If you didn't sign a contract at all, then you have this guy by the balls. You could easily go down to the LABOR board and tell them you were an employee with required start times, had to come to their shop, etc. and that they cheated you out of OT, etc. You could also file a form ss-9 with the IRS and have yourself re-classified as an employee. He'll have to pay the employer side taxes that you would normally pay as a self-employed businessman and the IRS will of course be interested to see if this guy has done this to other "employees" and the fines and backtaxes he'll end up owing will probably shut his doors for good.
This is CABL.com posting #199247. Tiny Link: cabl.co/mZZP