I am also trying to find out more about a William Carder from Ohio. He moved to Missouri as an adult and owned a mill (I don't know what kind). He sufferedand later died from wounds he received during the Civil War. I think his wife's name was Mary Jane Duncan, but I have not found any proof of that. They had 4 children: William, Belle, Columbus, and James (born 5/27/1875, my great grandfather). I don't know the correct order for those children. I have found a William J.L. Carder on the Internet, who was in the Missouri Infantry. I think it might be the right William, because my great grandfather's full name was James Louden Carder (note the J.L.). Louden was a family name, maybe on the mother's side.
Let me know what you think of all this. Thanks, Cindy