Color-Anodized Aluminum Tumblers: The Seaplane Patent Behind the Patio Set

By Matthew Partsch - Owl and Twig Vintage - October 1, 2026

The rainbow-colored metal cups that showed up at every cookout from the Eisenhower years through the Carter years get their finish from a process a British engineer patented in 1923 to keep saltwater corrosion off seaplane engine parts, not to make drinkware pretty, and the company that put color into that process patented nothing about a tumbler at all.

A seaplane patent, not a housewares one

Every color-anodized aluminum tumbler on a thrift-store shelf owes its finish to a patent filed for an entirely different industry. G.D. Bengough and J.M. Stuart filed British Patent GB223994A, "Improved process of protecting surfaces of aluminium or aluminium alloys," on August 2, 1923; it was accepted on November 3, 1924. Their process ran aluminum as the anode in a bath of three percent chromic acid, built the voltage up to 40 volts over fifteen minutes, held it there for another thirty-five, then raised it to 50 volts for a final five, at a minimum bath temperature of 40°C. According to Wikipedia's own account of the process, it was first used on an industrial scale that same year to protect Duralumin seaplane parts from corrosion, a maritime aviation problem with nothing to do with picnics.

The patent covers protection, not appearance. The process it describes thickens the aluminum's own naturally occurring oxide layer into a harder, more corrosion-resistant skin, and the only cosmetic step it mentions is a post-treatment finish of lanoline, oil, or paint, applied for weatherproofing rather than color. Nothing in Bengough and Stuart's filing anticipates a drinking cup.

The 1927 shortcut, and the 1936 color breakthrough

Chromic acid anodizing is slow and comparatively expensive to run at scale. Four years later, C.R.R. Gower and O'Brien & Partners filed British Patent GB290901A, "An improved process for providing a resistant coating upon the surfaces of aluminium or aluminium alloys," on October 20, 1927, published May 24, 1928. Their version ran the same basic reaction in a bath of sulfuric acid instead, roughly one and a half to two pounds of acid per gallon of water, at a minimum temperature of 60°F and only 6 volts, for 25 to 70 minutes depending on the finish wanted. Sulfuric acid anodizing was cheaper to run and easier to control, and it became, and remains, the dominant commercial process.

What a sulfuric-acid bath produces is not a solid skin but a porous one, full of microscopic channels running down into the oxide layer. That porosity is what eventually made color possible. In 1936, according to a trade-publication history of anodizing on pfonline.com, Italian researcher G. Caboni worked out "electrocoloring," a technique for driving dye down into those pores before a final sealing step closes them again and locks the color in permanently. That sequence, anodize, dye, seal, is still the basic recipe behind every colored anodized aluminum object made today, tumblers included.

The three-decade gap before the patio table

Nearly thirty years separate Bengough and Stuart's 1923 patent from the tumbler's arrival on an American patio table. The Smithsonian's National Museum of American History catalogs a set of nine anodized aluminum tumblers in its own collection, dating them to the late 1950s and 1960s and describing them as "a common fixture of the 1960s backyard or patio culture established in the U.S. in the 1950s." The museum's own object record explains why anodizing mattered for this particular use: "the anodizing process increased the thickness of the oxide layer on metallic parts, making the popular serving ware unbreakable, rust-resistant, and colorful," a combination glass and enameled steel could not match at the same price point.

The Smithsonian's record adds a detail that explains how so many of these sets reached American kitchens without ever being purchased outright: "many were giveaways given along with or filled with a desirable foodstuff or awarded for coupons in grocery store giveaways." A set of anodized tumblers was, for a lot of postwar households, a premium rather than a purchase.

The timing lines up with a broader postwar story this blog has covered before. Aluminum production capacity built up for wartime aircraft manufacturing found a second life in consumer goods once the war ended, the same dynamic behind Owl and Twig's guide to the aluminum Christmas tree, which traces its own 1950s arrival to the same glut of aluminum-industry capacity looking for a new market. Anodized drinkware is a second, warm-weather branch of that same postwar aluminum story.

Who actually made these sets

A targeted search turned up no design patent and no federal trademark for an anodized aluminum drinking tumbler as such. West Bend Aluminum Co., one of the best-documented makers, did register its own mark, WEBALCO, but the federal record covers electric skillets (filed 1958) and electric coffee makers (filed 1964), not drinkware. No comparable registration for a tumbler line turned up for West Bend or any other maker. The category appears to have grown the way plenty of mid-century housewares did, through ordinary manufacturing and retail competition, with no single company controlling the design or the name.

At least eight manufacturers sold these sets, often within a few years of each other. West Bend Aluminum Co., of Wisconsin, marketed its own line under the name "Color Glo." Perma-Hue, of Edgerton, Ohio, and Regal Ware, also Wisconsin-based, were both domestic competitors. Royal Sealy made sets in Japan; Bascal and Heller both made sets in Italy, the source of many pieces that turn up in the secondary market with "Italy" stamped on the base. Norben Ware and Zephyr Ware round out the list of named makers documented by collectors. A large share of surviving sets carry no mark at all, and collector researcher Collectors Weekly points to Krome Kraft, a line made by the New York metalware firm Farber Brothers, as a likely source for some unmarked pieces, a reasonable guess rather than a confirmed attribution.

How to tell a real vintage set

Check the base first. A stamped maker's name, "Italy," "Japan," or "Made in USA" on the bottom is the single most useful identifying mark when it is present, and it is present less often than collectors would like. Genuine vintage pieces are spun or drawn from a single sheet of aluminum, and the interior bottom often shows faint concentric tooling marks left by the spinning process, a texture a machine-pressed modern piece is less likely to reproduce.

Decades of actual handling leave a specific wear pattern. The anodized color coat thins fastest at the rim, where lips and fingers made the most repeated contact, and at the base, where the tumbler sat on tables and countertops. On a piece with decades of real use behind it, those high-wear points often show the plain silver aluminum underneath, peeking through a color coat that is otherwise intact everywhere else. A uniformly saturated color with no wear anywhere at all is a point in favor of a recent piece, not an old one.

The look-alikes: new sets sold as "retro"

Modern reproductions are easy to find and, for the most part, plainly marketed as new. Trademark Innovations, a current houseware brand, sells a boxed set of six 14-ounce "Retro Aluminum Tumblers" in assorted colors, manufactured in China, explicitly described by the retailer as hand-wash-only and styled for "a summer cookout, beach party or for everyday use." Nothing about the listing claims the tumblers are vintage; the word doing the work is "retro," a style reference rather than an age claim. A new set like this tends to arrive more uniform than a genuine old one, consistent color saturation across every cup, crisp, machine-even stamping on the base if there is any mark at all, and no wear anywhere.

A second, unrelated source of confusion is modern double-wall stainless steel drinkware, also commonly sold under the word "tumbler." These share a name and a rough silhouette with the vintage aluminum pieces but nothing else, different metal, different manufacturing process, and no connection to the anodizing history this guide covers.

What vintage sets sell for now

No confirmed auction-house realized price could be found for color-anodized aluminum tumblers; the category trades almost entirely through everyday resale listings rather than formal auctions. A set of six unbranded tumblers sold on eBay for $35.00, a representative figure for a complete set in good color with no chips or heavy wear. Individual pieces and smaller lots typically ask less, and sets carrying a visible, desirable maker's mark, or a full matching set with its original cardboard sleeve or metal caddy, tend to command more than an unmarked lot of mixed pieces. Every figure here is an asking or completed-listing price from the general resale market, not a verified auction record.

Hunting a set of color-anodized tumblers, a West Bend Color Glo piece, or anything else from the postwar patio table to check against this guide?

Search anodized aluminum tumblers Search vintage aluminum cups Search West Bend aluminum

For another Field Guide built around a founding patent that has nothing to do with the product collectors actually chase, see Owl and Twig's guide to Crayola's 1891 carbon-black patent. For more on the postwar aluminum boom that put these tumblers on the table, see the guide to the aluminum Christmas tree. See more Field Guides