(March 26, 2019, 8:26 AM EDT) -- PASADENA, Calif. — A man who was injured using a spray-coating gun failed in his attempt to serve as his own expert witness, causing him to lose his product liability case for lack of causation evidence, the Ninth Circuit U.S. Court of Appeals affirmed March 18 (Jason Scott Theis v. Graco, Inc., No. 17-56723, 9th Cir., 2019 U.S. App. LEXIS 7964)....