Where do you stand on one of the eternal questions of metalwork: brazing, or welding? As your Hackaday writer, and the daughter of a blacksmith, it’s very much on the welding side here. Brazed joints can come apart too easily, which is why in the territory this is being written in at least, they are not permitted for the yearly vehicle roadworthiness test. If you’ve ever had to remove a brazed-on patch with an angle grinder, you’ll know which one you’d trust in a crisis.
What if the metal in question is aluminum? [George Graves] sends us a link to a forum discussion on the subject from a few years ago, and to a YouTube video which we’ve embedded below the break. Miracle brazing rods claim astounding toughness, but the world divides into those who favour TIG’s strength versus those who point to brazing’s penetration far between the surfaces of the metal to be joined. Having experimented with them a while back, we’ll admit that it’s true that aluminum brazing rods join broken parts impressively well. But yet again you won’t see this Hackaday writer riding a bike that wasn’t welded with the trusty TIG torch.
Take a look at the video, and see what you think. Even if it’s not a joint you’d stake your life on it’s still a technique that’s a useful addition to your workshop arsenal.
Whichever side you stand on brazing, please feel free to duke it out in the comments. Meanwhile there remains the important question of whether this al-oo-min-um stuff they’re talking about is as good as al-you-minnie-um.
[Mike] had a bunch of disused fitness machines lying around. Being a skilled welder, he decided to take them apart and put them back together in the shape of a belt grinder.
In particular, [Mike] is reusing the height-adjustment guide rail of an old workout bench to build the adjustable frame that holds the sanding belt. A powerful DC motor including a flywheel was scavenged from one treadmill, the speed controller came from another. [Mike] won’t miss the workout bench: Once you’re welding a piece of steel tube dead-center on a flywheel, as happened for the grinder’s drive wheel, you may call yourself a man (or woman) of steel.
The finished frame received a nice paint job, a little switching cabinet, proper running wheels and, of course, a sanding belt. Despite all recycling efforts, about 80 bucks went into the project, which is still a good deal for a rock-solid, variable-speed belt grinder.
Apparently, disused fitness devices make an ideal framework to build your own tools: Strong metal frames, plentiful adjustment guides, and strong treadmill motors. Let us know how you put old steel to good use in the comments and enjoy [Mike’s] build documentation video below!
It wasn’t the first time his group had worked together on something a little different, such as a robot that can deploy an antenna by climbing poles. However, this one had a time limit and they ended up trying to fit it all in the week before the race.
They had a pretty good design. [ITMAN496] had modeled the entire frame in SketchUp and even did physics simulations to get the steering just right. However, the best laid plans of mice and men often don’t fully take into account just how hard it is to get the motor drivers they bought working.
In the end, what they really needed was time to test. The setscrews couldn’t hold the motor on the shaft, the electronics needed debugging, and one of the belts was too long. The design was solid, but without time to percussively maintain the last bugs out of the system, it just wasn’t going to run.
[ITMAN496] is taking this lesson properly; he’s already planning for next year’s run, but this time he’ll have time to test. We must commend him — the build under these time constraints was still impressive. Even more so that he took the time to document everything while it was happening, and to share the story of shortfall after the fact. We’re always on the hunt for documented fails (the best way to really learn something).
Fearless makers are conquering ever more fields of engineering and science, finding out that curiosity and common sense is all it takes to tackle any DIY project. Great things can be accomplished, and nothing is rocket science. Except for rocket science of course, and we’re not afraid of that either. Soldering, welding, 3D printing, and the fine art of laminating composites are skills that cannot be unlearned once mastered. Unfortunately, neither can the long-term damage caused by fumes, toxic gasses and heavy metals. Take a moment, read the material safety datasheets, and incorporate the following, simple practices and gears into your projects.
Simple, Yet Effective
For tackling vapors, fumes, and flying bits, there are a few simple pieces of safety equipment that no maker should be without. This is the bare minimum when it comes to the mentioned hazards.
A respiratory mask protects your lungs from fine dust and fumes. Simple, mechanical filters made from non-woven fabrics are ideal sanding wood or drywall. There are dedicated painting masks and multi-purpose respirators, typically with layers of active carbon filter material, that also pull out some volatiles. Ideally, you go for a NIOSH approved respirator, which are classified by their oil resistance (N = nope, R = resistant, P = proof) and by the percentage of airborne particles they are capable of extracting (95 = 95%, 99 = 99%, 100 = 99.98 %). A NIOSH P100 respirator is oil proof and removes 99.98% of particulates if worn right. Yet, be aware that they’re just filters. Some volatiles will still pass right through them.
Even if you’re not afraid of getting your hands dirty in the workshop, consider wearing adequate gloves when working with substances that contain solvents, heavy metals or volatile organic compounds. Certain toxic volatiles have no problem entering your bloodstream through your skin, and thin protection gloves stop them reliably.
For fine work with resins or other chemicals, or for cleaning SLA 3D prints, go for nitrile gloves, as shown to the right. Nitrile gloves can also protect from incidental contact with stronger solvents like dichloromethane, but for extended contact with aggressive chemicals, consult a glove selection guide like this one or this one.
Gloves also prevent fine dusts, especially from carbon and glass fiber compounds, from causing skin irritations while sanding of milling. A pair of tough textile gloves will do here. Nevertheless, lathes and heavier drill presses yield a higher risk of injury when operated with loose gloves than without. It’s a compromise.
There’s an acute danger of putting your eyes out when working with live lasers without filter glasses — or while welding without a welding mask. Nobody would do this, right? Also, grinding wheels, angle grinders, and CNC machines will sporadically send dangerous projectiles their way. Besides that, long-term exposure to fine dusts, fumes and gasses can irritate your eyes and cause inflammations. They also provide easy access to your bloodstream, which is less romantic than it sounds within a cloud of toxic vapors. Just like everything else, safety goggles are standardized, but best maker-practice is keeping a pair of closed goggles and a pair of comfortable open ones. The former helps you out when dealing with strong chemicals (and shattering grinding wheels), and the latter increases the chance that you’re wearing at least something.
The Open Window
Be it while laser cutting, soldering, 3D printing or when working with organic solvents, make sure it’s happening in a well-ventilated area. The simplest and most effective way to reduce the parts per million (ppm) concentration of fumes and vapors is still an open window.
Taking your project outdoors can be even better. Professional work environments feature air cleaning systems and industrial grade protective gear, but workshops set up in poorly ventilated basements, garages or bunkers quickly saturate with toxic fumes and gasses. For the hobbyist, some activities are better done outside, where fumes and vapors dilute quickly.
Our Favorite Fumes
Some of our favorite activities come with hazards we should be aware of. The smell of burnt plastic and molten solder may ignite your creative genius, but the toxicity of these fumes shouldn’t be underestimated either. There are a few simple measurements you can take to minimize your exposure to hazardous fumes, dusts and vapors when working with your favorite tools.
Vent. Professional laser cutters feature external ventilation systems and active carbon filters, cheap ones often don’t have a ventilation exhaust. Retrofitting an air cleaning system to the latter is affordable and will pay itself off every second you’re not inhaling plastic fumes.
Despite ventilation, there are materials you don’t want to place inside a laser cutter. Among them are ABS (releases hydrocyanic acid), Polycarbonate (releases benzene), and PVC (releases Lucifer from hell hydrochloric acid). Some of these fumes are also hazardous to your laser optics, effectively limiting the harm that can be done here. Avoid unknown plastics or find out what they are, research new materials, and if you’re laser cutting sheet metal, head down to the welding section of this post.
Desktop?On the one hand, if you’re not using your 3D printer too often, and it probably doesn’t earn its footprint on your desk, on the other hand, if you use it every day, you will certainly want to install the noisy thing far away from your workplace. PLA and PETG are often recommended as a less emissive and practically harmless alternative to ABS and Polycarbonate. But unless you want to stick to natural PLA, you’ll be sitting in a cloud of ultrafine particles and gasses emitted while either the print material itself, additives or colorants decompose during printing. ABS emits hydrocyanic acid and styrene fumes when heated, PC emits benzene, and some PETGs and Nylons contain additives with evenly potentially hazardous decomposition products. Don’t worry – there’s virtually no acute danger that these fumes will fell you instantly – but with continuous exposure in a desktop environment, long-term effects can be at least expected.
If used right, SLA printers can be less emissive than FDM printers. Yet it all depends on the resin. Most stock and third-party resins for 3D printing use are just fine, but on the hunt for photopolymers, look for the zero VOC kinds (less than 5 g/l volatile organic compounds). In case you’re wondering, some (not all) photopolymers indeed contain homeopathic doses of the toxic heavy metal antimony in their photoinitiator. As a trace amount of a trace amount that isn’t released during normal use, it’s certainly the least of your problems. Uncured resins are irritating to the skin, so nitrile gloves for the cleanup and post-curing are the way to go here.
Open a window and get a solder fume extractor. Regular solder contains lead, and heating it up produces lead oxide fumes, which yields both short term and long term effects on your health. If you find yourself soldering a lot, a solder fume extractor will pays for itself and save you some headache, one of the common symptoms of lead oxide poisoning. Too costly? It’s just a bunch of fans and an active carbon filter pad, build your own!
Female hackers should mind that increased lead exposure is also linked to infertility, birth defects, and other reproductive harm. Consider lead-free solder as an alternative. Young hackers, and those who guide them, should be aware that even small amounts of lead can affect brain development. It’s better to complete the brains of your first robot lead-free. If you’ve ever had the pleasure of seeing experienced solder-instructors like Mitch Altman at work, you’ll notice that he takes special care to make sure all used materials are lead-free.
You probably prefer using solder wire with flux cores. In presence of lead, rosin-based flux is certainly the least of your problems, but it may cause irritations and yield long-term problems including asthma and dermatitis. Need a snack while you hack? Wash your hands before to avoid ingestion of lead and flux.
Avoid cadmium. Most of what’s true for soldering is also true for brazing. Yet, some silver solder alloys additionally contain cadmium. Cadmium is a toxic heavy metal that can actually knock a naive user out, so opt for zinc or nickel alloys instead.
Welding And Plasma Cutting
Ideally done outside. Electrowelders, TIG welding units, and plasma-torches have become cheap, and it’s easier to learn than most think. Welding is also an activity that emits plenty of toxic fumes and gasses into midair. Inhaling zinc oxide and magnesium oxide fumes, which emanate from galvanized steel during welding, can cause an illness known as metal fume fever. A respirator helps, although besides toxic fumes, also gasses are emitted from the filler material, other welding consumables and impurities (e.g. paint) on the welded material. Long-term exposure to welding fumes is known to cause lung cancer and a number of other diseases like asthma and pneumonia. Needless to say that welding without a welding mask will affect your eyesight, but good ventilation is equally important. For the hobbyist, all this is ideally done outdoors.
Sanding And Milling
Wear a respirator. Other than gasses and vapors, particulates from sanding or subtractive machining can easily be brought under control by wearing a simple respiratory mask. Additional safety goggles protect your eyes from acute injury and irritating dusts, especially from materials like glass fibers (e.g. from FR4 PCBs), and carbon fiber compounds.
There’s nothing as satisfying as using the correct solvent or resin for a given application. If you’ve noticed that a few of them smell funny, that’s your clue to check the backside of the container and do some reading.
Acetone, Turpentine, Naphtha, “Brush Cleaner”
Open a window and wear gloves. Even if you ignore all safety instructions on the container, you’ll probably automatically open a window when working with turpentine or acetone. The latter isn’t considered carcinogenic (anymore), but skin contact with the strong solvent as well as inhalation of its vapors can cause irritations. Turpentine, on the other hand, also commonly used as a brush cleaner, is indeed considered toxic, and its fumes will typically cause a headache, reminding you to take action and get some fresh air. It’s worth mentioning that there are a number of turpentine-replacements, including naphtha-based brush cleaners, that can be carcinogenic as well.
Avoid it if you can. Beyond the usual suspects, one of the more controversial solvents is dichloromethane. It’s highly volatile can even enter one’s bloodstream not only through vapor inhalation, but also through skin contact. In the EU, it’s banned as toxic and carcinogenic, despite the absence of useful replacements for applications like paint-strippers. It’s commonly used as such in the US and in other parts of the world, where it’s likely to be marked as toxic. It’s toxicity mostly affects workers who are exposed to the solvent unprotected and on a regular basis, rather than the hobbyist who uses it once.
However, it’s often suggested (e.g. here and here) to use dichloromethane to mix polycarbonate slurry as a means of improved build plate adhesion in desktop 3D printers, or to use dichloromethane to smooth prints from polycarbonate. If you plan to do this on a regular basis, maybe even in a desktop environment without further safety considerations like a self-contained breathing apparatus and chemical gloves, you might be facing a similar destiny as more than 14 bathtub refinishers, who the OSHA reports have died since 2000 from repeated dichloromethane exposure.
Use epoxy instead. Polyesters and other resins that contain volatile organic compounds (VOC), in particular styrene. If and how much styrene is actually carcinogenic is not entirely clear, but excessive exposure definitely leads to dizziness, with more acute risks when using heavy machinery or conducting vehicles afterward. Think twice if your project really requires polyester resin – epoxy may be more expensive, but it delivers a better mechanical performance and is far less costly in terms of your health.
Toxic Heavy Metals
Be aware and take care. Toxic heavy metals can be found both in solder and brazing fumes (mostly lead and cadmium), welding fumes (arsenic, chromium), in some photopolymers for 3D (and 2D) printing (antimony), and of course, in mercury switches and antique thermometers. If absorbed by your body, toxic heavy metals have the tendency to accumulate over an entire lifetime. They typically bind to certain organs or vital systems, where they may concentrate to toxic levels over time, causing various diseases from cancer over nervous disorders to diabetes.
Their toxicity depends a lot on their dose and application, as their presence in solder, piping, food packing and dental fillings shows. Still, avoid naive, repetitive exposure. This can be as simple as washing your hands after soldering, or wearing respiratory protection when welding or during other activities that bring you in contact with fumes and dust that contain heavy metals.
If you made it so far, a bit of soldering won’t knock you out, a bit of 3D printing won’t harm, and a bit of laser cutting won’t hurt. That’s not what this post is about. We’re not made of glass! Yet, the maker movement is going places, and there’s a growing gray zone where occasional fun projects develop into production-scale undertakings, and where art projects become monumental life works. Repeated and intense exposure to some hazards is a very different game than a little tinkering once in a while, and it really doesn’t take much to prevent long-term consequences. I’m sure many of our readers have great advice to add to this, be it from professional experience with occupational safety standards, or their own implementations to tackling solder fumes. Let us know in the comments!
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