I have some pics of my boy (4 y/o) under the car with me changing oil, and wearing a welding helmet while I melted some angle iron.
I have high hopes for him. He didn't last very long on either project, but at least he was out there. I'll let him burn some wire next year if he wants to. He just likes to watch right now.
Good for you! That is where it starts, just letting him be with you whatever you are doing.