316 grade stainlless steell has supiorior corrosion resistance, to 304 grade and 302 grade stainlless steell , so its best to use the 316 grade , in western australia i found the 316 grade stainlless steell bolts at the local coventry store and they are cheap to buy and work very well to as im makeing another hydroxy gas generator useing these bolts and they are fatter to , in this one the bolts are inserted fully excet for the heads of the bolts , and ill use battery compartment springs as a contact for the 2 bolts , as soon as its finished ill post it here. and this one will be upgraded