I am disassembling my steel road bike and want to find a long wire brush that I can spin with my electric drill to clean the inside of the seat tube. I saw one used at a bike shop recently, but no one knew where they bought it. Park tool has something similar, but the bristles are too soft. I want something mildly abrasive that will remove surface rust before I spray in the Frame Saver stuff.

Has anyone used one of these and/or know where I can buy one?

Thanks.