It's a full-time job please work full-time hours.Organized labor is why there is an 8 hour work day. Thousands of people went on strike over the years and people were killed to get it finally passed in Congress I think in the late 1930's.
If you are "full-time" and you go to work and do not want/or get paid for at least 8 hours, I see it a violation of both a contract and federal law.
If you want a part-time job then go get a part-time job