We are frequently hired to provide specifications and control samples for custom finishes on large projects with diverse suppliers. For example we provided specifications and control samples for over 30 different gilded finishes for Barneys New York in Manhattan. These control samples and specifications were sent to over 10 different cabinet makers and fixture manufacturers to work by. This ensured uniformity in the final results.

We have been retained to consult on several gilded state capitol domes and provide recommendations regarding repair and re-gilding of the domes, both interior and exterior.

Since every job is different with varying substrates and environmental conditions, we tailor specifications for each project. The following article illustrates this point.

In early 1921, the original West Virginia State Capitol building caught fire and burned to the ground. Later that year the legislature commissioned Cass Gilbert to build an entire new capitol building. For the next decade, work proceeded apace and in 1931 the building was completed. Rising to a height of over 300 feet, the rotunda is capped by an elaborate lead coated copper dome patterned after the one atop the church at Les Invalides in Paris. The finishing touch was a layer of 23 Karat Gold Leaf applied to the surface of the 29,000 square foot dome. The effect was magnificent. But within 6 years the gilding had deteriorated to the point of being almost non-existent. Over the years subsequent attempts to paint the surface were futile.

In 1967 the Armenian Orthodox Church built a new cathedral in New York City. At over 150 feet in height, St. Vartan's Cathedral is crowned by a lead coated copper roof that was at the time gilded with over 3,000 square feet of 23 Karat Gold Leaf. Within 3 years the gold was gone. According to contemporary accounts, the flakes would fall to the plaza and blow down 2nd Avenue, gone with the wind.

In 1929 the Baltimore Trust Company opened their new headquarters at 10 Light St. in Baltimore, MD. The Aztec Revival structure was topped with an elaborate mansard roof rising 100 feet above the 34th floor of the building. Baltimore's tallest structure had a massive copper shingled roof framed by a lead coated copper crown and pilasters all gilded with 23 Karat Gold Leaf. 65 years later when restoration work on the roof began, the original gilding was found to be well adhered, and in surprisingly good condition!

From the two former examples, it would appear lead coated copper is not a suitable surface on which to apply gold leaf. If that's true, why did the gilding atop 10 Light St. survive for over 60 years? Why does one gilded copper dome in lower Manhattan start to fail within 6 months and 30 blocks away another gilded copper dome survives for over 25 years? The answer is almost always preparation. Whether it's gold leaf or house paint, if the surface is not properly prepared, it will fail prematurely.

Whereas a painted surface will usually deteriorate within ten years of exposure to the elements, a gilded surface is expected to last upwards of 25 years. The primers and paints used under the gold leaf are mostly conventional. Why do these paints survive for so long under the gold leaf? The main reason is the thin layer of gold protects the size (adhesive) and underlying paints and primers from ultraviolet radiation. At the same time, the different layers of paints and primers work together as a system, properly adhered to each other and the substrate. The result is a stable coating that is both attractive and long lasting.

Exterior applications of gold leaf have a lustre and enduring beauty that is unrivaled by paints or other coatings. The use of gilding as exterior embellishment goes back for centuries. Properly installed an exterior gilded surface should retain its original beauty for 25 to 30 years. Improperly installed, it will disappear in a fraction of that time. There are no more demanding conditions than a surface that regularly reaches a temperature of over 150 degrees in the daytime and cycles to 50 degrees at night, for months on end. In the winter months it is then subjected to low temperatures of well below freezing with the expansion and contraction inherent to large metal surfaces subjected to such extremes of heat and cold. At the same time the surface is being subjected to constant bombardment by Ultraviolet radiation, acid rain, wind, ice, sulfide and other noxious gases, not to mention the occasional lightning strike.

With all these forces to contend with, there is no room for mistakes. From preparation through installation, every step is critical. If a gilding project is to achieve its maximum life expectancy, there are several important factors that must come into play.

1. Preparation. It cannot be emphasized enough, the surface needs to be properly prepared. In most cases the gilder encounters a surface that needs to be stripped of any previous coatings.

The stripping can be done by either chemical or physical (waterblasting or glass peaning) methods. When using either of .these techniques, the substrate and its characteristics need to be considered. Chemical stripping may be more appropriate than power washing, especially if older primers containing lead or other heavy metals are present. When chemically stripping these, abatement procedures need to be followed. Care should be taken in the choosing the type of stripper, certain caustic chemicals can do more harm than good to the surface and surrounding areas and are often hazardous to the user.

Once the stripping is completed, the surface needs to be thoroughly cleaned of any residue and stabilized if necessary. Glass peaning or waterblasting is especially useful when removing microscopic oxidation prior to application of the primer. After this step, the surface should be ready to be coated with the appropriate primer.

2. Primers. Certain primers work on some surfaces better than others and serve several functions. This is a very critical step and needs to be researched carefully. The proper primer will protect the metal or wood surface from oxidation and rot. It will also help level the surface and seal it so subsequent coatings will not be absorbed into the surface.

Most industrial primer coats are gray, black or brick red. Usually an additional coating is added between the primer and the size as a "backing color" for the gold leaf. While many picture frames and other interior elements are backed with a red color, over which the gold is rubbed back to show the under color, a yellow is used outdoors. The yellow enhances the solid appearance of the gilded surface and allows the gold to age and wear gracefully after 25 or 30 years.

3. Adhesive size. Avoid using quick size on the exterior as it becomes too brittle with age. Use only a slow drying size. Slow sizes have an open working time of 8 to 12 hours after coming to tack (generally overnite) thus allowing the gilder a considerable window to complete a designated area. The open time of the size depends upon temperature and ambient humidity and needs to be tested on- site to determine the proper interval between application of the size and installation of the gold leaf. Once the surface is gilded, it needs to be safeguarded against physical contact as it will scratch and smudge very easily.

4. The Gold Leaf . Use an alloy and weight of gold leaf appropriate for the exterior. Normally the leaf should be extra heavy weight with no less than 18 grams of gold per 1,000 sheets. The alloy should be 23 to 23 1/2 Karat gold, essentially 96 to 98% pure gold with traces of silver and copper added.

5. Timing. There are several areas where time is critical, the drying time between coats of primer and the drying period for the size. Depending on local temperature and humidity conditions, these intervals can vary greatly.

6. Ambient conditions. The work should only take place under the best possible weather conditions. The ambient temperature should always be above freezing (even at night) and it's best to work during normally dry times of year. This is a best case scenario. Let it suffice to say that gilding shouldn't take place in the late fall or during the cold winter months.

Of all the steps mentioned above, the most critical is preparation. By far this most important part of the gilding process is also the most ambiguous. There are no standard specifications for gilding. Any specifications to be had are frequently confusing.

This past summer a gilded bronze statue in a national park in Washington, DC was cleaned and restored . The specifications .originally provided were actually appropriate for cast iron and indicated materials to be used that had not been manufactured for over 20 years! If the processes outlined in the specification were used on bronze, the gilding would have failed prematurely. As it was, the gilder had the requisite experience and knowledge to recognize the problem. After consultation with the architect the specifications were changed indicating the proper procedures and materials. The project was completed with excellent results. A less experienced gilder may have attempted to follow the original specifications with disastrous consequences.

In 1983 the two copper domes on top of the Dubuque County Courthouse were gilded with 23 Karat Gold Leaf. Within 5 years the gold and primers began to flake off. The specifications for the work proved to be ambiguous and left out some critical steps. The domes were subsequently stripped and re-gilded.

Every different surface requires distinct treatments to ensure proper adhesion between the layers. What works on bronze will not work on lead coated copper or cast iron. What works on lead will not be appropriate for steel or copper. The correct system for use on fiberglass will fail on most other substrates. And there are no standard guidelines to follow.

Specifications that are available are inaccurate, outdated and misleading. Add to that the ever changing environmental and VOC requirements that vary from region to region and we end up with a recipe for failure. Materials that were successful in 1990, won't work now because the formulas have been changed! Other materials are simply unavailable.

Clearly there needs to be standardization and updating of specifications for gilding. But that will take time and effort and under whose auspices is this to be done? In the mean time, what is the solution to this problem? How do we make sure a gilding project on the exterior is going to last?

The only answer that makes sense at this time is to engage a professional gilder with a verifiable record of exterior gilding projects, someone with extensive experience gilding a variety of different surfaces. See what type of specifications and procedures are outlined in the proposal. Make certain when choosing a gilder you are comparing apples to apples. Don't necessarily make price the main determining factor. It doesn't make sense to save 10 or 15% and have the project fail in less than 5 years.

The extra time and money spent on careful research, proper preparation and the wise choice of materials are necessary investments to insure a successful gilding project. Combine these with qualified gilders to perform the work and the gold will glisten in the sunlight for decades to come.

The Gilders' Studio, Inc. - P.O. Box 631 - Olney, Maryland 20830 - Ph. (301) 929 9450 / Fax (301) 774 5037 / E-mail: inquiries@gilders.com