Gazelle

Monday, June 6, 2011

Scott Hansen Briarcliff Manor, New York has a question on burnt umber he’d like some help on

A Summer Project?

I own a homogeneous acid etched Alabaster 6078 vase in the Nautilla pattern. At the time I purchased the vase, the seller described it as “dirty and in need of a good cleaning.” I believe that the piece originally had a burnt umber finish and sometime during its life someone decided to “clean” the vase and removed 90% to 95% of the burnt umber finish. All that remains are hints of the original finish around the noses of the fish and in the crevices of the waves.

Gardner (p. 65) says “These bowls [referring to Calcite lighting domes] were …. often decorated with acid-etched or engraved designs. A brown oxide, such as burnt umber or ocher mixed with linseed oil and turpentine, was frequently rubbed into the etched surfaces to accent the design. This color was not fired on, but was a fairly permanent air-dried pigment.” Gardner again refers to this process on page 113 (when he is discussing etched wares which were advertised as “carved” or “sculptured”) by noting that these terms were usually used “to describe the more expensive designs … , particularly the Calcite and Alabaster pieces that had the raised designs accented with brown air-dried pigment…” A superb example of an original burnt umber finish can be found on the Club’s web site (www.cardersteubenclub.org) in the Colors section.

Burnt umber as a pigment is readily available at art supply stores in either an oil base or acrylic (water) base. It would be a fairly simple process to add turpentine and linseed oil (which I suspect, but don’t know, is used as a drying agent) to burnt umber pigment until something on the order of a brown turpentine “wash” is produced. This “wash” could then be applied with a rag. This application would cause the finish to rub off the high spots and remain in the low, etched portions of an etched piece. Starting with the acrylic (water) base would allow experimentation with different concentrations since presumably colorless turpentine would quickly remove any “undried” pigment. Once the desired finish was obtained, the oil base pigment could be used for a more “permanent” finish (though it would take longer to dry).

My question is this: What should I do with my vase? 1. Leave it “dirty and in need of a good cleaning?” or 2. Finish the cleaning process to remove the remaining 5% to 10% burnt umber finish and end up with just an Alabaster vase? or 3. Try to recreate the original finish?

Does anyone have any experience to help me or any thoughts on how I should proceed?

Thanks. Scott Hansen

www.cardersteubenclub.org

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2011 Carder Steuben Club annual Symposium will be held at The Corning Museum of Glass in Corning, NY from September 15-17, 2011.