Water May Collect Inside Sculptures Outdoors
Water inside metal sculptures outdoors – who would have thought that would happen? I shipped a metal sculpture to Escondido, CA earlier this year. When I picked it up from our Sculpture Garden, I was surprised to find there was water inside the metal sculpture. How did that happen?
How it Happens – Water In Sculptures
With a little pondering, it was easy to understand why one would find water inside metal sculptures outdoors. I make hollow contemporary sculptures – 4 sides welded together with a volume of air inside. It is difficult to weld this 1/8″ thick metal air-tight. Even a tiny micron-sized hole will allow warm humid air to enter. When the outdoor metal sculpture is heated by the sun it expands, drawing in air through the tiny hole. This warmer air naturally holds more moisture. When the sun sets, the metal sculpture cools, the moisture precipitates from the air while the drier cooler air is expelled. Thus, water begins to collect inside the metal landscape sculpture.
Water inside contemporary landscape sculptures isn’t a problem in the summer, as long as the metal isn’t steel (then it rusts). But in the winter, trapped water will become ice and destroy metal sculptures outdoors from the inside. It make take 10 years to collect enough water to generate enough ice, but the goal is to have these contemporary landscape sculptures last for hundreds of years, not just decades.
It is interesting to think of an outdoor metal sculpture as a breathing machine. It expands, drawing in air. Then it contracts, exhaling the air. This would make a good machine for generating moisture from the air in the desert. If it was large enough it could be quite effective. If it was windy, it could be a large windmill as well, generating both electricity and water.
Solutions for Water In Outdoors Sculptures
So what is the solution? Don’t make your contemporary sculptures out of steel – they will rust from the inside, even if they are well sealed on the outside.
Alternately, coat the inside of your steel sculptures with liquid tar – like undercoating a car. I use bronze, copper, aluminum or stainless steel for landscape sculptures outdoors, even when they will end up painted.
Drill small (1/8″) holes on the bottoms of the lowest points of the outdoor metal sculptures to allow the water to drain. This is especially important for where the metal sculpture joins the base. Notice where the water drains – you probably don’t want it dripping on the base.
Don’t use dis-similar metals with your metal landscape sculptures. The moisture will cause a galvanic reaction and the lower molecular weight metal will be sacrificed for the higher. For example, don’t use aluminum combined with stainless steel – aluminum will be sacrificed by giving up electrons to the stainless steel.
Another reason to not used mixed metals for metal sculptures outdoors – they will have different coefficients of expansion. One metal will expand more than the other, which an will create an ultimately destructive high-force stress. Rubber gaskets can help avoid that problem when fabricating your contemporary sculptures.
I hope this article will help you avoid getting water inside your metal sculptures outdoors.
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