Here's a close-up of the worst damage I could find to the porcelain. This is on the Conoco sign. You can also see from this pic just how thick the porcelin coating is on this. The coating is between a sixteenth and an eighth of an inch thick, on both sides........making the total thickness of the signs really thick. They are very heavy for their size also. I don't know much about porcelain signs if anyone has any info on these please let me know of how old they may be.