> have fun soldering for few hours per week and let him be with you when you do that.
I just want to follow up and say that as a parent, you should do your best to involve them in whatever it is that you're doing. If you're cooking, have them help you measure things. If you're playing board games, let them move/place the pieces for you. If it's something that they can't safely be involved with, talk to them about what's going on.
Explain what you're doing along the way.
Involve them, and expose them, to a wide range of activities. Children's minds can handle and process a lot more than most people give them credit for.
So don't. If you want him to learn violin you too should learn, show him how fun it is so he can learn with you.
If you want you kid to learn soldering. Then have fun soldering for few hours per week and let him be with you when you do that.
You don't have to (shouldn't?) force anything on your child. Children are starving for fun and are willing to try anything they see you have fun with.