Injecting materials into finished clear resin print?

Hi all,

I’m currently mocking up some projects that involve multi-material ideas, and planning to show colorful objects inside of clear resin prints. Initially I thought I would use silicone rubber (and still might) but I also would love to hear what others have done. I’m trying to inject silicone rubber inside of the clear resin in order to fill cavities and give the impression that the objects are just hanging inside of the clear print. Overall I would achieve this goal by leaving a small channel in my print, enough to fit a syringe for material injection.

I have also read a couple other threads where it sounds as though users have managed to “dye” interior walls, or inject liquid resin and let it cure inside the print (though I have a hard time believing the large cavities I’m trying to fill would cure entirely?).

If anyone has had success with similar ventures or different ideas, I’d love to hear them. Thanks!


Depending on the cavity you are filling (and the viscosity of your injected media) you may need to create channels to the exterior of the part to evacuate air. You can always back fill these with clear resin later and cure to make them nearly impossible to see. Just something to consider. If your injection site is large enough it might be a moot point.

I’m fairly certain Formlabs has written a blog entry on this exact process, search around and see if you can find it.

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You do not need to FILL the cavities.
All you need to do is PAINT the interior surfaces.

Its really easy; just inject a bit of paint, and rotate the clear model by hand to slosh the paint around on the interior until it is entirely coated, then pour the excess out the same hole you got the paint in by ( it would help to have a second hole somewhere that allows air in as the paint pours out. )

Any opaque color on an interior cavity will appear from the outside to be a solid material embedded in the clear material. Here is an example- this is a clear resin print that is flat on front and back- but has a negative space in the back in the shape of a cameo relief. I polished the front and back for clarity- but in the relief cavity I simply painted a cream color. Its still hollow- just the surface is painted opaque.

if you do this trick with translucent paints- then the effect can be of a colored liquid object suspended inside a clear object.


Sculptingman, that is STELLAR!!!
Do you make sculptures of people? Is it a .STL file in the end that can be printed over and over?
I have a need for one, of my step daughter that passed away… PM me.