Each color is designed for a particular application and strike characteristic. NS-013 Amber Purple – the original shade-is best suited for thick blown glass work and sculptural work. This is also the case with the NS-48 Light Blue Amber Purple. The other three shades, (NS-026 Double Amber Purple, NS-049 Dark Blue Amber Purple, and NS-069 Green Amber Purple) are more versatile. The darker shades can be used for sculpture, but they can be stretched much further, making them more suitable for thinner applications. For color tips and suggestions visit our website and call for a complimentary brochure with a step-by-step guide to working the Amber Purples.
The first and most key variable in achieving a purple strike is how the flame is set. Never work the Amber Purples in a reducing flame. Set a sharp oxidizing flame to work these colors. If the flame is not oxidizing enough the color will opacify and turn a milky yellow.
When first heating the color you will notice that there is a metallic haze that precipitates on the surface. This is reduced silver metal that leaches out of the body of the glass and deposits on the surface. If the piece is worked before all the haze is heated off, the layer of metal will thicken and turn a matte gray color, thus masking the true color.
In order to achieve the purple strike once the Amber Purple is applied it must be heated aggressively with a strong sharp flame in order to remove the initial metal deposit. Turn the work slowly in the flame so the heat scrubs the surface of all the haze. The surface must be heated to the point that it almost boils. Even if the flame scars the color it will melt back in and smooth over. This is the crucial step in the whole procedure.
Once the initial layer of haze is removed it will re-develop, but not to the extent of the initial buildup. The redevelopment of the haze can be burned off easily without the extreme heat. With the more intense Amber Purples (NS-026 Double Amber Purple and NS-069 Green Amber Purple) more vigilance must be kept because the haze will redevelop more quickly.
When striking the Amber Purples there are two options, flame or kiln striking.To maximize the strike all the haze must be burned off. To flame strike, allow the piece to cool for twenty seconds so that there is no more heat glow. Then, bathe the piece in a soft neutral flame so that the surface barely glows.
To darken the color, repeat the heating process. By heating for short increments of time, the color can be struck to the desired hue with a greater degree of accuracy. If the color is heated too aggressively, it will over-strike and perhaps the haze will re-deposit.
Flame striking is best suited when a color gradient is desired. To achieve a uniform color all the way through the work, kiln striking is the best option. When kiln striking, place the un-struck (haze free) Amber Purple in the kiln and hold the work at 1125-1150 for approximately sixty minutes or until it reaches the desired level of intensity. Note, some thinner work may slump at these temperatures so be vigilant.
More information on The Amber Purple Family