such as an acrylic binder the use of an acrylic binder in the composition leaves a deposited electrode layer that cannot be rubbed off by hand without the use of this binder the deposited layer can be too soft to withstand processing also fugitive materials may be included in the composition these fugitive materials may be carbon graphite or other types of non dissolved organic materials which will occupy space until the electrode is fired upon firing these materials will leave open porosity in the fully fired electrode the electrodes may be formed from any one of a variety of compositions below are three preferred formulations the first of which has been determined to produce the best results a spark plug fails when the voltage necessary to initiate a spark increases over 25 000 to 30 000 volts the electrical system cannot supply more voltage than approximately 30 000 volts the following table compares the voltage capabilities of spark plugs having different types of electrodes note that some of the plugs produced a spark with 33 000 and 32 000 volts but the spark was irregular so that plugs were considered to have failed the others u201c failed u201d because a spark no longer occurred and thus the demand voltage could not be measured demand voltage new 100 hour 200 hour 300 hour 400 hour standard 16 000 18 000 22 000 22 000 failed platinum tip plug torch.