Jerry, my experience with POR-15 traditional black has been good. I have mostly used it to stop rust on heavily rusted items. I rebuilt a snow plow and painted it, the cutting edge was pretty rusty and the POR-15 held on well to that surface. On the same project I welded some new steel to the ends of the mold board and hit that with POR-15, it didn't bite into the new steel although I didn't etch the steel. I have used it on other projects and I like it. If you can use the whole container it is advised, not a very good shelf life once the can has been opened.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy