The upper horizontal tubing at the back of the cockpit was redone due to mismatch at the joint area. Another tubing was cut and both end was filed for a good fitting. At took quite a while for a fitting. Once completed the horizontal tubing was clamped with a wooden block. The vertical tube at the back of the fuselage (back seat), after proper fitting, was clamped with a wooden block. The diagonal tubing at the aft of the cockpit need further clamping to secure it properly. There is also a need to clamp the horizontal tube at the front of the cockpit supporting the undercarriage for a good fitting. AFTER TODAY, THE TUBE IS READY FOR A TACK WELD.