Im using chasers pitch mixed with plaster of paris and linseed oil.
The pitch to soft and now has become brittle after mixing in the
plaster and oil. Any suggestions on what to add to help?
Take a look at the recommendations that Marcia Lewis makes for
pitch. http://www.chasingmetal.com/workshop_info.htm Look for the
section: Chasing & Repousse Workshop - Student Tool & Material Needs
Probably the best thing you can do is to add more pitch to dilute
the effects of what you have already added.
Robin C. McGee