A Word About Your Safety When Building at Home
All of us EAA’ers appreciate a new design on the ramp or an existing airplane built to amazing standards of workmanship. A Lindy award airplane isn’t just about exacting standards or attention to detail, it’s also about doing things in a safe manner and we are talking about shop safety. Ever see a builder or mechanic missing a finger or thumb? Decades ago, it was normal to see someone with a missing or disfigured digit on a hand when working around airplanes, especially commercial ones. Nowadays it’s pretty important to have all of your fingers to type with and it’s pretty tough to Tweet on a cell phone when missing one’s thumbs. Think you won’t do something like this? Ask someone who did this if he thought he would ever hurt himself and they will always say “no”. Is that part or plane assembly worth injury or permanent disfigurement? Naturally all of us would say no right up to the moment that we make that silly mistake. You won't see anything written in Sport Aviation, yet as the homebuilt movement in EAA has exploded in the last several decades we still hear horror stories about accidents and incidents in the garage ranging from hand impaling's to fires that would make an OSHA inspector wince out in the aerospace industry.
There are a lot of RV builders who have drilled a rivet hole and the drill bit ended up going through their hand on the other side. This sounds stupid, but it happens every day even at the Big Iron makers in Wichita and Seattle. Put a head on a rivet gun without having the retaining spring attached right? It might not come off on the first couple of holes as you use it against metal, but when it does its going to leave a big mark on your project or maybe on your forehead or worse, on the person bucking the rivets for you. And that might be your significant other, partner, or your kid maybe?
Powered equipment can really make the job faster and quicker and not a lot of us would ever give up something like their pneumatic C squeezer especially on the big sizes of rivets. But pneumatic rivet squeezers and pneumatic and hydraulic presses are examples of stored energy that when used incorrectly or inconsistently create pinch points for fingers and skin easily cutting or piercing them. Get a shaft going anyway other than straight down in even in a small hydraulic press and the piece can fly out of it like a spring hitting you. Bending something without capturing it correctly can easily result in a black eye or worse as it springs back. Sheet metal shears are pretty popular for some folks who cut a lot of metal, but some folks consistently use them on the wrong materials, or on thicker materials they weren't designed for and they can break pretty violently when the cutting jaws fail. Even very small hydraulic forming presses or air driven hammers won’t even slow down if your fingers are in them when you pull the lever or push the button so take a moment for extra care.
Any rotary driven tool, such as hand drills will cut skin pretty easily, but using cotton, leather, or even latex gloves thinking that it will prevent this is a recipe for disaster. Drill bits will grab any loose clothing, wires, cords, gloves, and hair. Ever seen long hair wound tight in a drill bit? I have seen it rip the hair out by the roots "scalping" the unfortunate victim so it is imperative that hair is under either a hat or a hair net and away from the tool any time you are using a drill press or any hand drill. Wedding rings will get caught as well and can "divorce" your finger your finger from the rest of you. Oh, and a palm drill is too small to do this? No, it can and will! Long sleeve shirts and other clothing? Yup, them too, so if you have to use a glove always use one of the new driller’s glove (tight, form fitted metallic safety gloves available at safety equipment stores) that keeps your skin from the bit and chuck and stops cuts from chips or wear nothing and simply keep your fingers away which is the safe way most of us do it. Don't forget to use simple pliers to remove the wound up spring-like chips around chips from drill bits and never use your fingers. They are like razor's!
Using your equipment incorrectly for the job is something that some builders like to boast about as a feat of ingenuity and higher intelligence. Goody! We worked around a problem and figured out a solution, right? An example of this is making large diameter holes using a trepanning tool in a hand drill (a sure way to hurt yourself) or using hole saws missing the center locating drill is simply silly, will damage your work piece, and can mess up wrists and fingers pretty quickly resulting in a trip to the local emergent care facility. They are made to be used in machine tools and not your hands. That's not a solution to anything. Using drill presses as milling machines, a task they are not designed for is a fast way to ruin a light duty drill press and hurt yourself in the process as well. Need a metal lathe and are eyeing your wood lathe? Don’t try cutting metal on a wood lathe as you simply can’t hold onto a hand bit on a lathe fence and get away with it even on soft metals like aluminum. If you need precision pieces made, buy the right tools (used small lathes and mills can be had pretty cheaply) or simply draw them out and have them made at a multitude of internet based machine shops who will take your emailed drawing and overnight the part to you UPS, or go to the local machine shop and have them made by pros.
Are you using electric hand tools that have trigger locks that keep the tool running without the operator gripping the trigger? Disable them! When the drill sticks in the hole or the saw hangs in the sheet, it will keep running once you let go and the tool will continue to run. If it’s a drill it will spin and wind up the extension cord or air hose and it will hurt you if you try and wrestle it yourself or cost you in damage to yourself or your project as it whips around your shop. No hand tool that you own should ever run once you release it. Powered hand saws are in this same category as most have a safety to that prevents depressing the trigger but old ones have trigger-on locks which hurt the inexperienced beginner more than they should. Table saws injure and maim more people in the U.S. than any other tool is another story altogether as, though simple to use, are absolutely unforgiving when used incorrectly. If you are new to using one, please ask for help from someone who is experienced in using a table saw as finger and hand amputations happen every single day in the U.S. and are easily preventable.
This brings us to guards and shields on power tools. Ok, we know all about how dangerous table saws can be, but taking guards off even simple tools like the good ‘ol band saw can also mean a trip to the doctor for stitches. Remember that they use band saws at the butcher’s shop for meat so a little respect for the Delta is a good thing. Likewise grinders, belt sanders, and disk sanders all have work rests that are meant to be within a 1/8th of an inch from the grinding surface to prevent the work slipping between the wheel or belt and the work rest and jamming the motor or ejecting it violently. This can also break a grinding wheel into pieces hurting fingers and blowing up into the eyes. At the least it will scare you pretty badly, but jamb a belt sander and tear a belt, the flap can grab the work or your fingers as it comes off and it’s going to hurt. Always keep the rests and fences properly adjusted on abrasive tools and never grind aluminum and other non-ferrous (non-steel) materials on grinding wheels. They will “load up” with melted material on the surface of the wheel, it will get hot, crack, and blow up on you. If the guards are adjusted correctly, they will contain most of this and it turns into a non-event. If not, it will be in your face. Remember too that grinding steel on a wheel will eject sparks that can start fires on carpet or rags just left around on the floor so keep flammable materials away from heat producing processes.
But what about the other tools that you use in the garage that are unsafe that you don’t normally see as unsafe? We all need an air supply and belt driven air compressors come to mind as the best way to generate air pressure. But a goodly number of used ones are missing the cage over the drive belt because we bought an old one used from a friend or at a garage sale. Imaging what might happen if your toddler is near it when it suddenly comes on and you will clearly see the belt driven air compressor with its pinch point belts and wheels in a new light. Resist the urge to buy that used treasure and go to the hardware store or on-line and buy a new one with all of the safety guards intact as a good compressor is something you will use the rest of your life.
Compressed air can be dangerous too as using an air gun nozzle without a pressure relief nozzle can force pressurized air directly to your skin. Blow over 60lbs of air over yourself with the nozzle too close to your skin and if there is a cut in your skin, air will go right into your finger or arm and form an air bubble just under your skin. Many times, you can massage this back out the hole in your skin, but if it’s big enough it can go into your circulatory system and cause an embolism in your lungs, heart, or brain. Then there is your eyes and ears which is self-explanatory so enough is said. Compressed air isn’t a toy its a tool so don’t point it at yourself or others.
Welders and Plasma Cutters.
There was a time when all we really had to work with at home for welding material together was an acetylene torch or an AC stick welder. A lot of aircraft structures that should have been made from aluminum were made instead out of light steel tubing because only the big boys could afford TIG setups. Today, a lot of us have TIG, MIG, AC/DC, oxy/acetylene, and plasma cutters in the shop as the prices have plummeted on all this equipment and they are much easier to use than ever before. But, welders like TIG sets are electrical in nature and shock hazards are possible when work isn’t grounded right, or you are not insulated right. Ever see someone weld while standing on wet surfaces and turn into the ground? Well it happens and the tingling is impressive. Ever seen someone weld with no gloves? You can turn into the ground and flash burns will result on the exposed skin as an arc welding process make the entire magnetic spectrum just like the sun. We all know what the burn feels like and we who have done this for any length of time usually smarten up pretty quickly and cover up. But we still see folks not using the right head gear when TIG welding thinking that just protecting the eyes is enough because there isn’t a lot of spatter coming from the weld and won't wear any face covering. This puts pin-point holes in the skin of the cheeks and forehead and a lot of infrared light that even SPF50 won't stop. Ever use sunglasses to tack something together thinking its only for a second or so? The weld itself can be over 4000 degrees and emit the entire light spectrum so this is simply foolish using Foster Grants from the dime store this way. Go buy an electronic welding helmet for fifty bucks and this risk simply goes away making you ask why you didn’t buy one a long time ago.
Have a plasma cutter? Man, they are cool! The prices have come down so much that they are becoming nearly standard equipment in most shops. Just have someone show you how to use it properly and remember that even though metals just seem to "evaporate" into the ether there is still hot slag getting blown around and the material will get pretty hot also so remember that a good pair of gloves and at least a cover-all is a requirement. Don't forget face shields. Also some materials are coated with oils or plastic films and you will get fumes and smoke as they burn off that you would not get using an old-fashioned saw or cutter so be cautious as different materials react differently when being cut with plasma.
It should surprise no one that good welding cable and leads are a necessity for electrical welding, but many times this just isn’t the case, especially on used systems that folks buy thinking that they are a bargain. When you do this a while you begin to notice that the weld puddles differently when you hold the electrode in different angles even though the work is flat. Check your connections for cable fatigue and tightness and many times this goes away. Also, on used systems, the cable might have been replaced at one time, but the cable gage is smaller than it’s supposed to be. Look up the model from the manufacturer and see what the cable gages and lengths are supposed to be when new as it’s not unusual for folks to make new leads especially ground leads that are much longer than they should be and thus need to be a bigger gauge size and sells it off that way to you. Also, make sure the electrical plug ground prong is there and works! You can be the ground in the wrong time, and it may not be that "tickle" that you might feel warning you. If you are older and have a pacemaker it could be fatal.
Do you have a fire extinguisher handy? Is it a tiny one from Walmart? It’s OK to have a smaller sized extinguisher, just have more than one of them and have them in two different places as it’s not funny to have the fire burning right by the extinguisher you need to put it out with but can’t reach because it’s by the fire. Never put the extinguisher right where you are welding. Remember the Quench tank or bucket of water? Old school, but it works every time especially when you need to put your hand or arm into it after an inadvertent burn which an extinguisher can't do. Second and third degree burns especially large ones are actually medical emergencies and need to be treated by professionals to avoid infections.
Composites and Fun with Chemicals Using Caution
With the new composite materials available today, the imagination can run wild in aircraft design and the use of these materials become mandatory when you simply can't form the surfaces that you need otherwise. Unfortunately, do not believe the siren song about how easy and simple it is to use composites and ignore that all of this is bonded together by resins and adhesives that are hazardous not to mention that you will be using a great deal of solvents and cleaners that are hazardous too when doing it. The sales people who write up your order or the salesmen at the counter at the store doesn't know much more than you about what is really in the paints or resins that they sell you so you have to educate yourself about what you are using beforehand. ASK for the material safety sheet about what you are buying, and they should be able to give you a copy.
Chemical absorption always happens when you are exposed to a chemical through respiratory, dermal, or ingestion through the mouth, but the effects are totally dependent on the dose you receive over time and how well the liver and kidneys can process it so many times the chemical exposure below a certain level each time is safe. But some chemicals are cumulative in exposure like lead and you always need to read the material data safety sheets about whatever material you are using as that is the only place any of us will ever learn about the bad sides of what we are using. Even if you read that you can drink it, repeated exposure to paints, epoxies, and solvents, is preventable and controllable and should always be kept at a minimum. Further, repeated exposure to resins, solvents, and adhesives is the fastest way to get sensitized to chemicals and a surprising number of airplane projects have ended up on E-bay because the builder becomes ill when he is anywhere near the chemicals he needed to work with. This can happen to you as well, so this means protecting yourself from chemical ingestion through the lungs, dermal contact through the skin, or by taking it inadvertently through the mouth. Most of the time its breathing that represents the highest risk for exposure like two- or three-part epoxies that require adequate ventilation to use and can cause nerve or lung damage if the part per million exposure exceeds certain levels. To work around these characteristics just requires some common sense: if the temperature outside is high enough, leave the garage door open with a fan running to blow fresh air inside. If you can’t do this, buy a fresh air pump, hose, and face mask drawing air from outside for the shop that slightly over-pressurizes the mask providing you will clean air that is good for the noggin. You also can use respirators. Respirators are simple to use, but understand that depending on the cartridge type, once its opened for use it can only be used for a certain period of time and then it becomes useless and CANNOT BE REUSED so don’t reuse them and buy enough to always have a fresh one when you need it. Also be aware that some people have diminished lung respiratory capacity and can’t use a respirator. To know if you can you can, undergo a simple test of wearing the mask and having your blood oxygen levels monitored at the doctor’s office or observed with someone other than you using an oxygen blood dosimeter on a finger to make sure that you are not asphyxiating yourself using it. Whatever method you use, if there are two of you working in the workspace you will need two units supplying fresh air or respirators and don’t get the idea that your kids who are younger than you doesn’t need a mask as well. Poisoning is an equal opportunity risk. Remember too to not get the idea of using compressed air as air from some pumps can be laced with oil and is toxic so beware at the thought of doing this. Shop air compressors should never be used as a source of breathing air.
Most adhesives and sealants are two part epoxies. They don't "dry" but cure instead in a chemical process. Most mix in equal proportions, or, in one-to-one proportions. Don't be fooled into adding more of the catalyst into the mix to make it cure faster as it will seriously reduce the strength and properties of the bond of the sealant to the base material. Just as well mixing too little catalyst with the resin and find out that it can take days to cure to its design strength. Usually, when this sort of thing happens with too much, at best it becomes weak over time and at worst cracks and flakes under load in the first year or so. Follow the directions and use sealants and adhesives that are within their "use by" dates which are printed on the tube or can. Don't use old stuff as it chemically degrades just sitting there. Also note that the hardener is a catalyzer and is quite acidic and you really need to make sure that the gloves you use will actually prevent skin contact as you can be burned quite easily by it. You can also get fumes as well so be sure to have adequate ventilation.
Latex gloves are not the sort of thing that a lot of folks think about when using chemicals but are essential in keeping yourself from getting poisoned. All skin is permeable and many solvents and catalysts that you will be using will readily go right through your skin leaving you with that funny taste in your mouth that you can’t describe. Fine, let’s go down to Harbor Freight and get latex gloves by the box full, but “whoa” first. Latex, of which some folks are allergic to, are great for keeping detergents or oils from the hands doing housework or working on an engine, but are next to useless with all of the ketone’s used for resins and the solvents for cleaning it up with. Nytrils? They work with acetone and alcohol just fine but will only withstand MPK for 15 minutes or so and will break down completely when used on many compounds. Solvex gloves are the proper ones to use (have a silver appearance) and will be good for about an hour or so and are readily available from safety supply stores. As for the cheap gloves available at the discount store you never know exactly what is real or just lettering on the box printed in some Third World country. How then do you know if a particular chemical will work with your gloves that you have? A simple and practical test is to take a glove and fill up a finger of the glove with the chemical and tie it off and time how long it takes for the chemical to leach through the glove. Record the time it begins to bleed through and just divide it by half and that is how long you should wear it in contact with that particular chemical. The longer the time the better. Double gloving? You can, just understand you should use the original number you came up with, just don’t double the time because you have on two gloves on now or you can get bit if you mess up the time. Be sure of what you have on hand, just don’t be foolish and use anything without checking first.
Most people don’t know about flash points and you won't hear about it at the paint store for some reason. This is the temperature where a chemical flashes off or evaporates from a liquid to a vapor. Higher flash point chemicals are safer to work with than ones with lower points and it’s pretty easy to get a fire going with kerosene at 563 degrees F, but much harder with simple isopropyl alcohol at 750 degrees F. Which one should you use? The one that you have to use to complete the work, but understand that you have to take measures to safely use chemicals even when there isn’t an open flame to start a fire as a hot motor or part can be an ignition source too. For instance, you can mess up and add too much catalyst and get a part smoking in the mold and it can catch on fire so you don't need an open flame to have a bad outcome so be careful! Be selective and make sure that you won’t need to use your fire insurance policy.
Everyone needs a degreaser. Citra-safe works about as well as a degreaser as MPK in the can from Home Depot does, but it can be used without gloves and won’t burn and stink. You should use the ketone when you don't want any residue left but why use this expensive chemical simply to clean parts if a safer and less expensive chemical is available? A wash tank full of Dawn dish washing detergent and hot water that can be poured down the sewer and costs pennies is even better. Wash in hot detergent, rinse in hot water, dry it, and nine out of ten times you will be good to go. Get in the habit of using the least hazardous chemicals first instead of going to the nuclear option first. Using denatured alcohol or paint thinner or acetone instead to get what you have to have clean enough is better than using MPK or many or the other ketones available at the hardware store. Its cheaper, safer, and smarter to dispose of refuse later thinking this way.
Eye wear is an important thing when using chemicals as accidents happen. Dust is one thing but get acetate adhesive in an eye and you are blind with no going back from it. Tight fitting safety glasses with foam edges to seal the eyes off work great are now pretty cheap and easy to get. Goggles of good quality that has room for glasses work for the optically challenged of us out here as well, but don’t think that you need safety glasses when just working with rotating tools, because simple acts such as hand sanding can drive particles up into your eyes just as well as a power sander might do.
Most of the time and depending on the type of material used and the stage of completed pieces in a kit, you may have a lot of dust issues from sanding and cutting. If it’s a scratch build one-off carbon airplane going on you will have a TON of dust. Dust from fiberglass is actually tiny glass particles and are very abrasive to the skin, eyes, and lungs. Carbon dust never breaks down in the lungs. Additionally, the resin dust is abrasive as well. Many builders buy tyvek suits that can be thrown away once they are contaminated. and tape the seams and cuffs shut to help with this. They come in several types and in five different sizes with zippers on the front. They can be bought at most auto paint stores and most safety supply companies by the gross. Now they aren’t cheap but are essential for many builders to keep the dust off of themselves. Another nearly essential device is to buy a large bag capacity electric dust filter of at least one horsepower. The cubic feet per minute of air that it can handle is large enough to capture most of the particulates being generated if the pickup hose are at the point of the sanding thus saving a lot work and keeping the shop/garage/house cleaner (and the wife or husband happier). These run about $350 at Grizzly.com and are worth their weight in gold.
Lastly, don’t eat anything around your project if there are chemicals around as well. Paints, adhesives, oils, solvents, and paint. What’s in your open containers will end up in your coffee cup eventually from the open air and what is on your fingers will end up on the potato chips that end up in your mouth: learn to keep and eat food where food belongs and things will surely taste a lot better.
Engine Hoists and Crane's
Everyone will eventually need to pick something heavy up sooner or later. It's a fact and our eye's always go to one of our automotive suppliers or Harbor Freight to get a cheap lift of some sort and even some that fold up to a pretty small package to store away. The typical hydraulic engine hoist can usually handle a ton or more in weight and can pivot in some close quarters... if your floor is flat, hard, and without deep grooves in it that catch wheels. Most shop floors or garages are concrete but take a minute and look at where you propose rolling this lift over and consider the size of the wheels. Bigger ones roll easier and can roll over smaller cracks easily, but never think you can roll it over dirt or gravel no matter the size of the wheels. Also, consider how much your load might swing on a rope or chain when moving this around the shop. Will your load slip off of the hoist, or can it swing into your new project that took months or years to assemble? Matter of fact, are you trying to have the mobile engine hoist lift and hold the engine or airplane assembly stationary for you somehow? Remember also that hoists with narrow wheel spacing are easy sometimes to topple when pushing from the sides so try not to push in the wrong directions while pulling on wrenches with the load suspended. Also make sure the balance point of your lift is BEHIND the center of the wheels or sure enough, the load will topple the whole hoist forwards onto the floor or onto you!
Now you want to use a chain lift or a come-along from a garage rafter. This is a BAD thing to do as most engineered trusses in houses are made from wood and they are NOT made to handle a load such as this from the bottom of the truss and are in tension holding up your roof. A 400 lb. load at a single point along it can easily overload one of these trusses which can crack while holding up your $20K engine, your airplane, and all the Christmas stuff up in the attic too. At the very least, put a 2X4 from the bottom of the truss to the floor close to the load and let it handle the load. At the best, buy a beam hoist on wheels on the floor instead as most of them will handle tons of load safely and only cost a bit more than the hydraulic engine hoist you were looking at before.
Space is something that none of us ever have enough of before we begin and as the project gets bigger, we always wish we have more of it. Typically, our workspace is a garage bay or many times in areas that are much smaller, so it is usually a space pretty cluttered with tools, hoses, tables, and lastly the project itself. Is it a safe area for you and the people who might help you to work in? Tools lying around as trip hazards? Fall over something because you couldn’t see it? Walking on chips or building materials such as plywood or sheet metal? Is the area wet and slick? Suspend a wing from the ceiling and it falls on you later or is so low you hit your head on it? Bleeding from the head is never something that many of us like to contemplate, but it happens. Is the air fresh enough or is all you smell is the acetone rags from the day before? Are you making things twice because you can’t see what you are working on from poor lighting? Is the drive to emergent care really long because you rotated alone that really cool rotisserie that takes two people to do and now need a doctor for your back? Further, Is it really cold inside your shop space? Not only is it not a good idea to work with cold hands or tools, but as the temperature inside your shop space gets colder it will affect the materials you are working on as well. Fasteners become less forgiving and break easier, torque values change, and driven rivets not only don’t drive and shape right, but in some cases will not be as tight as desired when holding materials together. Pull rivets rely on the tensile elasticity of the center rod to break at the proper pull thus setting the tension of the rivet to the sheet and a brittle center stem will simply break and many times not IN the rivet hole but OUTSIDE the hole leaving a sharp stem sticking up a 1/16 above the rivet face that will cut you. All of these factors can and will contribute to your safety and are directly proportional to the quality of the work that you produce as a dirty, unsafe shop with shoddy processes by definition, makes poor quality parts and assemblies. You may not have a big shop with a lot of cool tools in it, but with a little forethought you can have the nicest small shop that makes the nicest parts that anyone has ever seen. You get the picture.
The old saying about “measure twice, cut once” is so true. Another saying is that “stupid should hurt”, but it’s like saying you deserve what happens to you, which is not ever the case. The folks who have airframes of the highest quality who win awards also have the highest thresholds for safety for themselves and the folks who assist them as scars, chemical burns, or muscle tears are not part of the building process. Doing your work safely should be important to you, but few of us ever think about it or have been sat down by a veteran builder and have been talked to about what is the safest way to do something. After some time to think about it, you will find that most of the time the safer way is also the best way to do something. Take the time when you are assessing your new airplane project and plan each of the processes that you will do for not just about what you need to do and how to do it, but also about the safest way to do them and soon you will be sitting in your partially built project making airplane noises and having the time of your life.