Overview: Why I Filter Alcohol.
Save the Fish!
While resin 3D printing is an amazing hobby that has taught me a lot about machine management and repair, lab safety, computer aided design, and product deployment. Working with resin is MESSY. Really. Really. Really messy. And in its uncured/liquid state it is an irritant to skin and lungs. But I can put on some gloves... The problem is the disposal of these toxic materials into the ocean. Studies have shown that uncured UV resin is incredibly toxic to fish, leading to deformations or even destruction of habitats. Thus, I would like to share the system I have implemented to effectively minimize (almost completely) the amount of resin waste I output. Most of which comes out of the liquid residue from alcohol used to clean resin prints after post production. #savethefish!
Save the Money!
And if saving aquatic environments is not enough of an incentive, recycling IPA is incredibly important due to its high cost. A gallon of IPA costs roughly $15. And lasts anywhere from 1-2 weeks before getting contaminated with resin, depending on printing frequency. Now $30 per month on cleaning-alcohol costs is incredibly high when you are trying to run a profitable 3D printing business. So this method allows for constant use of the same IPA to get the most out of those dollars.
Save the Time!
If you need even more reason... I mentioned before that in disposing of contaminated IPA and liquid resin, NONE of it should be going into the sewer or regular trash containers. Rather, these materials must be taken so special recycling facilities where they can dispose of toxic materials in a relatively safe way. At least hopefully more safely than going straight into the ocean to pollute aquatic life instantly. Thus, recycling IPA allows for continued use of the material, without having to spend extra money, saving time on trips to toxic disposal centers, and resulting in clean resin prints.
Materials: The 3 Container System
This system consists of 3 containers. The first is the cleaning tub(middle) I use for new or clean Isopropyl Alcohol (99% IPA). This is what I use to clean my resin prints from excess liquid resin, so it must be kept relatively clear so that it does not clog or leave unwanted residue on finished prints. However, after a couple prints, this container easily gets full of liquid resin particles that are insanely difficult to filter out.
The second container is an air-tight jar(left) I store contaminated IPA in. And the third is a large bucket(right) I use to transfer and filter the alcohol from one container to the next.
It is worth noting that I use 190micron filters for this process, as well as nitrile gloves, a half facepiece Elastomeric respirator with vapor filters, and sealed safety goggles. While the safety components might seem excessive to some. YOU DO NOT WANT **uncured RESIN ANYWHERE NEAR YOUR EYES or skin. And taking the most preventative safety measures is essential in my lab.
Process: Four Easy Steps
Step 1: Cleaning the Cleaning Tub
The first step is to remove all the contaminated alcohol from the cleaning tub thoroughly, and into the transfer bucket using a thin filter. This will get rid of large pieces of cured resin from print supports, or broken pieces but most of the uncured liquid resin will remain in the alcohol.
Step 2: Into the Curing Jar
The next step is to transfer the IPA into a sealed jar. Which will be left out next to a window or outside to use the sun's UV light to cure the particles. This is why it's important that this jar is clear so that the light can flow through completely and cure the resin. After this jar is left out in the light. There should be a sludge-like substance forming at the bottom of the jar from the individually cured particles sinking. As well as a relatively clear IPA at the top.
Step 3: Filtering out the sludge
After the sludge forms I take another filter and dump the now clean alcohol into the transfer bucket. Leaving behind the sludge in the filter. Then I transfer the clean IPA back into the cleaning tub or into the jar depending on where I need it.
Step 4: Neutralizing the sludge
This is perhaps the most important step in the process. I mentioned in my overview that uncured resin is toxic to aquatic life and thus should not be disposed of in the trash or sewer. By completely curing the remaining resin, I ensure that it will not pollute the ocean by allowing particles to contaminate the environment. So I simply place the sludge in my curing station or leave it out in the sun, forming a resin rock that can now be safely disposed of.
Conclusion
Filtering out resin from IPA is incredibly important to a sustainable printing station, it saves some money on extra materials, and it helps preserve the environment. Perhaps it is not the ultimate solution to produce truly zero-waste prints, but it's pretty close! Happy printing :))))
