That depends on how good the welds are. If the welds are very good, the control arm might be stronger than it was when it left the factory (assuming it wasn't heat treated). If the welds are less good, then it won't last as long. I would keep driving on it, but inspect it very regularly.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.