Glasair Pilot reported difficulty maintaining directional control on landing resulted in main landing gear collapse and a runway excursion. Pilot also reported landing gear linkage weld failure.

Narrative

Departed ZZZ1; approximately XA:00 on Day 0 with ATC Tower clearance. No further ATC services. Proceeded northwest; overflying ZZZ2; ZZZ3; ZZZ4; ZZZ5; ZZZ6 at 6;500 msl; and arriving at ZZZ; at approximately XC:00.Made a straight in approach to Runway XX at ZZZ. Gear down with 3 green at approximately 1 mile final. Flaps added gradually to full (40 degrees). Some minor wind gusts on final from approximately 250 degrees. Held aircraft in ground effect to lose airspeed; touched down at approximately 65 kts. around 1000 feet from XX approach end. Gear checked with 3 green while in ground effect.After normal touchdown; airplane drifted slowly right. Corrected with differential braking while also braking to reduce speed. Once tracking slightly left; reduced brakes and airplane again drifted slowly right; Corrected again; on reduction of left brake; left main landing gear collapsed. Left wing tip; aileron and flap contacted runway while aircraft traveled gradually to the right; off of the runway; striking the right main landing gear on a runway edge marking light and collapsing the right main landing gear. Aircraft came to a rest in a nose high attitude with engine at idle in the grass at the edge of the runway.Post incident examination of left main landing gear indicates the side brace stud on the gear leg partially separated from the gear leg at the weld.