What to do when you are only 18 and no credit record, and no co-signer?? for a private bank loan?

The best way to establish credit on your own is to apply for a secured credit card. You will put down a deposit, usually as low as $150.00 and your credit limit will probably be close to the same. There is also an annual fee so check around to find the lowest. Use the card and make 6 months of consistent payments and that will establish a credit history for you. Usually they will refund your deposit if you make consistent payments after six months or a year. Read the details. Good luck.