jsf252

Hello all, This is my first post but I've been reading as much as possible from this site and other blacksmithing sites. I actually have a 2 part question: #1. I have a large scrap pile of various steels and iron that I want to make use of (which lead me to black/blade smithing). So what is the best way to tell if steel is high or low carbon steel? I have heard that you can file the pieces and feel the difference between high/Low carbon steel. Also I've tried the spark test on a grinding wheel, but I'm not experienced enough to tell the difference between the two. So what do you folks do when you're in the scrap yard looking for high/low carbon steels? #2 I've seen tons of knives with pattern-welded blades, but some of them are far more striking than others. I've seen a few blades that are mostly black with a few veins of silver steel running through them. Other blades have a grey and dark grey pattern that is less pronounced. How do you get that striking black color on the blades where some damascus would have a dark grey? Is it a type of blueing? Any information would be greatly appreciated. -Josh