Trying to use up some leftover lumber from a deck build. I have a quantity of lightweight 2x10 cedar and also a quantity of 2x12 treated Lifewood available. Planning on building a sofa/hallway table as in the picture. I realize the cedar is not very strong and would probably not last. I'm concerned about the copper added to the treated wood indoors.
Sure and you know the hazards, so just make sure you coat anything and everything with polyurethane. Meaning, dry fit only and then finish everything as individual pieces. So, really no problem, but take your own advice and use both of the softwoods wisely. It's only an Alter Table, but still soft is soft. So, double-up the structure and the fasteners, especially at the leg connections and their shoulder supports. Then, it'll hold up a good long time.