CAST MARBLE OUTDOOR PLACEMENT
Further to previously given information, this is a more detailed faq sheet on what can be expected when placing cast marble out of doors. What comes to play on the sculpture are the elements; rain, sun, mould, freezing, acid rain, to name a few. These forces are capable of breading down even the hardest of solid rock into soil and dust. Of course this is over a very, very long period of time.
As of August 2007, it has come to Foot's attention that there is some inconsistency in the resin that has been supplied and which is used in the cast marble process. This is of no significance on small and medium sized pieces, and for all pieces if displayed indoors. However, thermal expansion and contraction from extreme heat and cold does have an impact on the larger pieces in cast marble, at least some of them, due to the resin variable. For this reason there is a degree of gamble in placing large pieces in cast marble out of doors. They may be fine, many have been, but unfortunately it gets down to that "due to the actions of a few....", that impacts on "the many". Regrettably it is necessary to withdraw the guarantee on pieces placed out of doors. It should be noted that cold does not seem to cause cracks. Pieces have been deliberately left outside in Ohio, disappearing below the snow in winter, and have been unscathed. Hot temperatures, above 33 degrees C do cause cracks on some pieces, but only if placed in the direct sun.
Realistically, marble is one of the softer stones, and this is the reason it is a great medium for shaping into sculpture. Being not as hard as granite or basalt, we still have solid evidence that even after three thousand years, the works left by the Greeks are still in relatively good shape. They have weathered, yes, but they are still doing their job.
However this track record can be improved on. Marble can be hardened up, and this is what is done when it is saturated with resin. This also removes the porosity which contributes to itís natural breakdown, and as well the the minute cracks and flaws which enable temperature differences to split stone. The resin we use is polyester, exactly the same type of resin used in fibre glass boats, and in the poly marble sinks and tiles that are marketed today.
In short, if natural marble holds up for 3000 years, cast marble should have a lifetime of several times that; in any case relative to our life times, we donít have to worry. Personally I get a lot of satisfaction out of knowing that someone, or something, will be getting some pleasure out of these pieces a very long time from now.
However, that being said, the actual polish on the surface is another matter. This polished layer is only a fraction of a millimeter deep, and it doesnít take much to lose that glistening shine. Almost all of the classical sculptures destined for outdoors were never polished to a high gloss for this reason, they would revert to a matt finish shortly outside anyhow.
Fortunately, modern technology gives us a way of protecting that high shine, by way of weather resistant gel coats and clear laquers. All fiberglass boats, and all polymarble products are coated with a gel coat layer, either clear or pigmented. The best way to keep a perfect paint job on a vehicle is by applying a clear overcoat, the best being a two pack laquer. Essentially this acts as a second skin, or permanent wax job, to protect the underlying paint. But then this can be taken another step. What about protecting the clear coat? OK, that is where periodic wax coats come in. Something has got to wear, so the best strategy is to make it something that can easily be put back on, i.e. a coat of wax, every three to six months.
Now, what if we forget. Well, the two pack clear is pretty good on its own, and I would guess that 10 to 20 years is a reasonable estimate, with no waxing at all. If the piece is in partial shade, a lot longer. Frankly, I do not know, the manufacturers will not commit themselves to a guarantee, and I have to pass that along in mine. I know that the cast marble will hold up indefinitely, but keeping that glossy shine by using a clear overcoat, all I can say is this. My neighbour has put a Manta Ray, with the two pack clear on it, underwater in his chlorinated pool. After two years it looks fine and looks as good as it did when new. I have had this same clear on a marble Giant Hand, a single coat only(normally three coats is the go), and after five years it still looks fine. Gel coats hold up on fiberglass boats, underwater (salt water too); the oldest one I have seen was over 40 years and still going strong.
Considering what is gained (protection of the sculpture and its surface polish), and what is possibly lost (at worst the clear layer may lift on any submerged areas, although I have not yet observed this to happen); even if it does lift on a submerged part, no one will ever know the difference. If this is still a worry, then just keep your work in the air only, give it a coat of wax on occasion, and it will look like the day it was born, forever.
Personally, I prefer a degree of natural weathering on sculpture. To me this seems to properly place them into the timeless dimension where they belong. Provided only that any decay does not affect the structural integrity. Cast marble, I am certain, is impervious, it is also stronger and not prone to shattering as is the natural version. That sort of takes care of flood and earthquake; but fire, well nothing is indestructible.