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Inspired by this question, I suddenly wondered if there is a type of ink that would dissolve slightly as the epoxy resin sets.

Say that a text gets printed on a sheet of white opaque acrylate, and, like in the linked question, gets cast in a block of resin, is there a kind of ink that would slowly lose its bond with the acrylate sheet as the resin gets cast and hardens, so it would appear as if the text is permanently evaporating?

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    There should be, I reckon. You'd need a slow setting rather runny epoxy in addition. Aren't there alcohol-based dyes for epoxy? I wonder if they're strong enough to be used as ink. I don't have casting epoxy but I know the permanent markers, I use in work do something similar in our acrylic resin (used to prepare samples). A test with those may be in order. All speculation; I'll answer if I figure out a test with what I've got here.
    – Chris H
    Jan 16, 2022 at 20:37
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    @ChrisH Well, I like the testing phase, so once I get my hands on some supplies, I'll try it out. Thanks!
    – Joachim
    Jan 16, 2022 at 22:06
  • Another thought: do you have to use epoxy or would an alternative chemistry be acceptable?
    – Chris H
    Jan 18, 2022 at 10:37
  • @ChrisH Another type would be completely fine, too.
    – Joachim
    Jan 19, 2022 at 6:15
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    There's an alternate approach that can work if you will only view it from the top/front (like a framed piece; not true 3D, so viewing from the side wouldn't have the effect you describe). You print the "cloud" of ink particles as a series of layers/slices on transparency film, and stack those and resin layers over a print of the "degraded" image. It takes only a few layers to look 3D if you look through them, but would just be stripes if viewed from the side.
    – fixer1234
    Feb 6, 2022 at 21:29

2 Answers 2

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I've tried with some pens. I don't have casting epoxy, only slow epoxy glue (Araldite precision), but it's enough to demonstrate a problem or two within a few hours.

  • A water-based overhead projector pen (Guilbert/Niceday red) was untouched by the epoxy ("W" in the photo).
  • A solvent-based permanent overhead projector pen (Stabilo OHPen universal, also red) that is definitely alcohol-soluble, reacted with the epoxy and turned yellow ("O"). Not evenly though - overlap in the strokes still shows red at the moment.
  • A Sharpie (magenta) faded a lot, and really shows where the strokes overlapped (I went over a few times to get more ink down). I don't know if the fading is due to reacting or dissolving, but there's no dissolved effect visible ("S").

The top row is after a few hours under epoxy. The bottom row is a comparison with no epoxy. The substrate is clear PET (grabbed from the recycling bin)

Test of epoxy vs. pens

A further test in work with a green OHP pen and acrylic resin produced a tiny bit of diffusion, but nothing useful.

So I think you've got a couple of issues:

  • getting down enough pigment to be visible even after dissolving
  • chemical reactions between the inks and the epoxy
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    I still might try a dark blue Sharpie, and Epson inkjet ink on paper or OHP film if I still have any. Also interesting would be thinning the epoxy with alcohol (I have a little pure isopropanol here).
    – Chris H
    Jan 18, 2022 at 13:16
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    Kudos for the experiment! My experience with red dyes, pens and colors in general is that they are the most at risk of drastically changing colors. In my own experiment one red paint changed to sunflower yellow and the other one got a lot darker.
    – Elmy
    Jan 18, 2022 at 13:42
  • @Elmy there's a lot of useful stuff at your old question and in particular your own answer. I'd forgotten about it
    – Chris H
    Jan 18, 2022 at 13:52
  • Thank you, Chris! Those are already very good aspects to take into consideration. I'll see what inks I have at my atelier. I'll also try with oil paints, since the consistency and pigmentation seem like they could surpass a few of these limitations (but probably run into problems of their own :).
    – Joachim
    Jan 18, 2022 at 16:26
  • A further test in work with a green OHP pen and acrylic resin produced a tiny bit of diffusion, but nothing useful (added to the answer). Also a thought: a saturated solution of methylene blue in alcohol would make for a very strong blue dye that when diluted as it diffused might still be visible.
    – Chris H
    Jan 25, 2022 at 13:47
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There are 2 questions here:

  1. Is there an ink that's soluble in epoxy? Yes, see Chris H's answer for more details
  2. Can you cast a print in epoxy and make it dissolve just the right amount "so it would appear as if the text is permanently evaporating?" I think you must fake it.

Epoxy has - depending on the chemical composition - vastly different hardening times (from 5 minutes to several days) and consistencies (from water-like to putty). As it hardens, it produces heat, which produces movement in the still liquid resin. The result can be seen in this question where a faux tortoise shell turned out to harden in one solid color.

Add to all that the fact that printed text usually uses as little ink as possible, so printing enough ink to get the desired effect might need several passes.

To get everything right, you'll need the right kind of epoxy that lifts enough ink from the underground without diluting it into invisibility, you'll want to control the ambient temperature to get the resin to set right and you'll need to shield the cast from vibrations and other influences.

I honestly think it'll be easier to fake the effect by injecting tinted epoxy in the desired shape with a syringe. This technique is well-known and used to create veil-like effects. You can also dip the tip of a toothpick into tinted epoxy and draw a veil through the clear cast. One example of it can be seen in this YouTube video, but there are many more out there.

If you work with very liquid epoxy, you need to wait until it becomes viscous, or the veil may disappear again. Another YouTube video that explores this effect is this one. However, to squeeze epoxy through a syringe it must be very liquid. My advice is to either use 2 different epoxies (honey viscosity for the cast and very liquid for the ink) or letting the transparent cast become viscous for a while and then mixing a fresh batch of tinted epoxy.

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  • Thank you, Elmy! That's a very good idea, but to inject every single letter of a text will likely not give the right effect. I mentioned the acrylate sheet, not only because it must be harder to properly cast a sheet of regular paper in epoxy, but also because most inks will not dry easily on it. I was imagining that if the sheet is put in still liquid epoxy it might very slowly float down and the ink could potentially dissolve ever so slightly in a seemingly upwards direction. Do you think there is an ink that would create that effect? Or simply one that will reactivate in liquid epoxy?
    – Joachim
    Jan 18, 2022 at 9:58
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    @Joachim TBH I have never experimented with dissolving dried ink that way, but you must keep in mind that reality is never as perfect as you imagine. How long does the sheet need to sink down? How much drag will the liquid resin cause over the surface of the sheet? Or will all of the drag be around the edge and the center will be unaffected? Will the ink bleed sideways instead of upwards? I don't think you'll be able to create the desired effect without faking it. Maybe if you could heat only the spots with the letters, you could create an upward current, but I doubt it.
    – Elmy
    Jan 18, 2022 at 10:34
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    How important is the material of the sheet? I'm wondering about the sheet itself being a silk-screen, and injecting dye through that into resin on one side
    – Chris H
    Jan 18, 2022 at 13:17
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    That's why I was thinking silk-screen. I haven't done it for years (decades) but recall the screen material being plain white, then one single source of pressure would push the dye through the whole pattern simultaneously. The problem would be that an experiment would take a lot of effort. You'd use it in a similar way to needle injection described in the answer but the base image would also replace the needles (then you'd cast the back once everything was dry). Also you could push dye through more than once, as the resin started to stiffen, to modify the effect
    – Chris H
    Jan 19, 2022 at 10:28
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    I suspect you wouldn't actually want your diffuse cloud too perfect - if you look at smoke rising or inject ink into apparently-still water, the plumes are far more interesting than simple diffuision
    – Chris H
    Jan 19, 2022 at 10:28

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