Using Boily Northstar Colors

It's a fact that some glass coloring chemicals have a lower boiling point than others. This can cause a color
to boil and become bubbly if proper care is not taken to control heating. NS-10 White and NS-40 Sky Blue
are two examples.

Here are some techniques that will help avoid overheating and boiling of the glass.

1. Use a cooler flame, i.e. less oxygen, but note that this is a reducing flame and if your color is sensitive
   to atmosphere it may be affected. NS-10 will develop gray streaks if reduced heavily. Also turning the
   oxygen way up, making a very oxidizing, hissing flame has the effect of making the flame cooler.
2. A flame is usually cooler at the tip and edges of the flame. Work your piece in these areas.
3. Pass the color through the flame, back and forth. This keeps the glass from being overheated by staying
   in a hot part of the flame for too long.
4. When laying down a bead of color, rotate the rod as you lay it down. This presents a cooler side of the
   rod to the flame continually. This prevents one section of the rod from becoming overheated.
5. Clad your color with clear glass, which insulates the color from the flame. You can shrink a tube over
   the color or heat a clear rod and smear an even coat over the color. This can be done on the color rod before
   application or you can clad your artwork with clear after color has been laid down.
6. In general, if you are using a "boily" color, it is best to gradually heat the color up.
   This will minimize boiling.

These notes are intended as a general guide. Individual results will vary depending upon many factors including
type of gas used (i.e. propane or natural gas), type of torch used (surface or internal mix), type of annealing oven
used (gas or electric), and the sequence of heating and cooling. Individual batches of color may vary slightly.
NorthstarŽ BorocolourŽ should come to you pre-labeled for easy identification. Please be sure to store your
glass colors in a manner that allows you to identify which color you are using and which colors to reorder. As
with any glass material, keep them clean and remove any packing tape immediately upon receipt of the glass.
Please observe all normal glass shop health and safety practices.

If you should experience a problem with any of our colors please e-mail or call technical support.
We want to know what your experience is with our colors. Your feedback will help us to continually
improve our products.

Remember: experimentation is the key to diversity as well as the best way to master the use
of NorthstarŽ BorocolourŽ Borosilicate Color Glass.

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