How to Dispose of 3D Printer Resin?

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Martin has a M.Sc. in physics and has gained many years of experience in industry as a lab manager and quality assurance manager. He has now tested dozens of 3D printers and is happy to share the collected experience with each new article.

Safety

Synthetic resins are aggressive chemicals in their liquid state. They only become harmless when they have hardened. So you have to treat resin like a chemical and protect yourself from it accordingly.

The best way to protect yourself is with the following personal protective equipment:

If you are looking for disposable gloves, you should choose nitrile gloves because they are chemical resistant. This will prevent contact between your skin and the residue, even if you work with the gloves for a longer period of time. However, make sure they don’t have holes in them or get them during use.

One of the biggest drawbacks of resin printers is the toxic gases that resins emit in their liquid state. So you should always make sure that you are in a well-ventilated room and wear an FFP2 mask. Your lungs will thank you for it!

Unfortunately, safety goggles are neglected in the risk assessment of most users. But safety goggles are very cheap and can pay off extremely. Getting a splash of liquid resin in the eye is no fun….

If your health is important to you and you want to take fewer risks, there is also ” target=”_blank” rel=”noreferrer noopener sponsored nofollow”>Eco-Resin from Anycubic* which is not as aggressive as normal resin.

Filling the Resin Vat

In preparation for any SLA 3D print, you will need to fill the resin tank of the 3D printer with resin. You should wear your full protective gear and have paper towels and isopropyl alcohol* ready in case something goes wrong.

If some resin is spilled or a drop runs down the bottle, you can simply soak up the liquid resin with a paper towel and wipe it off. To be on the safe side, wipe the area with isopropyl alcohol.

I’ll explain later how to properly dispose of the contaminated paper towels and your gloves as well.

Cleaning

Once the print is complete, you should prepare for post-processing before opening the printer. Place paper towels in front of the 3D printer so you don’t drip resin on the table when removing the print plate and resin tank. And don’t forget your protective gear!

Between the end of the printing process and admiring your finished print object, you need to clean the 3D printer:

Remove the print bed
Clean the print bed
Pour the remaining resin into the bottle
Clean the resin vat

Remove the print bed: During this step, some resin may drip onto your printer or table from time to time. As long as you wear gloves and have paper towels and isopropyl alcohol on hand, this is not a problem. You can simply wipe the drops away and clean everything with isopropyl alcohol afterwards.
You can place the wet print bed together with the print object on the previously laid out paper towels. There you can carefully detach the print object.

Clean the print bed: After printing, a lot of liquid resin will still adhere to the print bed. You can wipe this off with paper towels and then remove it completely with paper towels soaked in isopropyl alcohol. The cleaned print bed can then be reinstalled in the printer.

Pour the remaining resin into the bottle: You can reuse the resin left in the vat. Often, however, other areas besides the print object harden during printing. Most of the time these are only partially cured, slimy residues. Therefore you have to pour the resin back into the bottle through a fine filter (there are special resin filters for that >link to amazon*). Otherwise, this residue will cause printing errors in future prints. You can clean the filter and the funnel with alcohol afterwards.

Clean the resin vat: Clean the resin vat in the same way as the print bed. You can wipe off the coarse residues with paper towels. The rest can be removed with a paper towel soaked in isopropyl alcohol.
Be careful with the FEP foil at the bottom of the vat. It is very sensitive to scratches and dents. You can replace it, but you will increase its life span considerably if you are delicate when cleaning it.

Curing

Liquid resin is toxic. Cured resin is not toxic.

Except for the liquid resin that you still need for future prints and poured back into the bottle, you should therefore cure all resin residues with UV light.

You can cure the resin either with sunlight or a UV lamp.

The complete curing of the resin is the most important step in the disposal process!

I myself use the UV lamp for the print object and let everything else cure outside in the sun. If it is slightly cloudy, this is also not a problem, as enough UV rays still arrive – it just takes a little longer.

Even if you have a defective print object, you should cure it completely under UV light. Only then can you safely dispose of it.

Disposal

If you do not want to dispose of the liquid resin or objects contaminated with it professionally, you should cure all remains as described above. Only then is the disposal without risk.

Never pour liquid resin down the sink/drain! Not only can it damage the pipes of your sewage system, it is also very harmful to the environment.

Disposing of Paper Towels and Gloves with Liquid Resin

It can be very tempting to just throw the contaminated paper towels and gloves in the trash after use. However, not only does this harm the environment, it can also harm you and your family, as the liquid resin can still emit toxic gases.

Therefore, you should expose the used paper towels and gloves to UV or sunlight until the resin is completely cured. Only then is it safe to throw them away.

It is therefore also advisable to use as few paper towels and gloves as possible. This will not only save you time on disposal, it is even more environmentally friendly as you will waste less material.

Disposing of Resin-Alcohol-Mixtures

After you have removed the printed objects from the print bed, they go directly into a wash & cure station or into an isopropyl bath. There the excess liquid resin is removed.

The resulting mixture of isopropyl alcohol and resin cannot simply be flushed down the sink. Here, too, the resin must be completely cured beforehand.

Again, UV light or sunlight is the solution.

In principle, there are two ways to do this:

You place the mixture openly in the sunlight: the alcohol evaporates. The resin remains and hardens in the light. You can then dispose of the remains in the normal trash.
You irradiate the closed, transparent housing with UV or sunlight: The alcohol does not evaporate, but the resin hardens anyway. Afterwards, you can filter the mixture and dispose of the hardened resin residues in the normal trash.

In my experience, the second method is the better way. The first method often creates a “resin slime” rather than completely curing it.

If you put the alcohol-resin mixture after 1 to 3 prints in a closed PET bottle outside in the sun and filter out the remains afterward, you will be faster. And this way you don’t waste too much alcohol.

To make sure that even those residues are completely cured, I let the filtered-out resin residues cure even further in the sun.

Full Guide:
How to Dispose of Isopropyl Alcohol (IPA) with Resin? Guide

Disposing of Old Resin Containers and Bottles

When disposing of old resin containers, many often overlook the fact that there is still some liquid resin left inside. There is still a fine liquid layer of resin on the inside walls.

To get rid of the remains inside you have these options:

Cut open the bottle and cure the resin with UV or sunlight.
Wash out the bottle with alcohol and treat the resin-alcohol mixture as described above.

You can also simply place the bottle open in the sun and wait for a long time. After some time the liquid resin inside will harden anyway, even if only very little sunlight gets into the bottle. But whether it takes a few days more or less is no longer important.

Storage

Since resin hardens with UV light and is toxic in its liquid state, you should store it in a dark and safe place.

Most of the time, the resin bottles have already been designed by the manufacturers to not let UV rays through, but better safe than sorry.

Also, these bottles are usually equipped with a child safety lock. Nevertheless, the place of storage should be inaccessible to children.

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