On July 03, 2017, about 1630 eastern daylight time, a Waco UPF 7, N134Q, experienced a landing gear collapse while taxing at the McKinnon St Simons Island Airport (SSI), Brunswick, Georgia. The commercial pilot and two passengers were not injured. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local flight.According to the pilot, while taxiing for takeoff the right landing gear strut brace failed at the fuselage attachment point. The right main landing gear collapsed and the airplane came to a complete stop on the taxiway. He inspected the airplane and noted that the right outboard lower wing was buckled. The pilot later received permission from a Federal Aviation Administration (FAA) inspector to remove the airplane from the taxiway. He hoisted the airplane, repaired the strut brace and towed the airplane back to the hangar. Examination the airplane by a Federal Aviation administration (FAA) inspector revealed that the outboard section of the lower right wing was substantially damaged. Examination of the landing gear strut brace revealed that it broke at the fuselage attachment point. Further examination revealed that the pilot had welded the strut back onto the airplane at the point where it had broken, which prevented a more detailed examination of the fracture surface.