DEWHEL Thread Aluminum Fitting Silver Review

These connectors appear to be die cast aluminum rather than billet aluminum. I'm trying to weld one to an expansion tank I'm making for my car, I couldn't do it, every time I get a tow light to attach it throws a ton of dirt out of the connector and starts sharpening, never had one Problem with the others, which actually consist of round material (blank). It's absolute rubbish. Sizing and threading are good if anything, but without the option of welding I don't think it matters.