[Aim to maim]

I certainly would not suggest that you continue to contribute your time and skill out of the goodness of your heart, but recommend you first give consideration to the ramifications of charging for your services. Once you accept payment, it can be argued that you are in the business of gunsmithing. The first time something you've worked on blows up in the owner's face, his fault, your fault, nobody's fault, you are facing at least the potential of a ruinous lawsuit. It's a shame, but we live in a very litigious society. Whatever else may be said of lawyers, they have to eat, too, and some of them are always hungry.