Cross-section of All-Clad bonded metal layers showing cladding construction

The Science of Bonding

Cladding Technology
& Heritage

How one metallurgist's breakthrough in bonded metals became the foundation of the world's most respected cookware brand.

The Founder

The John Ulam Story

In 1971, metallurgist John Ulam founded All-Clad Metalcrafters in Canonsburg, Pennsylvania with a single goal: figure out how to bond metals that don't naturally want to stay together. Stainless steel is ideal for cooking surfaces — food-safe, non-reactive, durable — but it is a poor heat conductor. Aluminum conducts heat beautifully but is soft and reacts with acidic foods. Copper is the best conductor of all, but impossibly expensive to use alone.

Ulam's breakthrough was a bonding process that permanently fused these materials together under extreme heat and pressure, layer by layer, so that each metal contributes its best property while its weaknesses are neutralized by its neighbors. He accumulated over 75 patents in metallurgy — many of them still active — and the core technology behind every All-Clad pan sold today traces directly back to his original process.

75+ Patents

Ulam's intellectual property portfolio covered not just the bonding process itself, but the specific alloy ratios, rolling pressures, and annealing temperatures required to create a stable, permanent bond between dissimilar metals.

The Core Difference

Cladding vs. Disc Bottoms

Most cookware brands attach a thick aluminum or copper disc to the base of a plain stainless steel shell. Heat enters through the disc, spreads across the bottom, then hits the stainless steel walls — which conduct poorly — and stops. The result: hot center, cool edges.

Disc Bottom Pan

Heat conducts only through the base disc. Sidewalls stay single-ply stainless — a poor conductor. Edges run cooler than the center.

All-Clad Bonded

Every bonded layer runs the full height of the sidewall. Heat distributes identically from base to rim — no hot spots, no cool edges.

All-Clad's bonded construction extends every layer — stainless, aluminum (or copper), stainless — continuously from the base, up the full height of the sidewalls. Heat travels through the conductive core and distributes evenly across the entire cooking surface, including the sides. This is why food cooks at the rim of an All-Clad pan the same as it does in the center.

Material Quality

18/10 Stainless Steel

All-Clad uses 18/10 stainless steel for all interior cooking surfaces. The numbers refer to the alloy composition: 18% chromium and 10% nickel. Chromium forms a passive oxide layer on the surface that makes the steel corrosion-resistant and prevents it from reacting with food. Nickel adds hardness, polish, and further chemical stability.

Critically, 18/10 stainless is completely non-reactive with acidic ingredients. Tomatoes, citrus, wine, vinegar — none of them will leach metallic flavors into your food or corrode the surface over time. This is why it is the material of choice for professional kitchen equipment globally.

18% ChromiumCorrosion resistance and the passive protective oxide layer

10% NickelHardness, mirror-quality polish, and long-term durability

Non-ReactiveSafe with acids — tomato, wine, citrus — no metallic taste

Food SafeNo PFOA, no coatings, no treatments — pure metal throughout

American Made

Canonsburg, Pennsylvania

Every bonded All-Clad collection — D3, D5, and Copper Core — is manufactured by hand at the original factory in Canonsburg, Pennsylvania, the same building where John Ulam first perfected the bonding process in 1971. American-sourced stainless steel and aluminum coils are roll-bonded together on-site, then cut, stamped, and formed into individual pan shapes.

Each pan passes through dozens of handcrafting steps — including hand-polishing the interior cooking surface and individually attaching the handle with stainless rivets. The result is batch-to-batch consistency that mass production overseas cannot replicate. When you buy a D3 skillet today, it is built to the same specification as one sold in 1985.

Note

All-Clad's nonstick (HA1) and some accessories are manufactured in China. Only the bonded stainless steel collections — D3, D5, Copper Core — carry the "Made in USA" designation.

Signature Detail

The "Star" Handle

All-Clad's patented handle has a concave, channel-shaped profile that looks like a shallow star in cross-section. This geometry serves two distinct engineering purposes. First, the air gap created by the concave shape insulates the handle from the heat rising off the pan body — keeping it cool on the stovetop without a silicone sleeve or separate grip material.

Second, the channel locks naturally into the palm of your hand when gripping, preventing the pan from rotating during a one-handed toss or pour. In a professional kitchen where a cook might flip a sauté pan hundreds of times during a service, this seemingly small detail prevents fatigue and reduces the chance of spills. The handle is riveted — not welded or screwed — to the pan body with three stainless steel rivets, making it structurally permanent.

Stays Cool — Concave channel creates an air gap that insulates the handle from stovetop heat.

Anti-Rotation Grip — Channel profile locks into the palm, preventing the pan from twisting during a pour.

Riveted Permanently — Three stainless rivets — not screws or welds — attach the handle for the lifetime of the pan.

See It in Action

Fifty years of engineering. One pan.

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