The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • 3D Printed Smashed Glass Coasters: Being Epoxy-Tight

    Each of the glass fragments in a 3D printed coaster sits atop a metallized paper reflector in its own recess and gets covered with epoxy:

    Printed Coasters - epoxy fill
    Printed Coasters – epoxy fill

    That’s an early printed coaster with the epoxy pool covering the entire surface. Putting a rim around each fragment to form separate pools works better.

    Assuming I do a tidy job of filling the recesses, this process worked exactly as you’d expect until I printed a coaster with blue PETG-CF filament:

    Printed Coaster - Set C - oblique
    Printed Coaster – Set C – oblique

    Other than a slightly ragged cork layer motivating me to make the cork slightly smaller and use a fixture to align it properly, the coaster looks reasonably good. However, a close inspection shows all the epoxy pools are slightly recessed below their rims.

    It turns out printing PETG-CF with an extrusion multiplier of 0.8, which I figured based on fitting threaded parts together, doesn’t fuse the threads into an epoxy-tight surface:

    Printed Coasters - PETG-CF leakage - footprint
    Printed Coasters – PETG-CF leakage – footprint

    Fortunately, I’d been working on a silicone mat that could take a joke. I managed to move the coaster to a plastic sheet and refill the drained pools, although they continued to drain while curing.

    After the epoxy cured to a rubbery texture, I scraped off the meniscus around the perimeter of the coaster, but the bottom shows it cured in a pool of its own making:

    Printed Coasters - PETG-CF leakage
    Printed Coasters – PETG-CF leakage

    The cork conceals the evidence and the result looks good enough for my simple needs:

    Smashed Glass 3D Printed Coaster - Set C - in use
    Smashed Glass 3D Printed Coaster – Set C – in use

    Memo to self: Use the correct filament preset for the job!