Why Coat Bronze

The use of wax to coat bronze sculpture has a long tradition.

Archaeological evidence of the 'hot-wax' technique for creating bronze jewelry dates back as far as the first evidence of bronze itself - around 3500 BC. So I imagine that it wasn't too long before someone noticed how nice a bronze statue or pendant looks when polished with wax, and how it protects against fingerprints and weather.

This is my theory, but regardless of how it started, the use of wax to coat metal sculpture, particularly bronze, started long ago and is still going strong today.

The Trouble With Wax

I've used wax myself on sculptures. But recent research definitively shows that new products are better. After using a particular polymer known as Everbrite, I'm totally convinced that polymers are better in so many ways. I chose Everbrite because it has a track record of over 30 years - the longer something's been used successfully, the more I trust it.

The Advantage of Polymer

First, let's talk about application. Polymers are much easier to apply. Simply paint it on. Anyone can do it. Whereas wax has to be applied hot requiring an experienced conservator. Additionally, before applying wax, the old has to be removed and the surface cleaned. With Everbrite, yes, any wax, grease, and dirt needs to be removed, but if you're re-coating over a polymer, no removal is necessary.

Sure, a polymer coating needs to be cleaned, but that's a much easier process of wiping with water and cloth. Furthermore, when you apply a polymer over a polymer it 'self-anneals', meaning, it bonds to the old coat automatically. Huge plus over wax! By the way, unlike most paints, polymers also 'self-level', meaning that they do not streak when applied at the right temperature.

Now let's look at another benefit of polymer, protection. Only in the last couple of decades have we developed the technology to determine just how ineffective wax is. Research conclusively shows that even the best quality wax doesn't last as long as we thought and polymers last much longer.

How long wax lasts on a sculpture is purely a guess. Some conservators claim up to two years. Others say three months. The truth is, no one really knows. For outdoor sculpture, it all depends on the weather. It's so variable that wax on one side of a sculpture may weather more than the other side. To know just how long wax lasts, you need to test the particular sculpture which is a time-consuming and expensive process. I'm shaking my head, because why even do this when we know that polymer lasts longer, up to ten years!

And it's removable with solvent. Polymer coatings will darken verdigris, and one of my client's did not like this, so I easily removed the polymer coating with xylene.

Everbrite also provides UV and anti-oxidant protection, and does not yellow. Frankly, I think it's simply nonsense to ever use wax again on outdoor sculpture.

Assessing Different Acrylic Polymers

I rely on the US Park Service and the Getty Conservation Institute for the latest research on best products and practices. Unfortunately they have not yet studied any acrylic polymers other than Incralac which they found superior to wax.

Acrylic polymers were first developed in the 60's. Incralac was the first and still widely used today. Improved acrylic coatings followed with Permalac and Everbrite about 30 years ago.

Incralac and Permalac both last outdoors 3-5 years. Incralac is known to peel so it must be removed before re-coating. Everbrite lasts 5-10 years and along with Permalac does not need to be removed to re-coat.

All provide UV protection, self-anneal, and self-level.

Everbrite provides any gradation of satin or matte finish desired at no extra charge. Permalac now comes in a satin finish but no gradations are yet available. Incralac is coated in wax to achieve a satin or matte finish.

Four coats of Permalac are required for outdoor sculpture. Everbrite just 2. So for cost, protection, and ease of application I prefer Everbrite.

The Downside

One criticism of polymer is that it's too shiny or just doesn't produce the same look as wax. This was true for early versions, but not any more. Manufacturers now mix any shade of satin or mat finish desired. In fact, the sculpture presented here is an example of just such a test of many different shades before the artist and I found the perfect match. The Everbrite company mixes any shade requested at no extra charge.

Final Thoughts

One drawback is that any polymer is solvent-based so it's flammable, and can irritate skin, eyes, and lungs. Thus, gloves, respirator, and eye protection must be used. Certain plastic containers and brush bristles will melt on contact with solvents, so I use metal containers and natural-hair brushes, available and inexpensive at any hardware store.

The final comparison is expense. When you think about all the issues mentioned above, polymer is hands-down less expensive than wax.