Title. I’m looking for resins with the lowest Shore hardness, the lowest one I’ve found (that I can buy on aliexpress) is Resione F39, with Shore 60-75A. Ideally, I’d want to get something closer to Shore 30-40A.

So, failing that, anyone with a higher understanding of chemistry can explain what additives are usually added, resulting in a cured resin with greater elasticity?

  • SaveTheTuaHawk@lemmy.caEnglish
    2·
    1 day ago

    You need a silicone based resin. TPU based are 65A or stiffer. Stratasys or Formlabs make these down to 25A, but they are expensive. Very difficult to print most shapes as the print inherently sags. They print very slow, 30 second first layers.

    Spool3D elastic is 40A and inexpensive.

    https://spool3d.ca/spool3d-elastic-resin/

  • AnyOldName3@lemmy.worldEnglish
    3·
    2 days ago

    Could you perhaps print a mould and then cast platinum-cure silicone in it? This can be a pain, as lots of resins contain things that stop silicone curing, but some combinations work (e.g. some bbdino silicone I had cured just fine in contact with Sunlu ABS-like clear blue resin I had) or can be made to work (e.g. coating the resin mould with something that it’s more compatible with).

    If you don’t need the properties of platinum-cure silicone, you might even be able to get away with tin-cure, which is much cheaper and more tolerant of other chemicals.

    • darkmogool@feddit.orgEnglish
      2·
      2 days ago

      I’ve made silicone moulds with resin prints. The key (for me) to let the print off gas for about a month and the cure inhibition is gone. But not everyone has a month to wait.

    • I Cast Fist@programming.devOPEnglish
      1·
      2 days ago

      I’ve been trying to make/print a usable mold of the model, but due to its irregularity, i’ve been having a hard time doing so in blender, even with metaballs

      • AnyOldName3@lemmy.worldEnglish
        1·
        2 days ago

        If you’ve got a manifold mesh for the object you want, you could make a mould by getting a cube that contained it, using a boolean modifier to subtract the mesh from the cube, then adding one or more cylinders for pour holes at the high point(s) of the mesh and subtracting those, too. If you only need one of the object, so don’t need to reuse the mould, you can stop there and print it, then once you’ve cast it and let the silicone cure, just hit it with a hammer until the mould smashes and the silicone will probably be fine and pull out in one un-scarred piece.

        • I Cast Fist@programming.devOPEnglish
          2·
          1 day ago

          For the size I want to print, a pure cube won’t cut it, but I did manage to make a form-fitting mold by making the cube hollow, then removing the cube proper, being left with the mold proper.

          I’ve been spending quite some time trying to figure how to properly cut the mold into 2 or 3 parts in a way that I can actually close the thing and pull out the cured silicone without it deciding it’d rather stick to the cured resin. I’ve given some thought on making a single use mold, but I also gotta figure how to ensure its interior gets enough release agent to help me demold.

    • I Cast Fist@programming.devOPEnglish
      1·
      2 days ago

      Formlabs is WAY beyond my pay, I’m afraid. 349 USD is over 1500 BRL, and that’s the price without shipping or the 96% import tax. The Resione i can buy off alie is ~60 dollars for 1L, final price.

      can you substitute geometry structure to provide “softness”.

      Not really, I’ll need the squishiness on the walls, which will be 1.0-1.3mm thick