29' #video by #Malawey on why engineering labs need rags. I didn’t know that there were auger-based PID-controlled charcoal barbecue grills with calibrated thermostats. He recommends diaper cloth for many jobs because it’s lint-free. #toread
on 02025-09-29#video by #Malawey on #manufacturing with #8020 and similar aluminum T-nut extrusions. He prefers the Automation Direct brand. 30×30mm has pricing of US$15/meter (M6 fasteners ideal, or M8 for the end holes, 9mm groove depth), 20×20 US$8/m (M5 fasteners ideal, or M6 for the end holes, 7mm groove depth), 35mm DIN rail US$5.20. He cuts them with wood-cutting blades on wood saws, although his "wood blade" looks like it has a brazed-on insert on each tooth, presumably tungsten carbide, and it appears to say “CARBIDE TEETH / DIENTES DE CARBURO / DENTS DE CARBURE”, so it could probably cut concrete. He recommends putting some wax on the blade to make a cleaner cut, by cutting a bar of wax together with the aluminum. He reports that it is also possible to get a clean cut on cut magnesium #materials with a saw this way. He warns that “V-groove” extrusions are needed for rolling V-groove wheels on. Sometimes your screws contact the bottoms of the grooves because they’re too long, which can be remedied with a thick washer. For wheels he recommends #3D-printing a bracket to hold a rollerblade wheel. He spends several minutes demonstrting how to use SolidWorks to design such things by pretending they’re weldments.
on 02025-09-29#Malawey #video #toread on different kinds of tape
on 02024-09-05#Malawey #video #toread on reproducible battery energy experiments
on 02024-09-01another #Malawey #manufacturing #video. JB-welding coaxial things inside a brass sleeve, which failed between 60 and 80 “inch-pounds” (7–9 N m) maybe because he didn’t let it set long enough. He says you can bond silicone to already-cured silicone (like a silicone sheet bought from the store) with full strength, so you can use it to jugaad things together, like an insulating pad he put on his magnetic-stirring hotplate, and an extra finger grip for his soldering iron, and his custom soldering rack with a silicone tube inside a steel tube. You can mix white silicone with any oil paint. Demonstrates how he can reuse a polyethylene cup after mixing white silicone with blue pigment in it. Demonstrates melting hot glue (EVA?) with a heat gun to make a light diffuser over a LED. Describes which plastics are annoyingly glue-resistant. Talks about Liquid Nails and similar construction adhesives, which he says are basically pasty wood glue (I think that’s chemically false) because it’s sandable and paintable, stronger than wood, water-resistant, shrinks when it dries, and washes off with water when wet (water cleanup). Then points out that non-water-soluble construction adhesives are totally different. He says the pasty stuff is better at filling gaps and so sometimes stronger in practice, though weaker in theory. Explains that J-B Weld does make something of a chemical bond with metal, not a purely mechanical one. Peels cured J-B Weld off a bicycle inner tube segment. Shows nylon resisting J-B Weld adhesion. Demonstrates how J-B Weld can be popped off ABS and soft polyurethane with some force. Taps 30-hour cured J-B Weld with a combined drill and M4 tap. He 3-D printed a PVC cement can lid grabbing tool! Then he gets off talking about Bondo and epoxy resin composites and whatnot. Demonstrates soaking nylon webbing in epoxy to somewhat stick it to other nylon webbing. Recommends E6000 or a similar contact cement like Weldwood for sticking to things like smooth, shiny polyethylene, but it still won’t withstand any substantial amount of tension or peeling. He did manage to glue nylon webbing by impregnating it heavily with black ABS cement! The adhesive he tried on EVA foam (Titebond PVC trim adhesive and sealant) didn’t stick, and between two sheets of nylon it didn’t even set.
on 02024-09-01#Malawey #video on #precision #mechanisms with #3D-printing: “Borrow a Tolerance!” Lots of wisdom about mechanical engineering and which industrial #manufacturing processes have which drawbacks. He shows a 3-D printed collet as one example of a non-borrowed good tolerance. Demonstrates some 3-D printed springs in I guess ABS, but says you can “borrow a [precision] spring rate” from a spring-steel binder clip, which also doesn’t creep at “any temperature a human can survive”. Borrowing smoothness and toughness from HDPE tubing (from water systems) to make hinges; he sharpens it in a pencil sharpener to get it to go through his #print-in-place hinges more easily. His print-in-place approach has support material between parallel horizontal layers which must be broken free with a spatula or hammer.
on 02024-08-27