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A few years ago, I went to a yard sale and bought a set of auxiliary camera lenses, which included a telephoto lens and a wide-angle lens. Unfortunately, I didn’t actually own the Canon AF35M camera they were designed for, so I was never able to use them; attempts to sell the lenses on Nextdoor and Craigslist also failed. Recently I thought to take apart the lenses, and found that they were of constructed of interchangeable parts — the only differences between the two were the length of the lens tube, and of course the lens elements themselves. (The featured…
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Summary A very good material for making ingot molds is a 2:1 mixture of sand and clay This preparation is inexpensive, heat-resistant, does not require firing, and can be recycled Molds are formed by pressing 3D-printed patterns into a block of sand-clay Material In a blog post from 2 years ago, I wrote that “I simply mixed dirt with enough sand to prevent cracking and formed it into very simple molds that by virtue of their porosity were really temperature-resistant.” Since then I’ve done some more experimentation, and found that for rough molds, like those for ingots, the ideal …
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Summary I performed various tests on my DIY greensand, both to evaluate the tests’ reliability, and also the sand’s characteristics A microscope showed that my sand was angular and had a wide range of particle sizes The tensile strength test showed my sand was much weaker than industrially-used greensands. After refining my procedure, I was able to get moderately reliable results The compactability test showed that my sand had a higher unrammed density than industry sands, and gave very reliable results. The shatter test showed that my sand was about as tough as industrial sands, and gave reliable results. Introduction…
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Summary Through trial and error, I found the print settings that allow very fine sieves to be 3D-printed effectively. I also devised formulas for determining the appropriate infill percentage and thickness of such sieves. Introduction I recently found the need to sift store-bought sand to separate out the finer particles, with a targeted particle size of <0.4–0.5 mm (< 35–40 mesh). I considered using a kitchen sieve or a piece of window-screen, but found that they both had a hole size of about 1.5 mm (14 mesh), making them too coarse for my purposes. Since I couldn’t find any other…
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Abstract My goal was to measure the resistance of a dilute solution using tools available to me, and relate it to the solution’s concentration. A resistor was wired in series with the solution, and a DC power supply and a multimeter were used to measure the relative changes in input voltage and voltage across the resistor. This allowed the solution’s resistance to be calculated. I found a strong linear relationship between calculated resistance, and solution concentration. Introduction I was recently doing some more experiments with clay, which involved rinsing dissolved salts from a clay-water slurry. I wanted some way of…
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Are you working on a project consisting of FEM simulations done in FreeCAD? Are you using trial-and-error to converge your models? Or perhaps just running simulations on variations of the same basic geometry? Are you getting brain damage from the tedious and repetitive work of setting up simulations, and then babysitting them as they run??!! Well — fret no more! Introducing: an Automatic FreeCAD FEM Library! It contains functions designed to run without user input, almost as though it’s intelligent… but artificially. Using this library is free for one month, and then you’ll be automatically charged our monthly subscription fee…
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Summary I wanted a filter paper, made from household materials, that could filter out clay particles. Printer paper and notebook paper fulfilled this purpose, but passed water very slowly I found that by soaking paper in vinegar to remove their calcium carbonate filler, they would pass water more freely. Requirements for Filter Paper I recently needed to filter water out of a clay slurry for one of my projects. Since laboratory filter-paper wasn’t available, I had to try some common household filtration materials. In Chemical Manipulation, Michael Faraday writes, 487. […] Unsized paper, cloth, flannel, tow, sponge, sand, pulverized …
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Introduction An essential idea in finite element modelling (FEM) is convergence, the idea that as you make the simulation more and more lifelike, its results will converge to the real-life stress state. In most simulations, which mainly use single-point or rigid-body constraints, the main variable that must be converged is element size: as you make the elements smaller and smaller, the simulation will become truer and truer to reality. In this case, the procedure to obtain convergence is fairly simple: run successive simulations reducing the element size each time — for example, by halving it until the results — …
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With only a center punch and drill press, it can be very difficult to drill small, straight holes. Though medium-sized drills can self-center parts by shifting them around till the center-punch mark is exactly aligned with the spindle, smaller drills tend to just deflect and drill an angled hole. To overcome this, a short, stiff “spot drill” is used before drilling to create a new divot, exactly aligned with the spindle, obliterating the old center-punch divot and taking out any misalignment it might have had. Locating large holes accurately can also be difficult, since the large chisel-shaped tip of the…
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In Which I Am Nerd Sniped Some time in late 2024, I overheard a classmate talking about anodizing aluminium, for the purpose of laser-engraving it. They were interested in how it might be done at home. I understood the concept — using electricity to grow a thick oxide layer — and I wondered if it could be done with household chemicals. Of course, I had to try it myself, so I pursued the project on and off for the next few months. Introduction Aluminium is an incredibly reactive metal, but its oxide is inert and durable. The thin layer of…
Category: Random Projects
Random projects that I do to improve my life, try out an interesting new technology, learn a new skill, etc.
