I agree with Al. You probably don't know enough to earn a living on your own.
Let's say that you created business cards, letterheads, sales letters, and all the rest. You sent out five packets a week soliciting new customers and you cold called another five a week during you lunch hour. It's possible that you wouldn't find one customer after three months worth of work.
Let's say that you get a nibble. How much information do you give for free? You might have to prove your worth with information.
Let's say that you get a customer. He needs PQR's, WPS's, and Qualifications for four parts welded by three welders. You need to purchase a Code that you don't have for $200. In it, you discover that you need two other codes that cost $50 each. You might not use the codes ever again.
You build a plunger type bender so that you can bend weld samples. It works pretty well. The tension test is another story. The cheapest place you find to pull the tension strips is $85 each. Each PQR requires two pulls, plus a $100 radiograph!!!
Don't be discouraged, but take it slow. Yes, search for customers. Watch how much info you give for free. Some people will pick your brain for a, "Thank You." Use up-front pricing. Don't be shy. I state my price, plus any code that I don't have, or any test that I can't perform.
You know a lot, but need to know much more.
Keith