even if light pierces the cover over time, you can easily keep your resin in printable condition by mixing it with a plastic spatula to prevent hardening. 

I recommend getting your hands on the Mach5ive Elite Blackout Cover (available on This cover provides ample coverage to keep UV rays and moisture at bay while containing resin fumes. It is easy to install and flaps on all four sides for unhindered printer control and port access. 

Which Conditions Affect Resin?

Knowing the conditions that affect resin when not in use is essential. One of the most common misconceptions is that the resin may harden if you expose it to air, which is incorrect. 

Exposure to air will not cause the resin to harden. Instead, it will only cure if you expose it to warm temperatures or direct sunlight. 

How To Determine if You Need To Filter 3D Printing Resin

You do not have to filter the resin with every print. The main objective of filtering the resin is to remove any parts of the resin that may have hardened due to exposure to direct UV rays. 

Granted, whether or not you need to filter the resin will depend on the period between prints and whether or not it has hardened. As previously stated, this will also depend on the conditions of your printing area. 

You will only need to filter the resin back into the bottle if you notice scummy, hard, or lumpy bits in your printer’s vat. However, beginners need to filter it after every print to increase their chances of success. 

How Long Can You Leave Resin in the Tank?

The time you can leave resin in the printer tank without issues ranges from a few days to several months. However, this will depend on many factors, including the storage conditions and the conditions of your print area.

Look at the video below to learn more about how storage conditions affect the time you can leave resin in the printer tank.

It’s always a good idea to use a plastic spatula to regularly mix the resin in your vat to prevent premature hardening. The uncured resin can stay in the tank for up to a year, as the video below explains.

However, the caveat is that you must keep it away from warm conditions, direct sunlight, and dust and stir it occasionally to prevent solidification. Still, even then, most resin manufacturers recommend disposing of resin that has sat in the tank for more than two months.

That is because, if you leave it in the tank too long, the resin might thicken and adhere to the screen, damaging it permanently.


There are several key takeaways from this article:

  • You don’t have to filter the resin after every print if it has not solidified
  • Exposure to warm conditions or sunlight causes the resin to cure
  • Stir the resin with a plastic spatula during storage to prevent solidification
  • Filter out any hardened residue over time to improve print quality 

These tips should prove helpful in guiding your 3D printing journey using resin.

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About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.