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

  • Humidifier Lid Hinges

    The humidifier that Came With The House™ had a lid with two broken plastic hinges that I figured I could never replace, but while cleaning out the fuzz for the upcoming season I found one missing piece stuck inside the lid. Given a hint, I glued it back in place:

    Humidifier Hinge - outlined
    Humidifier Hinge – outlined

    There’s a strip of duct tape around the outside holding the fragment in place while the adhesive cured.

    A manual curve fit to the image in Inkscape produced the red outline, which gets saved as a plain SVG and fed into OpenSCAD to create a solid model:

    Humidifier Hinge - solid model
    Humidifier Hinge – solid model

    The cylinder doesn’t exactly fit the end of the hinge, but it’s close enough. The straightforward OpenSCAD code making that happen:

    // Humidfier Hinge Replacement
    // Ed Nisley KE4ZNU
    // 2024-10-20
    
    HingeThick = 10.0;
    PinLength = 10.0;
    
    ScrewOD = 2.0;
    
    NumSides = 2*3*4;
    Protrusion = 0.1;
    
    difference() {
        union() {
            translate([0,0,HingeThick])
                cylinder(d=6.0,h=PinLength,$fn=NumSides);
    
            linear_extrude(height=10.0,convexity=5)
                translate([-3.1,-8.0])
                    import("Humidifier Hinge - ouline.svg");
        }
    
        cylinder(d=ScrewOD,h=4*(HingeThick + PinLength),center=true,$fn=8);
    }
    

    The pin has a hole for a M2 screw, but contemplation of the broken pieces suggested the pin wasn’t the weakest link, which later experience confirmed.

    Figuring I’d need only one hinge, I made a spare for fitting:

    Humidifier hinge - on platform
    Humidifier hinge – on platform

    The unmodified part fit just about perfectly, whereupon a completely ad-hoc fixture involving a pair of laser-cut MDF slabs, a craft stick epoxy mixer, and more duct tape held it in place while the adhesive cured:

    Humidifier hinge - fixturing
    Humidifier hinge – fixturing

    The hinge pin turned out to be half a millimeter too long, which is easily fixed, and it worked fine:

    Humidifier hinge - installed
    Humidifier hinge – installed

    That’s more duct tape wrapped around the perimeter to hold the pieces in place, should it break again.

    Which, I regret to report, occurred on the way up the stairs from the Basement Shop™ when the lid slipped from my grasp, fell away from the rest of the humidifer’s top panel, and jammed open:

    Humidifier hinge - break
    Humidifier hinge – break

    The PETG-CF part held together, the adhesive remained bonded to both pieces, but the original plastic fractured just below the joint. A closer look from the other side shows the break:

    Humidifier hinge - break detail
    Humidifier hinge – break detail

    The other hinge broke about where it did before.

    So the humidifier remains in service with the lid in status quo ante and a small bag inside holding the fragments for the next return to the shop.

    Drat!