The world of glues is wide and varied, and it pays to use the right glue for the job. When [Eric] needed to stick a wide and flat 3D printed mount onto the back of a PCB that had been weatherproofed with an uneven epoxy coating, he needed a gap-filling adhesive that would bond to both surfaces. It seemed like a job for the hot glue gun, but the surface was a bit larger than [Eric] was comfortable using with hot glue for. The larger the surface to be glued, the harder it is to do the whole thing before hot glue cools too much to bond properly.
What [Eric] really wanted to use was a high quality two-part epoxy that he already had on hand, but the stuff was too runny to work properly for this application. His solution was to thicken it with a thixotropic filler, which yields a mixture that is akin to peanut butter: sticky, easily spread to where it’s needed, but otherwise stays in place without dripping or sagging and doesn’t affect bonding.
Common thixotropic fillers include ground silica or plastic fibers, but [Eric]’s choice was wood flour. Wood flour is really just very fine sawdust, and easily obtained from the bag on his orbital sander. Simply mix up a batch of thin two-part epoxy and stir in some wood flour until the sticky mixture holds its shape. Apply as needed, and allow it to cure.
Thanks to this, [Eric] was able to securely glue a 3D printed pad to the back of his animated LED snowflakes to help mount them in tricky spots. Whether for small projects or huge installations, LEDs, PCBs, and snowflakes are a good combination.
Are all cheap multimeter leads similarly useless? Not necessarily. [nop head] also purchased the set pictured here. It has no attachments, but was a much better design and had a resistance of only 64 milliohms. Not great, but certainly serviceable and clearly a much better value than the other set.
The belts used were common steel-core polyurethane GT2 belts, and the clamp design uses a short segment of the same belt to lock together both ends, as shown above. It’s a simple and effective design, but one that isn’t sustainable in the longer term.
It all began when the kids were taken to a local fab lab at the École Polytechnique and made some laser-cut napkin holders from plywood for personal use. Later, they decided to design, manufacture, and sell them at the Ottawa Maker Faire. Money for the plywood came from piggy banks, 23 different designs made the cut, and a total of 103 rings were made. A display board and signs made from reclaimed materials rounded out the whole set.
