White Residue in tank using Castable 02

Hey Guys,

My last print was 6 days ago. Since then, the resin tray remained inside the machine with the lid closed - no black lid on top of the resin tray.

I went to set up a print and when stirring the resin there is some creamy white resin that seems to have separated. I kept stirring and stirring and eventually got it to mostly mix in.

In addition, there is some white flakey residue building up along the areas where the resin splashes up the side of the tank.

I haven’t tried to print since I noticed this. I plan to filter the resin when I get to work in the morning, but I wanted to leave a few questions here tonight to see if anyone has some insight.


  • Should I be removing and storing the filled resin tank in a completely dark place when the machine is not in use for a few days?

  • Are the flakes building up along the sides of the tank normal with the castable resin? What is the best way to clean them?

  • Is filtering the resin and cleaning the tank per Formlabs instructions the best way to ensure that my next print succeeds? Do I need to filter and clean tank or is this separation normal and solved by a bit of stirring?

Thanks for your help!

The separation is normal, I wasn’t printing for a few months because of moving and so the resin was sitting around for a while. Once I got everything ready to print again I had to stir the grey resin for quite a while to get it to mix up fully. After that it printed just fine.
If I’m not printing a while I put a box over the printer, I happen to have a box that fits it perfectly. The cover should be blocking the wavelengths of light that can cure the resin, but I still think it’s probably better to cover it. Plus it keeps dust away.

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To add to what Zachary_Brackin said, separation is normal but the white flakes usually mean that there’s been some sort of print failure whether that be full or partial. Filtering the tank normally should clean those out for you. Castable separates more than other resins so giving it a quick stir after a few days of inactivity is good practice.

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