Man’s discovery of smelting ore to separate metals led to many creative methods of shaping metals. The Industrial Revolution spawned mass-production technologies for casting, stamping, forging, raising, spinning — and other techniques that produce duplicate metal products at affordable prices — using base metal alloys and electroplated finishes.
Today’s metal serve-ware is made using most of the following production techniques. Because quality is a synthesis of raw materials and production methods, this post will help you understand how metal serve-wares are made.
More than 6,000 years ago,
early man used rocks and bones to beat metals flat.
He use the same primitive tools to cut, shape and decorate the metal.
Today’s refineries produce flat, rolled sheet stock in a range of alloys from which artisans hand cut shapes using special saws. Mass-producers cut duplicate shapes with steel dies using a mass-production technique called stamping (similar to how a cookie cutter stamps out duplicate shapes of dough).
Die-stamping (also called drawing or vaulting) metal is a complex, capital intensive method for mass-producing three-dimensional hollow shapes. A pre-cut flat shape of metal is pressed between positive and negative dies that draw or stretch the metal to assume the shape and depth of the dies.
Some metals are more brittle than others and must be annealed (heated) in order to be stamped.The heavier the metal and the thicker the gauge of the metal, the heavier and costlier are the dies and stamping equipment — but speed and perfect duplication of products amortizes this costly technology.
After early man learned to use heat to separate metal from ore,
he developed a way to cast molten metal —using molds.
Duplicating objects in molds began with Ciré Perdue (lost wax)—a technique wherein a shape created in wax is encased in clay, plaster or sand. When heat is applied, the wax melts and runs out through a hole in the plaster or clay or sand and the wax is lost.
Molten metal is poured into the shaped cavity left by the lost wax and when it solidifies and the clay, plaster or sand is removed— a perfectly cast metal reproduction of the original shape is revealed.
When I introduced ‘casting’ to my FIT students, I asked if any of them ever made creepy crawlers. Most students laughed as they remembered using this very popular ‘casting’ kit for children.
My nieces and nephews loved to ‘scare’ me with ‘creepy-crawlers’
made by pouring liquid Plastigoop into metal molds resembling bugs.
The Plastigoop was cured by heat and cooled. When the rubbery ‘creepy’ replicas were removed from the molds — the fun began!
Molds made of diverse materials are capable of producing many hundreds of duplicate products and artisans and mass-production factories have perfected many methods of casting duplicate metal shapes. Industrial methods are varied depending upon the industry but for anyone casting metal, care must be taken to avoid impurities in the metal —which cause pitting and porosity. Articulation of the design, elimination of mold markings and quality polishing are critical elements of castings.
Any solid object can be used to make a mold:
from which is made a casting.
When I designed handbags for a NYC company, I bought a horse-head bottle opener in Italy and took it to a casting artisan in NYC—who made a mold of the horse-head. Using the mold, he cast hundreds of molten metal duplicates of the horse-head, gold-plated them, and soldered them to hand-bag locks.
Our ‘horse-head’ handbag won by a nose: I still enjoy mine!
In order to raise or stretch metal into three-dimensions, early man pounded metals flat and continued beating the metal against shaped surfaces with rocks and bones.
This method is still used by metal smiths although hammers and anvils have replaced rocks and bones. Hammer marks may be retained —or smoothed with a planishing hammer.
Forging is the art of shaping metals—especially iron— by hammering.
Most of the ornate iron gates we see around the globe are hand-forged.
Sections of forged metal pieces can be joined by soldering.
Q. How does a flat-bottom metal shape become a round-bottom metal shape?
Each flat-bottom hollow shape begins as a flat round disk — cut from metal sheet stock. A single disk is placed between heavy, deep positive and negative steel dies in a large automatic press.Tremendous pressure stretches the disk into a deep, flat-bottomed, hollow shape.
A metal mandrel—made in the exact deep and rounded configuration of the finished product— is securely mounted on a lathe.
A die-stamped metal shape with a flat bottom is placed over the mandrel. A skilled operator presses a lubricated metal lever against the flat-bottom and as the lathe rapidly spins, the operator increases pressure—until the flat metal appears to ‘flow’—and the flat bottom becomes round.
Labor costs for spinning are amortized by the speed of the process.
Pat Breen: EYEWITNESS TO QUALITY
MY NEXT POST: KEYS TO SERVE-WARE QUALITY