Why I skip mold pre-heat on short run casts
I know most people say you must pre-heat molds to prevent cracks. But I think it's not always needed for small jobs. In our foundry, when we do batches of less than a hundred, we pour right into cold molds. For instance, with aluminum sand casts, we've had no issues if the metal is hot enough. This cuts our setup time by half. Some coworkers disagree, saying it risks quality. But in ten years, I've only seen two cracks from doing it this way.