Casting Shop Safety
Casting Shop Safety
The shop is divided into halves. The front half with the workbench is used for lecturing and wax-working, and the rear half is used for everything else. Common sense dictates that minimal safety precautions are needed while work is confined to the front. All that follows pertains to the back half of the casting shop.
Safety protocols in the shop are very similar to those for the Metals Shop. Wear eye protection, natural fibers, and closed-toe shoes. Leather work-boots are preferred. Besides these, it is necessary to wear a dust mask when working with materials in the back.
Most of the tools in this shop require the user to be tool-tested before they are permitted to use them. To arrange a tool-test please refer to the Artisans Asylum web page menu item under “Learn.” Shop classes frequently include tool-testing as part of the curriculum. Tool-testing is mostly focused on safety rather than proficiency.
WORK WITH A BUDDY!
Two people are required for melting and casting metal in the shop. One tends the metal while the other manipulates the molds and operates the vacuum caster. All other shop operations can be performed solo. Handling molten metal poses a risk of very serious injury, and a buddy may be needed to call 9-1-1 if necessary.
Report Safety Concerns
The casting shop is engaged in a perpetual effort to improve safety, while allowing the greatest utility to the shop user. If you feel unsafe, please report your concerns to the shop lead. Please report any breakages and excessive wear. We will thank you for it. It takes work to make the shop run as smoothly as possible, and that work can’t be directed without information from shop users.
Handling Hot Things
Things in the shop can give you severe burns without being visibly red-hot. Always assume something on one of the hot-benches is dangerous, unless you are the first to arrive in the morning. Wear gloves and pick things up with tongs. Check the temperature by holding the back of your hand over a suspicious article.
If there is a large molten metal spill in the shop, the concrete in the floor may be damaged. Sometimes it can go off with a “pop.” This is only a serious hazard in a foundry with a much larger melting capacity, but it should be noted in case someone gets ambitious in the future.
Emergency Shower and Eyewash
99.99% of the time these are obstacles in the shop, but you will be really happy they are there in the exceedingly unlikely event that you need them. If you are on fire or have given yourself a serious burn or if you have gotten something in your eye (in spite of all the precautions listed below) do not hesitate to use them.
DO NOT pull the chain on the safety shower if you don’t have an urgent need to do so. You will be shocked at how fast the water comes out, and it will immediately flood the building since there is no drain for the water.
Ventilation
Run the ventilators any time dusty or hot activities are performed. This includes mixing of investment, firing of lost-wax molds, ANY furnace or torch activity, melting metal, running the vacuum caster, demolding sand castings.
The power switches for the two rooftop ventilation fans are located on the back wall of the shop. The fans don’t come on immediately when you flip the switch, wait a few seconds. The ventilation in the casting shop may be the best in the AA complex, but that isn’t saying an awful lot. The fans are simple toggle switches with no timers. You need to turn the fans off manually if they have run an hour or more after finishing work.
In addition to the rooftop fans, there is a benchtop dust hood for weighing and mixing investment. This product poses a separate hazard from crystalline silica. Place the scale for weighing powder in the hood, and mix the investment with water under this hood.
The two rooftop ventilators in the shop working together replace the air in the room in about 30 minutes, assuming the air is well mixed. Sweeping the shop floor can raise some crystalline silica dust that will hang in the air for roughly this amount of time.
Eye Protection
By far this is the most important personal safety measure. Here is a partial list of the hazards:
Molten Metal: Castings made in the shop are under 200 grams, but ANY quantity of molten metal poses a severe hazard for the eyes.
Steam Explosions: Hot lost-wax molds are routinely quenched in cold water. If this is done improperly, hot water can shoot out of the bucket.
Torch: The oxy-propane torch is used for melting metals in ceramic ladles. Wear shaded goggles for this to protect from metal splashes and bright light.
Furnaces: The normal firing temperature for a lost-wax mold is 1350 F. Goggles will protect your eyes from infrared radiation as well as chips of material that may flake off the molds.
Dust: The powdered materials used to make the lost-wax and sand molds can acutely irritate the eyes.
Dust Masks
Wear an N-95 mask at a minimum. Better is a P-100 dust mask. Chemical respirators are not necessary in this shop. Here are some of the hazards you must protect yourself from:
Crystalline silica: The investment used in the lost-wax process contains a large fraction of flint powder. It should be handled under the benchtop dust hood, but additionally dust masks are required when handling powder from the supply drum. All investment should end its use life in the quench bucket as a saturated sludge in the bottom of the bucket.
Metal fumes: This is most pronounced with melting brass, which creates a fume of very fine zinc oxide. It poses a hazard of heavy-metal poisoning if it escapes the draft from the ventilation. As with the dust hazard, a dust mask provides an important second layer of protection.
Vacuum pump smog: The pump in the vacuum caster presently has no oil filter on its exhaust. It comes out of the back of the machine and largely gets pulled away by the ventilators, but you should always protect yourself from this chemical hazard.
Hot Gloves and Aprons
There are two styles of hot gloves in the shop. For most purposes, the reddish leather welding gloves are sufficient for hot work. These protect the hands from heat radiation and deflect sparks and splashes of molten metal. They DO NOT insulate the hands from heat, so they can’t be used to hold hot things.
Always wear a leather apron when handling molten metal. This protects from metal splashes and material ejected in a steam explosion. Wear the long leather gauntlets if you have a short-sleeved shirt. Avoid exposed skin. Wear a face shield too if you want extra protection, but metal rarely splashes upwards.
The yellow Kevlar insulated foundry gloves protect the hands well enough to grab hot things. You lose a lot of dexterity in these, so it is always better to manipulate hot things with tongs wearing the leather welding gloves.
Closed-Toe Shoes
Molten metal can land on your feet. Duh. In sandals you are literally asking for a crippling injury. Closed-toe shoes made from synthetic materials will be ruined by splashes of molten metal but they provide a modicum of protection. It is always best to wear leather work-boots.
Natural Fiber Clothing
As with the shoes, you need to protect your body from metal splashes. Natural fiber clothing resists splashes from molten metal 100 times better than synthetic fibers. No shorts. If you wear a T-shirt, be sure to don the long leather gauntlets to protect the arms.
Food in the Shop
No food.
Wax Injector, Vulcanizer, and Soldering Pencils
These tools have hot surfaces that can give you 1st- or 2nd-degree burns if you aren’t careful. The wax injector is frequently left on, so it may be hot when you don’t expect. The soldering pencils are used for wax-working.
Sharps
The process for making vulcanized rubber molds involves the use of very sharp surgical blades. To safely dispose of used blades, wrap them in masking tape before putting them in the trash.
Solidified metal after pouring can have sharp projections. Watch out for these in scrap metal and metal splashes.
Flammable Solvents
There is very little use for solvents in this shop. There exist a few wax-working lamps that burn denatured alcohol. Handle these carefully.
Electrical Hazards
We have a few pretty big cables on the floor to power the electric furnaces. They are shielded from direct splashes of molten metal. Nevertheless, if you have a large metal spill please check in the vicinity that the wires are okay.
