I have a big old hunk of what I think is stainless steel in the form of swimming pool stairs. I thought I would try to apply the grinder spark test to confirm that it is stainless. The problem is that the amount of sparks created is very little and less than I would see with regular steel. I have to look very hard to see them. Is this normal for stainless?

I tested some material I know is aluminum and could see no sparks at all. So I have reached the following preliminary conclusion regarding the grinder test:



Regular steel = lots of sparks
Stainless steel = just a few small sparks
Aluminum = no sparks at all

Is this right?

Thanks!