Metal Working
ID | Metal-working Tech | Ingestion Haz | Inhalation Hazard |
Skin Contact Hazard | Other Hazards |
Precautions |
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1 |
WELDING, BRAZING, & SOLDERING |
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2 |
Oxyacetylene Welding Fire Hazards |
Fire and explosion hazards |
Welding surface should be fireproof, made of steel or firebrick; don't use asbestos sheeting; wooden floors & walls should be covered with fireproof materials; remove combustibles/ flammables; don't weld on containers that have held combustibles/ flammables | |||
3 |
Oxyacetylene Welding Cylinder Precautions |
Don't move cylinders w/out valve protection cap;make sure hoses can't be tripped over/don't contact grease;make sure connections are gas tight;use proper tools to open valves away from self;purge lines to remove mixed gases;close valves before relighting | ||||
4 |
Oxyacetylene Welding Safety Hazards |
Thermal burns |
Hot metal, flying sparks, infrared radiation can cause severe thermal burns on exposed skin |
Wear leather gloves, long-sleeve 100% wool or flame-retardant cotton shirts, pants, leather apron to protect from burns; don't wear flammable clothing w/cuffs, pockets; wear hightop leather boots w/out rubber/crepe soles & do have safety toes | ||
5 |
Oxyacetylene Welding Health Hazards |
Phosgene extremely toxic; carbon dioxide, acetylene cut off oxygen to lungs; carbon monoxide & fluoride flux fumes highly toxic; metal fume fever; metal dusts irritating; metal fumes highly toxic |
UV can cause skin cancer, eye damage, sunburn; can react w/ chlorinated hydrocarbons to form phosgene |
Visible light can cause eye strain/headaches; infrared radiation can cause skin burns/ chronic eye inflammation/ heat cataracts; copper/ zinc/ iron/ nickel/ magnesium can cause metal fume fever; lead/cadmium/ manganese/ chromium/ beryllium/ nickel highly toxic |
Wear welding goggles w/shade #4-8; don't store chlorinated hydrocarbons where uv light can reach; know composition of metals/rods; use dilution ventilation of at least 2,000 cubic feet/minute/welder; use local exhaust system, NIOSH-approved respirator | |
6 |
Arc Welding Safety Hazards |
Increased risk of fire, thermal burns from sparks, heat stress; high risk of electric shock due to large electric currents used |
Wear protective clothing/leather leggings/sleeves; prevent fire; install & ground electric arc welders according to manufacturer; cables/connectors should be of proper size, regularly inspected, & properly secured; inspect electrode holders, cables | |||
7 |
Arc Welding Health Hazards |
Ozone highly toxic/causes lung irritation/congestion/ chemical pneumonia/ chronic bronchitis, can be fatal; nitrogen dioxide highly toxic/causes chemical pneumonia, emphysema; metal fumes/ manganese/ fluoride fumes highly toxic |
Eye damage from uv light |
Chromates may cause lung irritation, allergies, nasal septum ulceration, lung cancer; plasma arc welders produce much higher concentrations of ozone, nitrogen dioxide, metal fumes & produce high noise levels |
Use fireproof uv radiation screens around welding units; coat walls w/zinc oxide to reduce reflection; leave 20 inches at bottom of screen for ventilation; wear welding helmet over impact-resistant flash goggles (#10-14); use local exhaust ventilation | |
8 |
FOUNDRY |
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9 |
Mold Making |
High-silica sands, silica flour, investment plasters highly toxic (can cause silicosis); formaldehyde extremely toxic; isocyanates highly toxic; asbestos extremely toxic; ethyl silicate highly toxic |
Formaldehyde moderately toxic; hexamethylene-tetramine causes skin irritation by decomposing to formaldehyde |
Formaldehyde known carcinogen; asbestos can cause lung cancer, mesothelioma, stomach/intestinal cancer; french chalk can contain high amts.of free silica |
Use foundry sand for molds,not high-silica sands; use local exhaust ventilation when mixing silica, or use NIOSH-approved respirator; avoid formaldehyde/polyurethane resins; wear gloves, goggles; DO NOT use asbestos/silica flour/French chalk; use graphite | |
10 |
Burnout of the Pattern |
Carbon monoxide highly toxic; wax decomposition fumes highly irritating; styrene, hydrogen cyanide gases highly toxic |
Ventilate with local exhaust system (canopy hood over burnout furnace) | |||
11 |
Melting the Metal |
Carbon dioxide & carbon monoxide (highly toxic) from furnace; lead fumes from lead metal & bronze highly toxic; zinc fumes from bronze & brass moderately toxic; nickel fumes may be extremely toxic (nickel carbonyl can be in it) |
Natural gas/propane gas cause fire/explosion hazards; nickel fumes/dusts can cause lung/nasal cancer; using alloys of unknown composition can result in exposure to other toxic metals;furnace can cause heat stress; infrared radiation causes skin burns |
Gas furnaces should be connected by gas company; use alloys of known composition only; avoid nickel/lead; use local exhaust ventilation;wear infrared goggles,face shield,long-sleeve wool shirt, insulated leggings, jacket, apron, gloves | ||
12 |
Pouring the Metal |
Hazardous metal fumes released during pouring; thermal decomposition of organic materials release formaldehyde, carbon monoxide, acrolein, cancer-causing substances; polyurethane foam can release hydrogen cyanide gas (extremely toxic) |
Molten metal splashes can cause severe thermal burns |
Manual pours limited by weight of crucible & person's strength; molten metal splashes on cement result in heat vaporizing water in cement, causing it to violently break apart in steam explosion |
Make sure you can lift crucible; don't pour by yourself; use two-person shank and ring/mechanical lifting equipment; embed molds in damp sand 18 inches deep, enclosed in metal; foundry floor should have raised metal grate/covered w/sand; use canopy hood | |
13 |
Removing the Mold |
Intense temperatures convert normal quartz sand to highly haz. silica; sandblasting can cause silicosis in a few years exposure |
Abrasive blasting creates loud amounts of noise, which can cause hearing loss |
Wear NIOSH-approved toxic dust respirator;vacuum/met mop;don't use sand for abrasive blasting;use alumina/silicon carbide/walnut shells;avoid foundry slags w/arsenic;inspect blasting machine often;wear hearing protection, protective clothing,blasting hood | ||
14 |
FORGING & METAL FABRICATION |
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15 |
Cutting, Piercing, & Filing Metals |
Small metal filings can damage skin, eyes; saws, drills, metal snips can cause cuts |
Electric drills can cause electric shocks if they're not properly grounded |
Wear ANSI-approved goggles to protect eyes against flying metal pieces/filings; make sure electrical equipment properly grounded & wiring is in good condition; handle tools w/sharp edges carefully; fasten metal piece in vise; put tools away after use | ||
16 |
Forging |
Furnaces for hot forging give off large amounts of carbon monoxide and other highly toxic fumes & gases |
Careless handling of hot objects can cause thermal burns; furnaces produce infrared radiation, which is an eye & skin hazard |
Noise is a hearing hazard in both hot/cold forging; large amounts of heat from furnaces can cause heat stress |
Do forging in separate room; wear ear plugs/ear muffs; equip all furnaces w/chimneys/canopy hoods; use exhaust fan; wear protective goggles (shade # 1.7-3.0); wear long-sleeve, cotton shirt, leather gloves, safety shoes, face shield; keep room cool | |
17 |
Annealing |
Sulfuric acid/other acids & Sparex highly corrosive to skin, eyes; diluted acid less haz., but can cause burns |
Use of torches involves flammable gases, such as propane & acetylene, and oxygen/compressed air (fire & explosion hazards); furnaces can cause heat stress |
Use precautions w/gas torches, fuel-fired furnaces; wear protective goggles, gloves, apron; add acid to water; use Sparex; avoid acids; if acid splashes on skin, rinse w/water, if in eyes, rinse for 15-20 minutes; neutralize acid w/sodium bicarbonate | ||
18 |
SURFACE TREATMENT OF METALS |
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19 |
Mechanical Treatment |
Benzine (VM&P naphtha) moderately toxic |
Benzine moderately toxic; hot pitch is skin irritant & frequent, prolonged contact can cause skin cancer |
Heating pitch & use of benzine to remove pitch from the metal creates fire hazards; engraving tools can cause cuts if used improperly |
Don't smoke/have open flames; store solvents in safety cans, store rags in disposal cans & remove each day; use adequate exhaust system; use gloves when handling hot pitch or benzine; handle engraving tools carefully; cut away from yourself | |
20 |
Etching & Photoetching |
Nitrogen dioxide gas highly toxic, causing pulmonary edema, pneumonia, emphysema; methyl cellosolve acetate highly toxic; xylene highly toxic; carbon arcs give off nitrogen oxides, ozone, metal fumes (highly toxic) |
Nitric acid/other acids highly corrosive to eyes,skin; methyl cellosolve acetate highly toxic; xylene moderately toxic; hot pitch can cause burns |
Methyl cellosolve acetate can cause adverse reproductive effects, kidney damage, anemia; methyl cellosolve acetate & xylene flammable; carbon arcs emit ultraviolet radiation, which cause sunburn, eye damage; hot pitch is fire haz. |
Wear gloves, goggles, protective apron, NIOSH-approved organic vapor respirator; add acid to water; if acid splashes on skin, rinse w/water, if in eyes, rinse for 15-20 minutes; use local exhaust system; use commercial resists; don't use carbon arcs | |
21 |
Electroplating & Electroforming |
Sulfuric acid is respiratory irritant; lacquer vapors & mists highly toxic |
Risk of electrical shock; caustic soda, sulfuric acid highly corrosive; sulfuric acid skin & eye irritant; lacquer vapors moderately irritating |
Send pieces to commercial electroplater; wear rubber gloves, goggles, protective apron, NIOSH-approved respirator, rubber-soled shoes; add acid to water; if acid splashes on skin, rinse w/water, if in eyes, rinse 15-20 min.; use local exhaust system | ||
22 |
Electroplating & Electroforming (continued) |
Install ground fault circuit interrupter; install electroplating unit on wooden/nonconducting surface, not on metal; don't use metal chair; don't touch bath, wires, electrodes w/bare hands; unplug power before adjusting bath; use special rectifiers/tape | ||||
23 |
Anodizing |
Hydrofluoric acid can be fatal |
Trisodium phosphate alkaline & can cause respiratory irritation; hydrofluoric acid highly corrosive to lungs |
Trisodium phosphate alkaline & can cause skin, eye irritation; hydrofluoric acid highly corrosive |
Titanium & tantalum are combustible; their filings & dust will burn; burns can occur without pain hours after exposure to hydrofluoric acid; hydrofluoric acid can cause chemical pneumonia, chronic bone/teeth or kidney damage; risk of electrical shock |
Wear insulating rubber gloves, goggles, protective apron, face shield; AVOID hydrofluoric acid, use wet sand & emery paper; only use hydrofluoric acid in lab hood or w/acid gas respirator; if contact w/skin/eyes, flush for 15 min. & call doctor right away |
24 |
Patinas |
Patinas highly poisonous; concentrated acids highly corrosive; benzine moderately toxic |
Chlorinated solvents highly toxic; patinas highly poisonous; spray mists haz.; concentrated acids highly corrosive; potassium cyanide forms poisonous hydrogen cyanide gas; benzine moderately toxic, lacquers highly toxic |
Chlorinated solvents can be absorbed through skin; patinas corrosive; concentrated acids highly corrosive; benzine, lacquers moderately toxic |
Chlorinated solvents probable carcinogens; if heated w/torch, decompose to poisonous phosgene gas; diluted acids cause skin, eye irritation; oxidizing agents can cause fires/explosions; benzine, lacquer solutions flammable |
Use mineral spirits/detergent solutions to clean/degrease metals; don't use antimony/ arsenic/ cyanide/ mercury; wear goggles, gloves, protective apron; don't add acids to sulfides when coloring; store oxidizing agents away from solvents |
25 |
Patinas (continued) |
Use glove box, local exhaust ventilation, NIOSH-approved toxic dust respirator; don't eat, drink, smoke in studio; dip/brush patinas instead of spraying; don't have smoke/open flames in working area; dispose of waste solvents & rags daily | ||||
26 |
Niello |
Lead sulfide dust from grinding highly toxic |
Lead fumes emitted from melting of lead highly toxic; lead sulfide dust from grinding highly toxic
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Do all melting & heating in local exhaust system; wear NIOSH-approved respirator; don't eat, drink, smoke in studio; wash hands carefully after work; wet mop surfaces; heat ammonium chloride paste inside a hood | ||
27 |
Gilding |
Mercury metal poorly absorbed
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Mercury metal highly toxic
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Mercury metal highly toxic
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Acute mercury poisoning is accompanied by metallic taste, excessive salivation, swelling of gums/mouth, vomiting, bloody diarrhea, kidney failure, bronchitis, pneumonia; chronic mercury poisoning affects central nervous system |
DO NOT USE mercury amalgams; store mercury under water in closed containers; if mercury used, make amalgam on tray to contain spills; use local exhaust ventilation; clean up spills w/mercury spill kit; wash contaminated surfaces w/ferric chloride |
28 |
CLEANING, POLISHING, & FINISHING |
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29 |
Pickling |
Ammonium bifluoride highly toxic |
Nitric & sulfuric acids highly toxic; hydrofluoric acid highly corrosive; potassium dichromate highly toxic |
Nitric & sulfuric acid, ammonium bifluoride highly toxic; hydrofluoric acid highly corrosive; sodium bisulfate moderately corrosive; potassium dichromate moderately toxic |
Boiling acid solutions can be very hazardous due to danger of splashing; dichromates are probable carcinogens; hydrofluoric acid can cause lung irritation, chemical pneumonia, chronic bone/teeth/kidney damage; may be fatal |
Wear gloves, goggles, protective apron, respirator, face shield; if acid splashes on skin, rinse w/water; if in eyes, rinse for 15-20 min.; cover acid baths; use local exhaust ventilation; use bifluoride pastes; neutralize acid w/sodium bicarbonate |
30 |
Grinding, Polishing, & Other Mechanical Techniques |
Lead-containing dusts highly toxic |
Lead-containing dusts highly toxic; free silica highly toxic, causing silicosis; formaldehyde highly irritating; silica-containing abrasives may cause silicosis from chronic inhalation |
Cutting fluids may cause dermatitis |
Flying metal particles can cause eye damage; synthetic, semisynthetic, soluble cutting oils contain nitrosamines, which cause cancer in animals |
Wear goggles, face shield, respirator; grinding wheels should have eye shields; don't wear loose clothing; don't use sandstone wheels; use silicon carbide/alumina; use wet techniques; use local exhaust ventilation; use cutting oils w/out amines/nitrites |