Plaques

Bronze vs aluminum vs etched plaques: cost and durability compared

John HarrisonUpdated October 2026

Cast bronze is the heaviest, most expensive and, by every vendor’s account, the most durable choice for an outdoor plaque. Cast aluminum looks similar at a distance, costs less and weighs much less. Etched or engraved sheet metal is flat, thin and cheapest to ship. For a wall-mounted National Register plaque, the material decision is mostly a trade of budget against weight.

All prices and specifications below are as of October 2026, taken from the vendor pages listed in the sources. Vendors change prices without notice, and most publish ranges rather than fixed figures. This site has no affiliate or commercial relationship with any maker; see the plaque vendor comparison for a side-by-side of six companies.

The three types in one table

Cast bronze

Alloy and build. Gemini casts bronze in alloy NAVY-G-88-8-04 and says its alloys are lead- and mercury-free. The American Planning Association specifies Copper Development Association alloy C9220 for its plaques (88% copper, 6% tin, 4% zinc, 2% lead). Thickness scales with area: Gemini uses 5/16 inch up to 323 square inches, 1/2 inch to 575, 3/4 inch to 1,295, 1 inch to 3,599, and 1 1/2 inch beyond that.

Durability. The APA page states that cast bronze is the most durable metal for use outdoors; Masterwork Plaques says bronze can “last for decades” and holds up well in water as long as it does not pool on the surface. Gemini recommends a clear coat on all sides in harsh environments and supplies a harsh-environment clear coat at no charge on request. One exclusion worth knowing: Gemini’s warranty does not cover plaques installed in or on the ground, or mounted flat and parallel to it.

Weight. This is the figure owners most often need and vendors least often publish. The one concrete number we found is the APA’s: an 18 x 18 inch cast bronze plaque weighs 30 pounds. Treat a bronze plaque of a square foot or more as a two-person lift and a job for proper anchors; see mounting a plaque on historic fabric.

Price. Franklin Bronze Plaques publishes a full standard-size sheet, effective October 1, 2025. Selected rectangular sizes:

Extra letters are $0.53 each and extra lines $16. Franklin’s pricing page adds that images, portraits and non-standard mounting hardware cost more, and gives a sizing rule: count characters and spaces, divide by four, and you have an estimate of the square inches needed. Healy Plaques lists standard National Register plaques at $247 to $1,140 and custom ones at $247 to $1,620, cast in solid bronze or solid aluminum, with a lifetime guarantee. Impact Signs’ cast bronze starts at $218, with add-ons such as a logo (+$95), etched photo (+$550) or bas relief (+$2,100). The APA, whose plaques are made by Franklin, quotes $657 for an additional copy of its 18 x 18 inch design, excluding shipping and post.

Cast aluminum

Alloy and build. Gemini casts aluminum in alloy 365 to the same thickness schedule as bronze, and offers a larger maximum (60 x 96 inches against 36 x 96 for bronze), which reflects the lighter metal. Impact Signs quotes the same 1/4 to 1 inch standard thickness for both metals.

Appearance. Aluminum does not take a true polish in Gemini’s range: a “buffed” face is offered instead, and the “flash bronze” coating that makes aluminum look like bronze is rated for interior use only. Outdoors, a cast aluminum plaque is usually finished with a painted or oxidized background and brushed raised letters under a clear coat; Impact lists brushed satin or polished, plus oxidized tints and patinas, all sealed with clear polyurethane.

Durability. Both Impact and Gemini sell cast aluminum for exterior use. No vendor page reviewed for this guide claims aluminum outlasts bronze, and the APA chose bronze for durability. The sensible reading is that both metals are adequate for a sheltered wall; bronze has the longer track record where weather, salt or abuse are concerns.

Weight and price. Vendors describe aluminum only as “lightweight”; none publishes a weight. On price, Impact’s starting figure is $159 for aluminum against $218 for bronze. Healy uses the same price ranges for both metals, so the saving there depends on the quote. For a small house plaque the difference may be tens of dollars; for a large institutional plaque it can be much more.

Etched and engraved metal

Build. Gemini’s etched plaques come in stainless steel (alloy C304), bronze (C22000) and brass (C46400), in 1/16, 1/8 and 1/4 inch sheet, from 2 x 2 up to 36 x 72 inches. Lettering is etched into the surface and left raised or recessed; recessed text can be paint-filled. Masterwork describes the same process, chemically etching a sheet of metal, and shows polished stainless examples.

Where it fits. Etched plaques suit interior dedications, long texts and photographs (Gemini limits halftone photos to 24 x 24 inches). Outdoors they work, but Gemini restricts double-face tape mounting to interiors and requires 1/4 inch thickness for stake or post mounts. A thin etched plate is also the easiest type to mount reversibly with small screws.

Price. Neither Gemini nor Masterwork publishes etched plaque prices; both quote per job. None of the vendor pages reviewed for this guide gives an etched plaque price, so we cannot give one.

Lead times

Gemini’s lead-time page, dated October 28, 2026, gives 14 business days from order for cast plaques and 11 for etched plaques shipped in the US, plus 2 to 3 days for a quote. Impact Signs says most cast plaques take 4 to 5 weeks after proof approval and payment, with 3 to 6 business days for proofs and 3 to 5 for ground shipping. Franklin and Healy do not state lead times on the pages we read.

Maintenance

• Bronze. Montana’s SHPO guide recommends carnauba wax twice a year, and a slightly abrasive cleaner only if the surface dulls, followed by waxing. Masterwork advises a microfiber cloth first, then water and mild soap, and warns: do not use commercial solvents or household cleaners. An oxidized or patina background will continue to change tone outdoors; Masterwork notes that low-traffic bronze darkens slightly over time.
• Aluminum. The same gentle cleaning applies. The clear coat is what protects a painted background, so avoid abrasives.
• Etched. Wipe clean; paint-filled lettering can be refilled when it fades.

Choosing

For a listed house, a cast bronze or cast aluminum plaque of 8 x 6 to 12 x 8 inches covers the standard wording (see National Register plaques for what that is). Choose bronze if the wall is masonry that can take anchors in its mortar joints and the budget allows; choose aluminum if the plaque will hang on wood siding, a porch post or a sign post, where weight matters more than metal prestige. Whatever you buy, write the exact listing name from the property page into the proof; the address lookup finds it. Examples of listed properties whose plaques are seen by thousands of visitors a year include Monticello, Faneuil Hall and the Alamo.

General information, not legal or tax advice. Researched from the sources above and drafted with AI assistance; published under the editor's name, corrections welcome. See the editorial policy.